View source for Project Mercury

{{Short description|Initial American crewed spaceflight program (1958–1963)}}
{{About|the NASA crewed spaceflight program|other uses|Mercury project (disambiguation)}}
{{Use mdy dates|date=August 2015}}
{{Use American English|date=September 2018}}
{{Infobox space program
| name            = Project Mercury
| image           = [[File:Project Mercury logo.svg|frameless|100px|upright]]
| alt             = The astronomical symbol for planet Mercury, with the Arabic numeral 7 overlaid
| caption         = The [[astronomical symbol]] for planet Mercury, with the Arabic numeral 7 overlaid
| country         = [[United States]]
| organization    = [[NASA]]
| purpose         = Crewed orbital flight
| status          = Completed
| cost            = {{Unbulleted list|$277&nbsp;million (1965)<ref name="lafleur20100308" />|${{Format_price|{{Inflation|US|277,000,000|1965|r=2}}}} (adjusted for [[inflation]])}}
| duration        = 1958–1963
| firstflight     = {{Unbulleted list|[[Big Joe 1]]|{{Start date|1959|09|09}}}}
| firstcrewed     = {{Unbulleted list|[[Mercury-Redstone 3]]|{{Start date|1961|05|05}}}}
| lastflight      = {{Unbulleted list|[[Mercury-Atlas 9]]|{{Start date|1963|05|15}}}}
| successes       = 11
| failures        = 3 ([[Mercury-Atlas 1|MA-1]], [[Mercury-Atlas 3|MA-3]], and [[Mercury-Redstone 1|MR-1]])
| partialfailures = 1 (Big Joe 1)
| launchsite      = {{Unbulleted list|[[Cape Canaveral Air Force Station|Cape Canaveral]]|[[Wallops Flight Facility|Wallops]]}}
| crewvehicle     = [[#Spacecraft|Mercury capsule]]
| launcher        = {{Hlist|[[Atlas LV-3B]]|[[Big Joe 1|Big Joe]]|[[RM-90 Blue Scout II|Blue Scout II]]|[[Little Joe (rocket)|Little Joe]]|[[Mercury-Redstone Launch Vehicle|Mercury-Redstone]]}}
}}
{{United States space program sidebar}}

'''Project Mercury''' was the first [[human spaceflight]] program of the United States, running from 1958 through 1963. An early highlight of the [[Space Race]], its goal was to put a man into Earth [[orbital spaceflight|orbit]] and return him safely, ideally before the [[Soviet Union]]. Taken over from the [[US Air Force]] by the newly created civilian space agency [[NASA]], it conducted 20 uncrewed developmental flights (some using animals), and six successful flights by [[astronauts]]. The program, which took its name from [[Mercury (mythology)|Roman mythology]], cost ${{Format_price|{{Inflation|US|277,000,000|1965|r=2}}}} (adjusted for [[inflation]]).<ref name="lafleur20100308"/>{{refn|The project was delayed by 22 months, counting from the beginning until the first orbital mission.{{sfn|Alexander & al.|1966|p=508}} It had a dozen prime contractors, 75 major subcontractors, and about 7200 third-tier subcontractors.{{sfn|Alexander & al.|1966|p=508}} The cost estimate made by NASA in 1969 was $392.6&nbsp;million, broken down as follows: Spacecraft: $135.3 million, launch vehicles: $82.9 million, operations: $49.3 million, tracking operations and equipment: $71.9 million and facilities: $53.2 million.{{sfn|Wilford|1969|p=67}}{{sfn|Alexander & al.|1966|p=643}}|group=n}} The astronauts were collectively known as the "[[Mercury Seven]]", and each spacecraft was given a name ending with a "7" by its pilot.

The Space Race began with the 1957 launch of the Soviet [[satellite]] [[Sputnik 1]]. This came as a shock to the American public, and led to the creation of NASA to expedite existing US space exploration efforts, and place most of them under civilian control. After the successful launch of the [[Explorer 1]] satellite in 1958, crewed spaceflight became the next goal. The Soviet Union put the first human, [[cosmonaut]] [[Yuri Gagarin]], into a single orbit aboard [[Vostok 1]] on April 12, 1961. Shortly after this, on May 5, the US launched its first astronaut, [[Alan Shepard]], on a [[suborbital]] flight. Soviet [[Gherman Titov]] followed with a day-long orbital flight in August 1961. The US reached its orbital goal on February 20, 1962, when [[John Glenn]] made three orbits around the Earth. When Mercury ended in May 1963, both nations had sent six people into space, but the Soviets led the US in total time spent in space.

The Mercury [[space capsule]] was produced by [[McDonnell Aircraft]], and carried supplies of water, food and oxygen for about one day in a [[Cabin pressurization|pressurized cabin]]. Mercury flights were launched from [[Cape Canaveral Air Force Station]] in Florida, on [[launch vehicle]]s modified from the [[Redstone MRLV|Redstone]] and [[Atlas LV-3B|Atlas D]] missiles. The capsule was fitted with a [[launch escape system|launch escape rocket]] to carry it safely away from the launch vehicle in case of a failure. The flight was designed to be controlled from the ground via the [[Manned Space Flight Network]], a system of tracking and communications stations; back-up controls were outfitted on board. Small [[retrorocket]]s were used to bring the spacecraft out of its orbit, after which an [[ablative heat shield]] protected it from the heat of [[atmospheric entry|atmospheric reentry]]. Finally, a [[parachute]] slowed the craft for a [[Splashdown|water landing]]. Both astronaut and capsule were recovered by helicopters deployed from a US Navy ship.

The Mercury project gained popularity, and its missions were followed by millions on radio and TV around the world. Its success laid the groundwork for [[Project Gemini]], which carried two astronauts in each capsule and perfected space docking maneuvers essential for crewed [[Moon landing|lunar landings]] in the subsequent [[Apollo program]] announced a few weeks after the first crewed Mercury flight.

==Creation==
Project Mercury was officially approved on October 7, 1958, and publicly announced on December 17.{{sfn|Grimwood|1963|p=12}}{{sfn|Alexander & al.|1966|p=132}} Originally called Project Astronaut, President [[Dwight Eisenhower]] felt that gave too much attention to the pilot.{{sfn|Catchpole|2001|p=92}} Instead, the name ''[[Mercury (mythology)|Mercury]]'' was chosen from [[classical mythology]], which had already lent names to rockets like the Greek ''[[Atlas (mythology)|Atlas]]'' and Roman ''[[Jupiter (mythology)|Jupiter]]'' for the [[SM-65 Atlas|SM-65]] and [[PGM-19 Jupiter|PGM-19]] [[missiles]].{{sfn|Alexander & al.|1966|p=132}} It absorbed military projects with the same aim, such as the Air Force [[Man in Space Soonest]].{{sfn|Alexander & al.|1966|p=102}}{{refn|Man in Space Soonest was the first part of a four-phase Moon landing program estimated to finish in 1965, cost a total of $1.5&nbsp;billion (${{Formatprice|{{Inflation|US|1500000000|1959|r=1}}}} adjusted for inflation), and be launched by a "Super Titan" rocket.{{sfn|Alexander & al.|1966|p=91}}|group=n}}

=== Background ===
Following the end of [[World War II]], a [[nuclear arms race]] evolved between the US and the [[Soviet Union]] (USSR). Since the USSR did not have bases in the western hemisphere from which to deploy [[bomber|bomber planes]], [[Joseph Stalin]] decided to develop [[intercontinental ballistic missile]]s, which drove a missile race.{{sfn|Catchpole|2001|pp=12–14}} The rocket technology in turn enabled both sides to develop Earth-orbiting satellites for communications, and gathering weather data and [[geospatial intelligence|intelligence]].{{sfn|Catchpole|2001|p=81}} Americans were shocked when the Soviet Union placed the first satellite into orbit in October 1957, leading to a growing fear that the US was falling into a "[[missile gap]]".{{sfn|Alexander & al.|1966|pp=28, 52}}{{sfn|Catchpole|2001|p=81}} A month later, the Soviets launched [[Sputnik 2]], carrying [[Laika|a dog]] into orbit. Though the animal was not recovered alive, it was obvious their goal was human spaceflight.{{sfn|Catchpole|2001|p=55}} Unable to disclose details of military space projects, President Eisenhower ordered the creation of a civilian space agency in charge of civilian and scientific space exploration. Based on the federal research agency [[National Advisory Committee for Aeronautics]] (NACA), it was named the National Aeronautics and Space Administration (NASA).{{sfn|Alexander & al.|1966|p=113}} The agency achieved its first goal of launching a satellite into space, the [[Pioneer 1]], in 1958. The next goal was to put a man there.{{sfn|Catchpole|2001|pp=57, 82}}

The limit of space (also known as the [[Kármán line]]) was defined at the time as a minimum altitude of {{convert|62|mi|abbr=on}}, and the only way to reach it was by using rocket-powered boosters.{{sfn|Catchpole|2001|p=70}}{{sfn|Alexander & al.|1966|p=13}} This created risks for the pilot, including explosion, high [[g-force]]s and vibrations during lift off through a dense atmosphere,{{sfn|Alexander & al.|1966|p=44}} and temperatures of more than {{convert|10000|°F|abbr=on|sigfig=2}} from air compression during reentry.{{sfn|Alexander & al.|1966|p=59}}

In space, pilots would require pressurized chambers or [[space suit]]s to supply fresh air.{{sfn|Catchpole|2001|p=466}} While there, they would experience [[weightlessness]], which could potentially cause disorientation.{{sfn|Alexander & al.|1966|p=357}} Further potential risks included [[space radiation|radiation]] and [[micrometeoroid]] strikes, both of which would normally be absorbed in the atmosphere.{{sfn|Alexander & al.|1966|pp=35, 39–40}} All seemed possible to overcome: experience from satellites suggested micrometeoroid risk was negligible,{{sfn|Alexander & al.|1966|p=49}} and experiments in the early 1950s with simulated weightlessness, high g-forces on humans, and sending animals to the limit of space, all suggested potential problems could be overcome by known technologies.{{sfn|Alexander & al.|1966|pp=37–38}} Finally, reentry was studied using the nuclear warheads of ballistic missiles,{{sfn|Alexander & al.|1966|p=61}} which demonstrated a blunt, forward-facing heat shield could solve the problem of heating.{{sfn|Alexander & al.|1966|p=61}}

===Organization===
[[T. Keith Glennan]] had been appointed the first Administrator of NASA, with [[Hugh L. Dryden]] (last Director of NACA) as his Deputy, at the creation of the agency on October 1, 1958.{{sfn|Alexander & al.|1966|pp=98–99}} Glennan would report to the president through the [[National Space Council|National Aeronautics and Space Council]].{{sfn|Catchpole|2001|p=82}} The group responsible for Project Mercury was NASA's [[Space Task Group]], and the goals of the program were to orbit a crewed spacecraft around Earth, investigate the pilot's ability to function in space, and to recover both pilot and spacecraft safely.{{sfn|Alexander & al.|1966|pp=xiii, 134}} Existing technology and off-the-shelf equipment would be used wherever practical, the simplest and most reliable approach to system design would be followed, and an existing launch vehicle would be employed, together with a progressive test program.{{sfn|Alexander & al.|1966|p=134}} Spacecraft requirements included: a [[launch escape system]] to separate the spacecraft and its occupant from the [[launch vehicle]] in case of impending failure; [[Spacecraft attitude control|attitude control]] for orientation of the spacecraft in orbit; a [[retrorocket]] system to bring the spacecraft out of orbit; drag braking [[Blunt Body theory|blunt body]] for [[atmospheric entry|atmospheric reentry]]; and landing on water.{{sfn|Alexander & al.|1966|p=134}} To communicate with the spacecraft during an orbital mission, an extensive communications network had to be built.{{sfn|Alexander & al.|1966|p=143}} In keeping with his desire to keep from giving the US space program an overtly military flavor, President Eisenhower at first hesitated to give the project top national priority (DX rating under the [[Defense Production Act]]), which meant that Mercury had to wait in line behind military projects for materials; however, this rating was granted in May 1959, a little more than a year and a half after Sputnik was launched.{{sfn|Catchpole|2001|p=157}}

===Contractors and facilities===

Twelve companies bid to build the Mercury spacecraft on a $20&nbsp;million (${{Formatprice|{{Inflation|US|20000000|1959|r=-2}}}} adjusted for inflation) contract.{{sfn|Alexander & al.|1966|pp=121, 191}} In January 1959, [[McDonnell Aircraft|McDonnell Aircraft Corporation]] was chosen to be prime contractor for the spacecraft.{{sfn|Alexander & al.|1966|p=137}} Two weeks earlier, [[North American Aviation]], based in Los Angeles, was awarded a contract for [[Little Joe (rocket)|Little Joe]], a small rocket to be used for development of the launch escape system.{{sfn|Alexander & al.|1966|p=124}}{{refn|group=n|The name ''Little Joe'' was adopted by its designers from the throw of a double deuce in a [[craps]] game since this resembled the four-rocket arrangement in the blueprints for the vehicle.{{sfn|Alexander & al.|1966|p=124}}}} The World Wide Tracking Network for communication between the ground and spacecraft during a flight was awarded to the [[Western Electric|Western Electric Company]].{{sfn|Alexander & al.|1966|p=216}} Redstone rockets for suborbital launches were manufactured in [[Huntsville, Alabama|Huntsville]], Alabama, by the [[Chrysler Corporation]]{{sfn|Alexander & al.|1966|p=21}} and Atlas rockets by [[Convair]] in San Diego, California.{{sfn|Catchpole|2001|p=158}} For crewed launches, the [[Atlantic Missile Range]] at [[Cape Canaveral Air Force Station]] in Florida was made available by the USAF.{{sfn|Catchpole|2001|p=89–90}} This was also the site of the Mercury Control Center while the computing center of the communication network was in [[Goddard Space Center]], Maryland.{{sfn|Catchpole|2001|p=86}} Little Joe rockets were launched from [[Wallops Island]], Virginia.{{sfn|Alexander & al.|1966|p=141}} Astronaut training took place at [[Langley Research Center]] in Virginia, [[Lewis Flight Propulsion Laboratory]] in Cleveland, Ohio, and [[Naval Air Development Center|Naval Air Development Center Johnsville]] in Warminster, PA.{{sfn|Catchpole|2001|pp=103–110}} Langley wind tunnels{{sfn|Alexander & al.|1966|p=88}} together with a rocket sled track at [[Holloman Air Force Base]] at Alamogordo, New Mexico were used for aerodynamic studies.{{sfn|Catchpole|2001|p=248}} Both Navy and Air Force aircraft were made available for the development of the spacecraft's landing system,{{sfn|Catchpole|2001|pp=172–173}} and Navy ships and Navy and Marine Corps helicopters were made available for recovery.{{refn|NASA's planning for recovery operations in the summer of 1960 was, according to the Navy, asking for the deployment of the whole Atlantic Fleet and might have cost more than the entire Mercury program.{{sfn|Alexander & al.|1966|p=265}}|group=n}} South of Cape Canaveral the town of [[Cocoa Beach]] boomed.<ref name="CocoaBeach" /> From here, 75,000 people watched the first American orbital flight being launched in 1962.<ref name="CocoaBeach" />

<gallery mode="packed">
File:Wallops Island - GPN-2000-001888.jpg|[[Wallops Island]] test facility, 1961
File:Mercury control center 4june1963.jpg|[[Mercury Control Center]], Cape Canaveral, 1963
File:Project-Mercury-facility-map.png|Location of production and operational facilities of Project Mercury
</gallery>

== Spacecraft ==
The Mercury spacecraft's principal designer was [[Maxime Faget]], who started research for human spaceflight during the time of the NACA.{{sfn|Catchpole|2001|p=150}} It was {{convert|10.8|ft}} long and {{convert|6.0|ft}} wide; with the launch escape system added, the overall length was {{convert|25.9|ft}}.{{sfn|Catchpole|2001|p=131}} With {{convert|100|ft3|m3}} of habitable volume, the capsule was just large enough for a single crew member.{{sfn|Alexander & al.|1966|p=47}} Inside were 120 controls: 55 electrical switches, 30 [[Fuse (electrical)|fuses]] and 35 mechanical levers.{{sfn|Alexander & al.|1966|p=245}} The heaviest spacecraft, Mercury-Atlas 9, weighed {{convert|3000|lb}} fully loaded.{{sfn|Alexander & al.|1966|p=490}} Its outer skin was made of [[René 41]], a nickel alloy able to withstand high temperatures.{{sfn|Catchpole|2001|p=136}}

The spacecraft was cone shaped, with a neck at the narrow end.{{sfn|Catchpole|2001|p=131}} It had a convex base, which carried a heat shield (Item '''2''' in the diagram below){{sfn|Catchpole|2001|pp=134–136}} consisting of an aluminum [[honeycomb structure|honeycomb]] covered with multiple layers of [[fiberglass]].{{sfn|Alexander & al.|1966|pp=140, 143}} Strapped to it was a retropack ('''1'''){{sfn|Catchpole|2001|pp=132–134}} consisting of three rockets deployed to brake the spacecraft during reentry.{{sfn|Catchpole|2001|p=132}} Between these were three posigrade rockets: minor rockets for separating the spacecraft from the launch vehicle at orbital insertion.{{sfn|Alexander & al.|1966|p=188}} The straps that held the package could be severed when it was no longer needed.{{sfn|Catchpole|2001|p=134}} Next to the heat shield was the pressurized crew compartment ('''3''').{{sfn|Catchpole|2001|pp=136–144}} Inside, an astronaut would be strapped to a form-fitting seat with instruments in front of him and with his back to the heat shield.{{sfn|Catchpole|2001|pp=136–137}} Underneath the seat was the environmental control system supplying oxygen and heat,{{sfn|Catchpole|2001|p=138}} scrubbing the air of CO<sub>2</sub>, vapor and odors, and (on orbital flights) collecting urine.{{sfn|Catchpole|2001|p=139}} The recovery compartment ('''4'''){{sfn|Catchpole|2001|pp=144–145}} at the narrow end of the spacecraft contained three parachutes: a drogue to stabilize free fall and two main chutes, a primary and reserve.{{sfn|Catchpole|2001|p=144}} Between the heat shield and inner wall of the crew compartment was a landing skirt, deployed by letting down the heat shield before landing.{{sfn|Catchpole|2001|p=135}} On top of the recovery compartment was the [[Antenna (radio)|antenna]] section ('''5'''){{sfn|Catchpole|2001|pp=145–148}} containing both antennas for communication and scanners for guiding spacecraft orientation.{{sfn|Catchpole|2001|p=147}} Attached was a flap used to ensure the spacecraft was faced heat shield first during reentry.{{sfn|Alexander & al.|1966|p=199}} A launch escape system ('''6''') was mounted to the narrow end of the spacecraft{{sfn|Catchpole|2001|pp=179–181}} containing three small solid-fueled rockets which could be fired briefly in a launch failure to separate the capsule safely from its booster. It would deploy the capsule's parachute for a landing nearby at sea.{{sfn|Catchpole|2001|p=179}} (See also [[#Mission profile|Mission profile]] for details.)

The Mercury spacecraft did not have an on-board computer, instead relying on all computation for reentry to be calculated by computers on the ground, with their results (retrofire times and firing attitude) then transmitted to the spacecraft by radio while in flight.<ref name="NASAComp1" /><ref name="DanCompSpace" /> All computer systems used in the Mercury space program were housed in [[NASA]] facilities on [[Earth]].<ref name="NASAComp1" /> (See [[#Ground control|ground control]] for details.)

<gallery mode="packed">
Mercury-spacecraft-color.png|1. Retropack. 2. Heatshield. 3. Crew compartment. 4. Recovery compartment. 5. Antenna section. 6. Launch escape system.
McDonnellMercuryCapsule1.jpg|Retropack: Retrorockets with red posigrade rockets
Landing-skirt.jpg|Landing skirt (or bag) deployment: skirt is inflated; on impact the air is pressed out (like an [[airbag]])
</gallery>

===Pilot accommodations===
[[File:GPN-2000-001027.jpg|thumb|upright|[[John Glenn]] wearing his [[Mercury space suit]]]]

The astronaut lay in a sitting position with his back to the heat shield, which was found to be the position that best enabled a human to withstand the high [[g-force]]s of launch and reentry. A fiberglass seat was custom-molded from each astronaut's space-suited body for maximum support. Near his left hand was a manual abort handle to activate the launch escape system if necessary prior to or during liftoff, in case the automatic trigger failed.{{sfn|Catchpole|2001|p=142}}

To supplement the onboard environmental control system, he wore a [[pressure suit]] with its own [[oxygen]] supply, which would also cool him.{{sfn|Catchpole|2001|p=191}} A cabin atmosphere of pure oxygen at a low pressure of {{cvt|5.5|psi|disp=or}} (equivalent to the [[partial pressure]] of oxygen at sea level or the pressure of atmospheric air at an altitude of {{convert|24800|ft|disp=or}}) was chosen, rather than the atmosphere at sea level.{{sfn|Gatland|1976|p=264}} This was easier to control,{{sfn|Catchpole|2001|p=410}} avoided the risk of [[decompression sickness]] ("the bends"),{{sfn|Giblin|1998|p=}}{{refn|group=n|The decision to eliminate the use of any gas but oxygen was crystalized when a serious accident occurred on April 21, 1960, in which McDonnell Aircraft test pilot G.B. North passed out and was seriously injured when testing a Mercury cabin/spacesuit atmosphere system in a vacuum chamber. The problem was found to be nitrogen-rich (oxygen-poor) air leaking from the cabin into his spacesuit feed.{{sfn|Giblin|1998|p=}}}} and also saved on spacecraft weight. Fires (which never occurred during the course of Project Mercury) would have to be extinguished by emptying the cabin of oxygen.{{sfn|Catchpole|2001|p=139}} In such case, or failure of the cabin pressure for any reason, the astronaut could make an emergency return to Earth, relying on his suit for survival.{{sfn|Alexander & al.|1966|pp=48–49}}{{sfn|Catchpole|2001|p=139}} The astronauts normally flew with their [[visor]] up, which meant that the suit was not inflated.{{sfn|Catchpole|2001|p=139}} With the visor down and the suit inflated, the astronaut could only reach the side and bottom panels, where vital buttons and handles were placed.{{sfn|Alexander & al.|1966|p=246}}

The astronaut also wore [[electrode]]s on his chest to record his [[heart rhythm]], a cuff that could take his blood pressure, and a [[Medical thermometer|rectal thermometer]] to record his temperature (this was replaced by an oral thermometer on the last flight).{{sfn|Catchpole|2001|pp=191, 194}} Data from these was sent to the ground during the flight.{{sfn|Catchpole|2001|p=191}}{{refn|group=n|Pilot and spacecraft data sent automatically to the ground is called [[telemetry]].{{sfn|Alexander & al.|1966|p=313}}}} The astronaut normally drank water and ate food pellets.{{sfn|Catchpole|2001|pp=343–344}}{{refn|group=n|Moisture and urine was recycled into drinking water.{{sfn|Alexander & al.|1966|p=47}}}}

Despite the lessons learnt from the [[Lockheed U-2|U2]] program, which also utilized a pressure suit, initially no urine collection device was included for the Mercury astronauts. An inquiry on the subject was made in February 1961 by a student, but NASA responded by stating that "the first space man is not expected to have 'to go".{{sfn|Hollins|2013|p=}} The expected short flight times meant that this was overlooked, although after Alan Shepard had a launch delay of four hours, he was forced to urinate in his suit, short-circuiting some of the electrodes monitoring his vital signs. Gus Grissom wore two rubber pants on the second Mercury flight as a crude workaround. It would take until the third flight in February 1962 before a dedicated urine collection device was installed.<ref>{{cite web |url=https://abcnews.go.com/Technology/history-urinating-space/story?id=19641585 |title=The History of Urinating in Space |publisher=ABC |access-date=27 Dec 2023}}</ref>

Once in orbit, the spacecraft could be rotated in [[yaw, pitch, and roll]]: along its longitudinal axis (roll), left to right from the astronaut's point of view (yaw), and up or down (pitch).{{sfn|Alexander & al.|1966|p=98}} Movement was created by [[Rocket engine|rocket-propelled]] thrusters which used [[hydrogen peroxide]] as a fuel.{{sfn|Alexander & al.|1966|p=499}}{{sfn|Catchpole|2001|p=143}} For orientation, the pilot could look through the window in front of him or he could look at a screen connected to a [[periscope]] with a camera which could be turned 360°.{{sfn|Catchpole|2001|p=141}}

The Mercury astronauts had taken part in the development of their spacecraft, and insisted that manual control, and a window, be elements of its design.{{sfn|Catchpole|2001|pp=98–99}} As a result, spacecraft movement and other functions could be controlled three ways: remotely from the ground when passing over a ground station, automatically guided by onboard instruments, or manually by the astronaut, who could replace or override the two other methods. Experience validated the astronauts' insistence on manual controls. Without them, [[Gordon Cooper]]'s manual reentry during the last flight would not have been possible.{{sfn|Alexander & al.|1966|p=501}}

{{hidden begin|title={{center|Cutaways and interior of spacecraft}}|style=border:solid 1px #aaa;background:#F9F9F9;padding-left:10px;}}
;Spacecraft cutaway
<gallery mode="packed">
Mercury Spacecraft.png|Interior of spacecraft
Mercury-spacecraft-control.png|The three axes of rotation for the spacecraft: yaw, pitch and roll
Mercury-spacecraft-temperature-profile.png|Temperature profile for spacecraft in [[Fahrenheit]]
</gallery>

;Control panels and handle
<gallery mode="packed">
Control panels mercury atlas 6.png|The control panels of ''Friendship 7''.{{sfn|Unknown|1962|p=8}} The panels changed between flights, among others the periscope screen that dominates the center of these panels was dropped for the final flight together with the periscope itself.
Three-axis hand controller mercury project.jpg|3-axis handle for attitude control
</gallery>
{{clear}}
{{hidden end}}

===Development and production===
[[File:Technicians working in the McDonnell White Room on the Mercury-crop.jpg|thumb|upright|Spacecraft production in clean room at [[McDonnell Aircraft]], St. Louis, 1960]]
The Mercury spacecraft design was modified three times by NASA between 1958 and 1959.{{sfn|Catchpole|2001|p=152}} After bidding by potential contractors had been completed, NASA selected the design submitted as "C" in November 1958.{{sfn|Catchpole|2001|p=153}} After it failed a test flight in July 1959, a final configuration, "D", emerged.{{sfn|Catchpole|2001|p=159}} The heat shield shape had been developed earlier in the 1950s through experiments with ballistic missiles, which had shown a blunt profile would create a shock wave that would lead most of the heat around the spacecraft.{{sfn|Catchpole|2001|p=149}} To further protect against heat, either a [[heat sink]], or an ablative material, could be added to the shield.{{sfn| Alexander & al.|1966|p=63}} The heat sink would remove heat by the flow of the air inside the shock wave, whereas the ablative heat shield would remove heat by a controlled evaporation of the ablative material.{{sfn| Alexander & al.|1966|p=64}} After uncrewed tests, the latter was chosen for crewed flights.{{sfn| Alexander & al.|1966|p=206}} Apart from the capsule design, a [[rocket plane]] similar to the existing [[X-15]] was considered.{{sfn| Alexander & al.|1966|pp=78–80}} This approach was still too far from being able to make a spaceflight, and was consequently dropped.{{sfn| Alexander & al.|1966|p=72}}{{refn|group=n|The rocket plane approach to human space flight was pursued by the Air Force with their [[Boeing X-20 Dyna-Soar|Dyna-Soar]] project, which was canceled in 1963.{{sfn|Catchpole|2001|pp=425, 428}} Toward the end of the 1960s, NASA began the development of a reusable space plane, which was ultimately developed into the [[Space Shuttle]] program.<ref>{{cite web|title=Introduction to future launch vehicle plans [1963–2001]. 3.The Space Shuttle (1968–72)|url=http://www.pmview.com/spaceodysseytwo/spacelvs/sld001.htm|access-date=3 February 2014}}</ref> The first rocket plane to enter space was an X-15 in 1963.<ref>{{cite web|last1=Garber|first1=Steve|title=X – 15 Hypersonic Research at the Edge of Space|url=https://history.nasa.gov/x15/cover.html|website=NASA History Homepage|publisher=NASA|access-date=18 July 2015}}</ref>}} The heat shield and the stability of the spacecraft were tested in [[supersonic wind tunnel|wind tunnels]],{{sfn|Alexander & al.|1966|p=88}} and later in flight.{{sfn|Catchpole|2001|p=229}} The launch escape system was developed through uncrewed flights.{{sfn|Catchpole|2001|p=196}} During a period of problems with development of the landing parachutes, alternative landing systems such as the [[Rogallo wing|Rogallo glider wing]] were considered, but ultimately scrapped.{{sfn| Alexander & al.|1966|p=198}}

The spacecraft were produced at [[McDonnell Aircraft]], [[St. Louis, Missouri|St. Louis]], Missouri, in clean rooms and tested in vacuum chambers at the McDonnell plant.{{sfn|Catchpole|2001|pp=132, 159}} The spacecraft had close to 600 subcontractors, such as [[Garrett AiResearch]] which built the spacecraft's environmental control system.{{sfn| Alexander & al.|1966|p=137}}{{sfn|Catchpole|2001|p=138}} Final quality control and preparations of the spacecraft were made at Hangar S at Cape Canaveral.{{sfn|Catchpole|2001|pp=184–188}}{{refn|Test and rework of Mercury-Redstone 2 at the Hangar required 110 days.{{sfn|Alexander & al.|1966|p=310}} Hangar S was also the place where the chimpanzees were trained.{{sfn|Alexander & al.|1966|p=312}}|group=n}} NASA ordered 20 production spacecraft, numbered 1 through 20.{{sfn|Alexander & al.|1966|p=137}} Five of the 20, Nos. 10, 12, 15, 17, and 19, were not flown.{{sfn|Grimwood|1963|pp=235–238}} Spacecraft No. 3 and No. 4 were destroyed during uncrewed test flights.{{sfn|Grimwood|1963|pp=235–238}} Spacecraft No. 11 sank and was recovered from the bottom of the Atlantic Ocean after 38 years.{{sfn|Grimwood|1963|pp=235–238}}{{sfn|Catchpole|2001|pp=402–405}} Some spacecraft were modified after initial production (refurbished after launch abort, modified for longer missions, etc.).{{refn|They received a letter designation after their number, ''e.g.'', 2B, 15B.{{sfn|Grimwood|1963|pp=216–218}} Some were modified twice: for example, spacecraft 15 became 15A and then 15B.{{sfn|Grimwood|1963|p=149}}|group=n}} A number of Mercury [[Boilerplate (spaceflight)|boilerplate spacecraft]] (made from non-flight materials or lacking production spacecraft systems) were also made by NASA and McDonnell.{{sfn|Alexander & al.|1966|pp=126 & 138}} They were designed and used to test spacecraft recovery systems and the escape tower.{{sfn|Alexander & al.|1966|pp=96, 105}} McDonnell also built the spacecraft simulators used by the astronauts during training,{{sfn|Catchpole|2001|p=107}} and adopted the motto "First Free Man in Space".<ref name="logo_history">{{citation |url= http://www.mdc.com/version2/history/logo.htm |publisher= McDonnell Douglas |title= McDonnell Douglas Logo History |access-date= 29 November 2020 |archive-url= https://web.archive.org/web/19970605044807/http://www.mdc.com/version2/history/logo.htm |archive-date= 5 June 1997 |url-status= dead }}</ref>

<gallery mode="packed">
Heatshield-test3.jpg|[[Shadowgraph]] of the reentry [[shock wave]] simulated in a [[supersonic wind tunnel|wind tunnel]], 1957
Mercury-design.png|Evolution of capsule design, 1958–59
Mercury Space Capsule-wind-tunnel.jpg|Experiment with boilerplate spacecraft, 1959
</gallery>
{{clear}}

{{hidden begin|title={{center|Development of Earth landing system}}|style=border:solid 1px #aaa;background:#F9F9F9;padding-left:10px;}}
<gallery mode="packed">
Mercury-project-earth-landing-system-test.png|Drop of boilerplate spacecraft in training of landing and recovery. 56 such qualification tests were made together with tests of individual steps of the system.{{sfn|Catchpole|2001|pp=172-173}}
</gallery>
{{clear}}
{{hidden end}}

==Launch vehicles==
[[File:Mercury-launch-vehicles.png|thumb|upright=1.4|Launch vehicles: 1. Mercury-Atlas (orbital flights). 2. Mercury-Redstone (suborbital flights). 3. Little Joe (uncrewed tests)]]

===Launch escape system testing===
A {{convert|55|ft|m|adj=mid|-long}} launch vehicle called [[Little Joe (rocket)|Little Joe]] was used for uncrewed tests of the launch escape system, using a Mercury capsule with an escape tower mounted on it.{{sfn|Catchpole|2001|p=197}}{{sfn|Alexander & al.|1966|p=638}} Its main purpose was to test the system at [[max q]], when aerodynamic forces against the spacecraft peaked, making separation of the launch vehicle and spacecraft most difficult.{{sfn|Catchpole|2001|p=223}} It was also the point at which the astronaut was subjected to the heaviest vibrations.{{sfn|Catchpole|2001|p=284}} The Little Joe rocket used [[solid-fuel rocket|solid-fuel]] propellant and was originally designed in 1958 by NACA for suborbital crewed flights, but was redesigned for Project Mercury to simulate an Atlas-D launch.{{sfn|Catchpole|2001|p=196}} It was produced by [[North American Aviation]].{{sfn|Catchpole|2001|p=197}} It was not able to change direction; instead its flight depended on the angle from which it was launched.{{sfn|Catchpole|2001|p=198}} Its maximum altitude was {{convert|100|mi|abbr=on}} fully loaded.{{sfn|Alexander & al.|1966|p=125}} A [[Mercury-Scout 1|Scout launch vehicle]] was used for a single flight intended to evaluate the tracking network; however, it failed and was [[Range safety|destroyed from the ground]] shortly after launch.{{sfn|Alexander & al.|1966|pp=392–397}}

===Suborbital flight===
{{Multiple image |total_width=365px
|image1=Chimpanzee Ham in Biopack Couch - cropped.jpg|caption=
|image2=Mercury-Atlas 5 Enos with handler (cropped).jpg |caption2=
|footer=Space pioneers [[Ham (chimpanzee)|Ham]] (left), who became the first [[great ape]] in space during his [[Mercury-Redstone 2|January 31, 1961, mission]], and [[Enos (chimpanzee)|Enos]], The only chimpanzee and the third primate to orbit the Earth ([[Mercury-Atlas 5|November 29, 1961]]), were research subjects in the Project Mercury program.}}
The [[Mercury-Redstone Launch Vehicle]] was an {{convert|83|ft|m|adj=mid|-tall}} (with capsule and escape system) single-stage launch vehicle used for suborbital ([[ballistic missile|ballistic]]) flights.{{sfn|Catchpole|2001|p=206}} It had a liquid-fueled engine that burned alcohol and liquid oxygen producing about {{convert|75,000|lbf|kN}} of thrust, which was not enough for orbital missions.{{sfn|Catchpole|2001|p=206}} It was a descendant of the German [[V-2 (rocket)|V-2]],{{sfn|Alexander & al.|1966|p=21}} and developed for the [[US Army]] during the early 1950s. It was modified for Project Mercury by removing the warhead and adding a collar for supporting the spacecraft together with material for damping vibrations during launch.{{sfn|Catchpole|2001|p=207}} Its rocket motor was produced by [[North American Aviation]] and its direction could be altered during flight by its fins. They worked in two ways: by directing the air around them, or by directing the thrust by their inner parts (or both at the same time).{{sfn|Alexander & al.|1966|p=21}} Both the Atlas-D and Redstone launch vehicles contained an automatic abort sensing system which allowed them to abort a launch by firing the launch escape system if something went wrong.{{sfn|Catchpole|2001|pp=209, 214}} The [[Mercury-Jupiter|Jupiter]] rocket, also developed by [[Wernher von Braun]]'s team at the Redstone Arsenal in Huntsville, was considered as well for intermediate Mercury suborbital flights at a higher speed and altitude than Redstone, but this plan was dropped when it turned out that man-rating Jupiter for the Mercury program would actually cost more than flying an Atlas due to economics of scale.{{sfn|Alexander & al.|1966|p=151}}{{sfn|Grimwood|1963|p=69}} Beyond its IRBM function, the Jupiter missile was repurposed only for the short-lived Juno II launch vehicle, and sustaining a dedicated technical staff solely for a handful of Mercury capsule launches would have been cost-prohibitive.<ref>{{cite web |title=Project Mercury – A Chronology (NASA SP-4001)|author=Loyd S. Swenson Jr.; James M. Grimwood; Charles C. Alexander|year=1963|publisher=NASA History Office|url=https://ntrs.nasa.gov/api/citations/19630011968/downloads/19630011968.pdf|accessdate=August 8, 2025}}</ref>

===Orbital flight===
Orbital missions required use of the [[Atlas LV-3B]], a man-rated version of the [[SM-65D Atlas|Atlas D]] which was originally developed as the [[United States]]' first operational [[intercontinental ballistic missile|intercontinental ballistic missile (ICBM)]]{{sfn|Catchpole|2001|p=211}} by [[Convair]] for the Air Force during the mid-1950s.{{sfn|Alexander & al.|1966|p=22}} The Atlas was a "one-and-one-half-stage" rocket fueled by [[kerosene]] and liquid [[oxygen]] (LOX).{{sfn|Catchpole|2001|p=211}} The rocket by itself stood {{convert|67|ft}} high; total height of the Atlas-Mercury space vehicle at launch was {{convert|95|ft}}.{{sfn|Catchpole|2001|p=212}}

The Atlas first stage was a booster skirt with two engines burning liquid fuel.{{sfn|Catchpole|2001|pp=225, 250}}{{refn|group=n|At the time, the word "booster" was sometimes used for the first stage of the launch stack. Later, "booster" came to refer to additional single-stage rockets attached to the sides of the main launch vehicle, as on the Space Shuttle.}} This, together with the larger sustainer second stage, gave it sufficient power to launch a Mercury spacecraft into orbit.{{sfn|Catchpole|2001|p=211}} Both stages fired from lift-off with the thrust from the second stage sustainer engine passing through an opening in the first stage. After separation from the first stage, the sustainer stage continued alone. The sustainer also steered the rocket by thrusters guided by gyroscopes.{{sfn|Catchpole|2001|pp=458–459}} Smaller vernier rockets were added on its sides for precise control of maneuvers.{{sfn|Catchpole|2001|p=211}}

===Gallery===
<gallery mode="packed">
Little Joe 5B capsule mating.jpg|Little Joe assembling at Wallops Island
Mercury-Redstone 4 booster erectionWB.jpg|Erection of Redstone at [[Cape Canaveral Air Force Station Launch Complex 5|Launch Complex 5]]
Unloading Atlas Launch Vehicle - GPN-2003-00041.jpg|Unloading Atlas at Cape Canaveral
Launch Complex 14-MA-9.jpg|Atlas - with spacecraft mounted - on launch pad at Launch Complex 14
</gallery>
{{clear}}

== Astronauts ==
[[File:Project Mercury-Mercury Seven-Astronauts.jpg|thumb|upright=1.35|Left to right: [[Gus Grissom|Grissom]], [[Alan Shepard|Shepard]], [[Scott Carpenter|Carpenter]], [[Wally Schirra|Schirra]], [[Deke Slayton|Slayton]], [[John Glenn|Glenn]] and [[Gordon Cooper|Cooper]], 1962]]
NASA announced the following seven astronauts – known as the [[Mercury Seven]] – on April 9, 1959:{{sfn|Alexander & al.|1966|p=164}}{{sfn|Alexander & al.|1966|p=640}}

{| class="wikitable sortable"
|-
! Name
! Launch
! Rank
! Unit
! Born
! Died
|-
| data-sort-value="Carpenter, Scott" | [[M. Scott Carpenter]]
| May 24, 1962
| [[Lieutenant (navy)|Lieutenant]]
| [[United States Navy|USN]]
| 1925
| 2013
|-
| data-sort-value="Cooper, Gordon" |[[L. Gordon Cooper]]
| May 15, 1963
| [[Captain (United States O-3)|Captain]]
| [[United States Air Force|USAF]]
| 1927
| 2004
|-
| data-sort-value="Glenn, John" |[[John H. Glenn, Jr.]]
| February 20, 1962
| [[Major (United States)|Major]]
| [[United States Marine Corps|USMC]]
| 1921
| 2016
|-
| data-sort-value="Grissom, Gus" |[[Virgil I. Grissom]]
| July 21, 1961
| [[Captain (United States O-3)|Captain]]
| USAF
| 1926
| 1967
|-
| data-sort-value="Schirra, Wally" |[[Walter M. Schirra, Jr.]]
| October 3, 1962
| [[Lieutenant commander (United States)|Lt Commander]]
| USN
| 1923
| 2007
|-
| data-sort-value="Shepard, Alan" |[[Alan B. Shepard, Jr.]]
| May 5, 1961
| [[Lieutenant commander (United States)|Lt Commander]]
| USN
| 1923
| 1998
|-
| data-sort-value="Slayton, Deke" |[[Donald K. Slayton]]
| 
| [[Major (United States)|Major]]
| USAF
| 1924
| 1993
|}

Alan Shepard became the first American in space by making a suborbital flight on May 5, 1961.{{sfn|Alexander & al.|1966|p=341}} [[Mercury-Redstone 3]], Shepard's 15 minute and 28 second flight of the ''Freedom 7'' capsule demonstrated the ability to withstand the high [[g-force]]s of launch and [[Atmospheric entry|atmospheric re-entry]]. Shepard later went on to fly in the [[Apollo program]] and became the only Mercury astronaut to walk on the Moon on [[Apollo 14]].{{sfn|Catchpole|2001|p=445}}<ref>Dunbar, B. (2015, May 12). Who was Alan shepherd? Retrieved April 22, 2021, from https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/who-was-alan-shepard-k4.html</ref>

[[Gus Grissom]] became the second American in space on [[Mercury-Redstone 4]] on July 21, 1961. After the splashdown of ''Liberty Bell 7'', the side hatch opened and caused the capsule to sink although Grissom was able to be safely recovered. His flight also gave NASA the confidence to move on to orbital flights. Grissom went on to participate in the Gemini and Apollo programs, but died in January 1967 during a pre-launch test for [[Apollo 1]].{{sfn|Catchpole|2001|p=442}}<ref>Documents – human Space Flight: A record of ACHIEVEMENT, 1961 – 1998. (n.d.). Retrieved April 22, 2021, from https://history.nasa.gov/SP-4225/documentation/hsf-record/hsf.htm#mercury</ref>

John Glenn became the first American to orbit the Earth on [[Mercury-Atlas 6]] February 20, 1962. During the flight, the spacecraft ''Friendship 7'' experienced issues with its automatic control system but Glenn was able to manually control the spacecraft's attitude. He quit NASA in 1964, when he came to the conclusion that he likely would not be selected for any Apollo missions, and was later elected to the US Senate, serving from 1974 to 1999. During his tenure, he returned to space in 1998 as a Payload Specialist aboard [[STS-95]].{{sfn|Catchpole|2001|pp=440,441}}<ref>Dunbar, B. (2016, December 05). Profile of John Glenn. Retrieved April 22, 2021, from https://www.nasa.gov/content/profile-of-john-glenn</ref>

Scott Carpenter was the second astronaut in orbit and flew on [[Mercury-Atlas 7]] on May 24, 1962. The spaceflight was essentially a repeat of Mercury-Atlas 6, but a targeting error during re-entry took ''Aurora 7'' 250 miles (400&nbsp;km) off-course, delaying recovery. Afterwards, he joined the Navy's "Man in the Sea" program and is the only American to be both an [[astronaut]] and an [[aquanaut]].<ref>Fox, S. (2015, February 20). Scott carpenter, 1925–2013. Retrieved April 22, 2021, from https://www.nasa.gov/astronautprofiles/carpenter {{Webarchive|url=https://web.archive.org/web/20211104004807/https://www.nasa.gov/astronautprofiles/carpenter/ |date=November 4, 2021 }}</ref>{{sfn|Catchpole|2001|pp=446–447}} Carpenter's Mercury flight was his only trip into space.

Wally Schirra flew aboard ''Sigma 7'' on [[Mercury-Atlas 8]] on October 3, 1962. The mission's main goal was to show development of environmental controls or life-support systems that would allow for safety in space, thus being a flight mainly focused on technical evaluation, rather than scientific experimentation. The mission lasted 9 hours and 13 minutes, setting a new US flight duration record.<ref>40Th anniversary of Mercury 7: WALTER Marty Schirra, jr. (n.d.). Retrieved April 22, 2021, from https://history.nasa.gov/40thmerc7/schirra.htm</ref> In December 1965, Schirra flew on [[Gemini 6A]], achieving the first ever [[space rendezvous]] with sister spacecraft [[Gemini 7]]. Three years later, he commanded the first crewed Apollo mission, [[Apollo 7]], becoming the first astronaut to fly three times and the only person to fly in the Mercury, Gemini, and Apollo programs.

Gordon Cooper made the last flight of Project Mercury with [[Mercury-Atlas 9]] on May 15, 1963. His flight onboard ''Faith 7'' set another US endurance record with a 34-hour and 19 minute flight duration, and 22 completed orbits. This mission marks the last time an American was launched alone to conduct an entirely solo orbital mission. Cooper later went on to participate in [[Project Gemini]] where he once again beat the endurance record during [[Gemini 5]].<ref>Administrator, N. (2015, February 27). Remembering Gordon Cooper. Retrieved April 22, 2021, from https://www.nasa.gov/multimedia/imagegallery/image_feature_218.html</ref>{{sfn|Alexander & al.|1966|pp=640–641}}

Deke Slayton was grounded in 1962 due to a heart condition, but remained with NASA and was appointed senior manager of the Astronaut Office and later additionally assistant director of Flight Crew Operations at the beginning of [[Project Gemini]]. On March 13, 1972, after doctors confirmed he no longer had a coronary condition, Slayton returned to flight status and the next year was assigned to the [[Apollo–Soyuz Test Project]], which successfully flew in 1975 with Slayton as the docking module pilot. After the ASTP, he managed the Space Shuttle Program's [[Approach and Landing Tests]] (ALT) and Orbital Flight Tests (OFT) before retiring from NASA in 1982.

One of the astronauts' tasks was publicity; they gave interviews to the press and visited project manufacturing facilities to speak with those who worked on Project Mercury.{{sfn|Catchpole|2001|p=99}} The press was especially fond of John Glenn, who was considered the best speaker of the seven.{{sfn|Catchpole|2001|p=96}} They sold their personal stories to [[Life (magazine)|''Life'']] magazine which portrayed them as 'patriotic, God-fearing family men.'{{sfn|Catchpole|2001|p=100}} ''Life'' was also allowed to be at home with the families while the astronauts were in space.{{sfn|Catchpole|2001|p=100}} During the project, Grissom, Carpenter, Cooper, Schirra and Slayton stayed with their families at or near Langley Air Force Base; Glenn lived at the base and visited his family in Washington DC on weekends. Shepard lived with his family at [[Naval Air Station Oceana]] in Virginia.

Other than Grissom, who was killed in the 1967 [[Apollo 1]] fire, the other six survived past retirement and died between 1993 and 2016.{{sfn|Catchpole|2001|p=97}}

{{hidden begin|title={{center|Astronauts' assignments}}|style=border:solid 1px #aaa;background:#F9F9F9;padding-left:10px;}}
<gallery mode="packed">
AstronautAssignmentsChart-Mercury7.PNG|Mercury 7 astronaut assignments. Schirra had the most flights with three; Glenn, though being the first to leave NASA, had the last with a [[STS-95|Space Shuttle mission]] in 1998.<ref name=Glenn1998/> Shepard was the only one to walk on the Moon.
</gallery>
{{clear}}
{{hidden end}}

===Selection and training===
Prior to Project Mercury, there was no protocol for selecting astronauts, so NASA would set a far-reaching precedent with both their selection process and initial choices for astronauts. At the end of 1958, various ideas for the selection pool were discussed privately within the national government and the civilian space program, and also among the public at large. Initially, there was the idea to issue a widespread public call to volunteers. Thrill-seekers such as rock climbers and acrobats would have been allowed to apply, but this idea was quickly shot down by NASA officials who understood that an undertaking such as space flight required individuals with professional training and education in flight engineering. By late 1958, NASA officials decided to move forward with test pilots being the heart of their selection pool.<ref name="NASA">{{cite web|last1=Dunbar|first1=Brian|title=Project Mercury Overview – Astronaut Selection|url=https://www.nasa.gov/mission_pages/mercury/missions/summary.html|website=nasa.gov|date=March 17, 2015 |publisher=NASA|access-date=24 April 2018}}</ref> On President Eisenhower's insistence, the group was further narrowed down to active duty military [[test pilot]]s, which set the number of candidates at 508.{{sfn|Alexander & al.|1966|pp=160–161}} These candidates were [[USN]] or [[USMC]] [[United States Naval Aviator|naval aviation pilots]] (NAPs), or [[USAF]] [[U.S. Air Force aeronautical rating#USAF rating requirements|pilots of Senior or Command rating]]. These aviators had long military records, which would give NASA officials more background information on which to base their decisions. Furthermore, these aviators were skilled in flying the most advanced aircraft to date, giving them the best qualifications for the new position of astronaut.<ref name="NASA"/> During this time, women were banned from flying in the military and so could not successfully qualify as test pilots. This meant that no female candidates could earn consideration for the title of astronaut. Civilian NASA [[X-15]] pilot [[Neil Armstrong]] was also disqualified, though he had been selected by the US Air Force in 1958 for its [[Man in Space Soonest]] program, which was replaced by Mercury.{{sfn|Hansen|2005|p=173}} Although Armstrong had been a combat-experienced NAP during the Korean War, he left active duty in 1952.{{sfn|Catchpole|2001|p=92}}{{refn|group=n|Armstrong left the Navy as a [[Lieutenant (junior grade)|Lieutenant, Junior Grade]] in the [[United States Navy Reserve|US Naval Reserve]], until resigning his commission 1960.{{sfn|Hansen|2005|p=118}}}} Armstrong became NASA's first civilian astronaut in 1962 when he was selected for NASA's second group,{{sfn|Hansen|2005|pp=201–202}} and [[Apollo 11|became the first man on the Moon]] in 1969.{{sfn|Nelson|2009|p=17}}

It was further stipulated that candidates should be between 25 and 40 years old, no taller than {{convert|5|ft|11|in|m|abbr=on}}, and hold a college degree in a [[Science, technology, engineering, and mathematics|STEM]] subject.{{sfn|Catchpole|2001|p=92}} The college degree requirement excluded the USAF's [[Bell X-1|X-1]] pilot, then-Lt Col (later Brig Gen) [[Chuck Yeager]], the first person to exceed the [[speed of sound]].{{sfn|Catchpole|2001|pp=92–93}} He later became a critic of the project, ridiculing the civilian space program, labeling astronauts as "spam in a can."<ref>{{cite web|last1=Cloer|first1=Dan|title=Alan B. Shepard, Jr.: Spam in a Can?|url=http://www.vision.org/visionmedia/biography/alan-b-shepard/17449.aspx|website=vision.org|publisher=Vision|access-date=24 April 2018}}</ref> John Glenn did not have a college degree either, but used influential friends to make the selection committee accept him.{{sfn|Catchpole|2001|p=440}} USAF Capt. (later Col.) [[Joseph Kittinger]], a USAF fighter pilot and stratosphere balloonist, met all the requirements but preferred to stay in his contemporary project.{{sfn|Catchpole|2001|pp=92–93}} Other potential candidates declined because they did not believe that human spaceflight had a future beyond Project Mercury.{{sfn|Catchpole|2001|pp=92–93}}{{refn|At the beginning of the project both President Eisenhower and NASA's first administrator, T. K. Glennan, believed that the US would put the first man in space, and that this would be the end of the Space Race.{{sfn|Catchpole|2001|p=407}}|group=n}} From the original 508, 110 candidates were selected for an interview, and from the interviews, 32 were selected for further physical and mental testing.{{sfn|Catchpole|2001|p=93}} Their health, vision, and hearing were examined, together with their tolerance to noise, vibrations, g-forces, personal isolation, and heat.{{sfn|Catchpole|2001|p=98}}<ref>[[David Minard|Minard, D.]] (1964). Work Physiology. Archives of Environmental Health. 8(3): 427–436.</ref> In a special chamber, they were tested to see if they could perform their tasks under confusing conditions.{{sfn|Catchpole|2001|p=98}} The candidates had to answer more than 500 questions about themselves and describe what they saw in different images.{{sfn|Catchpole|2001|p=98}} Navy Lt (later Capt) [[Jim Lovell]], who was later an astronaut in the [[Project Gemini|Gemini]] and [[Apollo program]]s, did not pass the physical tests.{{sfn|Catchpole|2001|pp=92–93}} After these tests it was intended to narrow the group down to six astronauts, but in the end it was decided to keep seven.{{sfn|Catchpole|2001|p=94}}

The astronauts went through a training program covering some of the same exercises that were used in their selection.{{sfn|Catchpole|2001|pp=103–110}} They simulated the g-force profiles of launch and reentry in a centrifuge at the [[Naval Air Development Center]], and were taught special breathing techniques necessary when subjected to more than 6 g.{{sfn|Catchpole|2001|p=104}} Weightlessness training took place in aircraft, first on the rear seat of a two-seater fighter and later inside converted and padded [[cargo aircraft]].{{sfn|Catchpole|2001|p=105}} They practiced gaining control of a spinning spacecraft in a machine at the [[Lewis Flight Propulsion Laboratory]] called the Multi-Axis Spin-Test Inertia Facility (MASTIF), by using an [[Spacecraft attitude control|attitude control]]ler handle simulating the one in the spacecraft.<ref>{{cite web| title =Gimbal Rig Mercury Astronaut Trainer | publisher =NASA| date =9 June 2008| url =http://www.nasa.gov/centers/glenn/about/history/mastif.html#.VIy1TnvAuJw|access-date = 13 December 2014 }}</ref><ref>{{YouTube| M3m5npzgVLY | "Gimbal Rig" }}</ref> A further measure for finding the right attitude in orbit was star and Earth recognition training in planetaria and simulators.{{sfn|Catchpole|2001|pp=105, 109}} Communication and flight procedures were practiced in flight simulators, first together with a single person assisting them and later with the [[Mission Control Center (NASA)|Mission Control Center]].{{sfn|Catchpole|2001|p=111}} Recovery was practiced in pools at [[Langley Air Force Base|Langley]], and later at sea with frogmen and helicopter crews.{{sfn|Alexander & al.|1966|p=346}}

<gallery mode="packed">
Astronaut Walter M. Schirra Prepares to Test Gravitational Stress.jpg|G-force training, [[Naval Air Warfare Center Warminster|Johnsville]], 1960
Mercury Astronauts in Weightless Flight on C-131 Aircraft - GPN-2002-000039.jpg|Weightlessness simulation in a [[C-131]]
Project Mercury AWT Gimbaling Rig close.jpg|MASTIF at [[Glenn Research Center|Lewis Research Center]]
Shepard in trainer before launch.jpg|Flight trainer at Cape Canaveral
B60 285b.jpg|Egress training at [[Langley Research Center|Langley]]
</gallery>
{{clear}}

==Mission profile==
===Suborbital missions===
[[File:Mr3-flight-timeline-simple-2.png|thumb|upright=1.2|Profile. See timetable for explanation. Dashed line: region of weightlessness.]]

A Redstone rocket was used to boost the capsule for 2 minutes and 30 seconds to an altitude of {{convert|32|nmi|km}}; the capsule continued ascending on a ballistic curve after booster separation.{{sfn|Unknown|1961a|p=7}}{{sfn|Catchpole|2001|pp=208, 250}} The launch escape system was jettisoned at the same time. At the top of the curve, the spacecraft's retrorockets were fired for testing purposes; they were not necessary for reentry because orbital speed had not been attained. The spacecraft landed in the Atlantic Ocean.{{sfn|Catchpole|2001|pp=250, 308}} The suborbital mission took about 15 minutes, had an apogee altitude of {{convert|102|-|103|nmi|km|sp=us}}, and a downrange distance of {{convert|262|nmi|km|sp=us}}.{{sfn|Alexander & al.|1966|pp=640–641}}{{sfn|Catchpole|2001|p=475}} From the time of booster-spacecraft separation until reentry where air started to slow down the spacecraft, the pilot would experience weightlessness as shown on the image.{{refn|group=n|With the exception of the 20 seconds of retrofire during which the pilot would experience g-force.}} The recovery procedure would be the same as an orbital mission.[AS]

{| class="wikitable collapsible collapsed"
|-
!colspan="2" | Timetable (mm:ss)
|-
| style="text-align:right;"|0:00|| Launch
|-
| style="text-align:right;"| 2:22|| Launch vehicle cut-off and tower separation
|-
| style="text-align:right;"| 2:32|| Spacecraft separation
|-
| style="text-align:right;"| 2:37|| Turnaround
|-
| style="text-align:right;"| 5:14|| Retrofire
|-
| style="text-align:right;"| 6:14|| Retropack jettisoned
|-
| style="text-align:right;"| 7:48|| Reentry
|-
| style="text-align:right;"| 9:38|| Drogue deployed
|-
| style="text-align:right;"| 10:15|| Main chute deployed
|-
| style="text-align:right;"| 15:22|| Landing
|}

===Orbital missions===

[[File:Launch-complex-14.png|thumb|upright=1.2|Launch Complex 14 just before launch (service tower rolled aside). Preparations for launch were made in the blockhouse.]]

Preparations for a mission started a month in advance with the selection of the primary and back-up astronaut; they would practice together for the mission.{{sfn|Catchpole|2001|p=110}} For three days prior to launch, the astronaut went through a special diet to minimize his need for [[defecation|defecating]] during the flight.{{sfn|Catchpole|2001|p=278}} On the morning of the trip he typically ate a steak breakfast.{{sfn|Catchpole|2001|p=278}} After having sensors applied to his body and being dressed in the pressure suit, he started breathing pure oxygen to prepare him for the atmosphere of the spacecraft.{{sfn|Catchpole|2001|p=280}} He arrived at the launch pad, took the elevator up the launch tower and entered the spacecraft two hours before launch.{{sfn|Catchpole|2001|p=188}}{{refn|group=n|Inside the spacecraft the other astronauts had usually prepared a practical joke, such as a sign saying "No handball playing".{{sfn|Catchpole|2001|p=281}}}} Once the astronaut was secured inside, the hatch was bolted, the launch area evacuated and the mobile tower rolled back.{{sfn|Catchpole|2001|p=281}} After this, the launch vehicle was filled with liquid oxygen.{{sfn|Catchpole|2001|p=281}} The entire procedure of preparing for launch and launching the spacecraft followed a time table called the countdown. It started a day in advance with a pre-count, in which all systems of the launch vehicle and spacecraft were checked. After that followed a 15-hour hold, during which pyrotechnics were installed. Then came the main countdown which for orbital flights started 6½ hours before launch (T – 390 min), counted backwards to launch (T = 0) and then forward until orbital insertion (T + 5 min).{{sfn|Catchpole|2001|p=188}}{{refn|group=n|Countdown was controlled from the blockhouse at the Launch Complex until 2 min. before launch then it was transferred to Mission Control Center. The countdown of the last 10 sec. before launch would be given to the astronaut by one of the others and included on TV transmissions which had already started.{{sfn|Catchpole|2001|p=282}}}}

[[File:Vol-Atlas-Mercury.png|thumb|upright=0.9|Launch and reentry profiles: A-C: launch; D: orbital insertion; E-K: reentry and landing]]

On an orbital mission, the Atlas' rocket engines were ignited four seconds before lift-off. The launch vehicle was held to the ground by clamps and then released when sufficient thrust was built up at lift-off ('''A''').{{sfn|Catchpole|2001|pp=188, 242}} After 30 seconds of flight, the point of maximum [[dynamic pressure]] against the vehicle was reached, at which the astronaut felt heavy vibrations.{{sfn|Catchpole|2001|p=340}} After 2 minutes and 10 seconds, the two outboard booster engines shut down and were released with the aft skirt, leaving the center sustainer engine running ('''B''').{{sfn|Catchpole|2001|p=188}} At this point, the launch escape system was no longer needed, and was separated from the spacecraft by its jettison rocket ('''C''').{{sfn|Catchpole|2001|p=132}}{{refn|In the event of a launch abort before this point, the launch escape system would fire its main rocket for one second, pulling the spacecraft and astronaut away from the launch vehicle and a possible explosion.{{sfn|Catchpole|2001|p=179}} At this point, the spacecraft could be separated from the launch vehicle and land using its parachute.{{sfn|Catchpole|2001|p=180}}|group=n}} The space vehicle moved gradually to a horizontal attitude until, at an altitude of {{convert|87|nmi|km|sp=us}}, the sustainer engine shut down and the spacecraft was inserted into orbit ('''D''').{{sfn|Unknown|1962|p=46}} This happened after 5 minutes and 10 seconds in a direction pointing east, whereby the spacecraft would gain speed from the rotation of the Earth.{{sfn|Catchpole|2001|pp=188, 460}}{{refn|group=n|The direction of insertion was east and slightly to the north, meaning that, on a three-orbit flight, the tracking network was used optimally and a landing could take place in the North Atlantic Ocean.{{sfn|Alexander & al.|1966|p=215}}}} Here the spacecraft fired the three posigrade rockets for a second to separate it from the launch vehicle.{{sfn|Catchpole|2001|p=133}}{{refn|The sustainer would disintegrate and fall down; after the launch of ''Friendship 7'' a part of the sustainer was found in South Africa.{{sfn|Grimwood|1963|p=164}}|group=n}} Just before orbital insertion and sustainer engine cutoff, g-loads peaked at 8 g (6 g for a suborbital flight).{{sfn|Catchpole|2001|p=340}}{{sfn|Unknown|1961|p=10}} In orbit, the spacecraft automatically turned 180°, pointed the retropackage forward and its nose 14.5° downward and kept this attitude for the rest of the orbital phase to facilitate communication with the ground.{{sfn|Alexander & al.|1966|p=333}}{{sfn|Catchpole|2001|p=120}}{{refn|group=n|The capsule's tendency to drift was countered automatically by the attitude control system (ASCS) which used small hydrogen peroxide thrusters. To save fuel, however, the spacecraft would be allowed to drift from time to time, especially on longer missions.{{sfn|Alexander & al.|1966|pp=195, 450}}}}

Once in orbit, it was not possible for the spacecraft to change its [[trajectory]] except by initiating reentry.{{sfn|Catchpole|2001|p=462}} Each orbit would typically take 88 minutes to complete.{{sfn|Catchpole|2001|p=324}} The lowest point of the orbit, called [[perigee]], was at about {{convert|87|nmi|km|sp=us}} altitude, and the highest point, called [[apogee]], was about {{convert|150|nmi|km|sp=us}} altitude.{{sfn|Catchpole|2001|p=475}} When leaving orbit ('''E'''), the angle of retrofire was 34° downward from the flight path angle.{{sfn|Alexander & al.|1966|p=333}} Retrorockets fired for 10 seconds each ('''F''') in a sequence where one started 5 seconds after the other.{{sfn|Catchpole|2001|p=133}}{{sfn|Unknown|1961|p=9}} During reentry ('''G'''), the astronaut would experience about 8 g (11–12 g on a suborbital mission).{{sfn|Alexander & al.|1966|p=574}} The temperature around the heat shield rose to {{convert|3000|°F|abbr=on|sigfig=2}} and at the same time, there was a two-minute radio blackout due to [[ionization]] of the air around the spacecraft.{{sfn|Unknown|1962|p=9}}{{sfn|Catchpole|2001|p=134}}

After reentry, a small, drogue parachute ('''H''') was deployed at {{convert|21000|ft|abbr=on}} for stabilizing the spacecraft's descent.{{sfn|Catchpole|2001|p=147}} The main parachute ('''I''') was deployed at {{convert|10000|ft|abbr=on}} starting with a narrow opening that opened fully in a few seconds to lessen the strain on the lines.{{sfn|Alexander & al.|1966|p=356}} Just before hitting the water, the landing bag inflated from behind the heat shield to reduce the force of impact ('''J''').{{sfn|Alexander & al.|1966|p=356}} Upon landing the parachutes were released.{{sfn|Catchpole|2001|p=144}} An antenna ('''K''') was raised and sent out signals that could be traced by ships and [[helicopter]]s.{{sfn|Catchpole|2001|p=144}} Further, a green marker dye was spread around the spacecraft to make its location more visible from the air.{{sfn|Catchpole|2001|p=144}}{{refn|group=n|[[Radar chaff]] and a [[SOFAR bomb]] which could be detected by the recovery ship's [[hydrophone]] were eliminated as unnecessary measures after the first orbital flight.{{sfn|Alexander & al.|1966|p=445}}}} [[Frogmen]] brought in by helicopters inflated a collar around the craft to keep it upright in the water.{{sfn|Catchpole|2001|p=166}}{{refn|group=n|The collar was not ready for suborbital missions.{{sfn|Catchpole|2001|p=166}}}} The recovery helicopter hooked onto the spacecraft and the astronaut blew the escape hatch to exit the capsule.{{sfn|Catchpole|2001|pp=144–145}} He was then hoisted aboard the helicopter that finally brought both him and the spacecraft to the ship.{{refn|It was also possible to exit the capsule through the nose cylinder; only Carpenter did this.{{sfn|Alexander & al.|1966|p=143}}{{sfn|Catchpole|2001|p=147}} | group=n}}

<gallery mode="packed">
Mercury profile.jpg|Mercury crewed launches
Glenn62.jpg|[[John Glenn]] in orbit, 1962 (Mercury-Atlas 6)
Shepard Hoisted into Recovery Helicopter - GPN-2000-001361-crop.jpg|[[Alan Shepard]]'s 1961 recovery seen from helicopter (Mercury-Redstone 3)
</gallery>
{{clear}}

==Ground control==
[[File:Mercury Control crop.jpg|thumb|alt=A look inside the Mercury Control Center, Cape Canaveral, Florida. Dominated by the control board showing the position of the spacecraft above ground|Inside Control Center at Cape Canaveral (Mercury-Atlas 8)]]
The number of personnel supporting a Mercury mission was typically around 18,000, with about 15,000 people associated with recovery.{{sfn|Alexander & al.|1966|p=508}}{{sfn|Unknown|1962|p=3}}{{refn| [[T. J. O'Malley]] pushed the button to launch Glenn<ref>{{cite news|title=Thomas J. O'Malley, Who Helped Launch Glenn Into Orbit, Dies at 94|url=https://www.nytimes.com/2009/11/12/us/12omalley.html|date=November 12, 2009|first=Dennis|last=Hevesi|work=The New York Times }}</ref> while the Site Manager and Launch Conductor at Complex 14, Calvin D. Fowler, pushed the button to launch Carpenter, Schirra, and Cooper.<ref>{{cite web|url=https://richesmi.cah.ucf.edu/omeka/items/show/4975|title=Letter from General Ben I. Funk to Dr. Calvin D. Fowler (May 14, 1963)|publisher=University of Central Florida|access-date=February 1, 2023}}</ref>|group=n}} Most of the others followed the spacecraft from the World Wide Tracking Network, a chain of 18 stations placed around the equator, which was based on a network used for satellites and made ready in 1960.{{sfn|Catchpole|2001|pp=124, 461–462}} It collected data from the spacecraft and provided two-way communication between the astronaut and the ground.{{sfn|Catchpole|2001|p=117}} Each station had a range of {{convert|1300|km|nmi|order=flip|sp=us}} and a pass typically lasted 7 minutes.{{sfn|Catchpole|2001|pp=121, 126}} Mercury astronauts on the ground would take the role of Capsule Communicator, or CAPCOM, who communicated with the astronaut in orbit.{{sfn|Alexander & al.|1966|p=360}}{{sfn|Alexander & al.|1966|p=479}}{{refn|group=n|Occasionally this communication was broadcast on live TV while the spacecraft was passing over the United States.}} Data from the spacecraft were sent to the ground, processed at the Goddard Space Center by a redundant pair of transistorized [[IBM 7090]] computers<ref name="NASAComp8" /> and relayed to the [[Mercury Control Center]] at Cape Canaveral.{{sfn|Catchpole|2001|p=118}} In the Control Center, the data were displayed on boards on each side of a world map, which showed the position of the spacecraft, its [[ground track]] and the place it could land in an emergency within the next 30 minutes.{{sfn|Catchpole|2001|p=120}}

Other computers associated with ground control for Mercury included a vacuum-tube-based [[IBM 709]] system in Cape Canaveral which determined whether a mid-launch abort might be needed and where an aborting capsule would land, another IBM 709 in Bermuda which served as backup for the two IBM 7090 transistor-based machines at Goddard, and a Burroughs-GE system which provided radio guidance for the Atlas during launch.<ref name="NASAComp8" />

The World Wide Tracking Network went on to serve subsequent space programs, until it was replaced by a satellite relay system in the 1980s.{{sfn|Catchpole|2001|p=409}} Mission Control Center was moved from Cape Canaveral to [[Houston]] in 1965.{{sfn|Catchpole|2001|p=88}}

{{hidden begin|title={{center|Tracking network}}|style=border:solid 1px #aaa;background:#F9F9F9;padding-left:10px;}}
<gallery mode="packed">
Mercury Tracking Network 2.png|Ground track and tracking stations for Mercury-Atlas 8. Spacecraft starts from Cape Canaveral in Florida and moves east; each new orbit-track is displaced to the left due to the rotation of the Earth. It moves between latitudes 32.5° north and 32.5° south.{{sfn|Catchpole|2001|p=128}} Key: 1–6: orbit number. Yellow: launch. Black dot: tracking station. Red: range of station; Blue: landing.
</gallery>
{{clear}}
{{hidden end}}

==Flights==
<div style="float: right; position: relative;width:400px; margin: 0em 0em 0.5em 2em;">
[[File:Mercury-splash-down.png|thumb|400px|Project Mercury landing sites]]
{{Image label|x=0.700 |y=0.180 |scale=400|text=<span style="color:gray;">/</span>}}
{{Image label|x=0.690 |y=0.150 |scale=400|text=<span style="background:white; color:gray; font-size:11px; padding-left:2px;">Cape Canaveral</span>}}
{{Image label|x=0.100 |y=0.275 |scale=400|text=<span style="color:gray;font-size:11px;">Hawaii</span>}}
{{Image label|x=0.725 |y=0.190 |scale=400|text=[[File:City locator 23.svg|10px]]}}
{{Image label|x=0.610 |y=0.210 |scale=400|text=<span style="font-size:11px;">''[[Freedom 7]]''</span>}}
{{Image label|x=0.730 |y=0.185 |scale=400|text=[[File:City locator 23.svg|10px]]}}
{{Image label|x=0.755 |y=0.185 |scale=400|text=<span style="font-size:11px;">''[[Liberty Bell 7]]''</span>}}
{{Image label|x=0.790 |y=0.235 |scale=400|text=[[File:City locator 23.svg|10px]]}}
{{Image label|x=0.815 |y=0.225 |scale=400|text=<span style="font-size:11px;">''[[Friendship 7]]''</span>}}
{{Image label|x=0.825 |y=0.250 |scale=400|text=[[File:City locator 23.svg|10px]]}}
{{Image label|x=0.850 |y=0.255 |scale=400|text=<span style="font-size:11px;">''[[Aurora 7]]''</span>}}
{{Image label|x=0.025 |y=0.195 |scale=400|text=[[File:City locator 23.svg|10px]]}}
{{Image label|x=0.050 |y=0.195 |scale=400|text=<span style="font-size:11px;">''[[Mercury-Atlas 8|Sigma 7]]''</span>}}
{{Image label|x=0.020 |y=0.225 |scale=400|text=[[File:City locator 23.svg|10px]]}}
{{Image label|x=0.045 |y=0.230 |scale=400|text=<span style="font-size:11px;">''[[Faith 7]]''</span>}}
</div>
On April 12, 1961, the Soviet [[cosmonaut]] [[Yuri Gagarin]] became the first person in space on an orbital flight.{{sfn|Alexander & al.|1966|p=332}} Alan Shepard became the first American in space on a suborbital flight three weeks later, on May 5, 1961.{{sfn|Alexander & al.|1966|p=341}} John Glenn, the third Mercury astronaut to fly, became the first American to reach orbit on February 20, 1962, but only after the Soviets had launched a second cosmonaut, [[Gherman Titov]], into a day-long flight in August 1961.{{sfn|Alexander & al.|1966|pp=377, 422}} Three more Mercury orbital flights were made, ending on May 16, 1963, with a day-long, 22 orbit flight.{{sfn|Alexander & al.|1966|pp=640–641}} However, the Soviet Union ended its [[Vostok programme|Vostok program]] the next month, with the human spaceflight endurance record set by the 82-orbit, almost 5-day [[Vostok 5]] flight.{{sfn|Catchpole|2001|p=476}}

===Crewed===

All of the six crewed Mercury flights were successful, though some planned flights were canceled during the project (see below).{{sfn|Alexander & al.|1966|pp=640–641}} The main medical problems encountered were simple personal [[hygiene]], and post-flight [[orthostatic hypotension|symptoms of low blood pressure]].{{sfn|Alexander & al.|1966|p=508}} The launch vehicles had been tested through uncrewed flights, therefore the numbering of crewed missions did not start with 1.{{sfn|Alexander & al.|1966|pp=638–641}} Also, there were two separately numbered series: MR for "Mercury-Redstone" (suborbital flights), and MA for "Mercury-Atlas" (orbital flights). These names were not popularly used, since the astronauts followed a pilot tradition, each giving their spacecraft a name. They selected names ending with a "7" to commemorate the seven astronauts.{{sfn|Catchpole|2001|p=132}}{{sfn|Alexander & al.|1966|p=640}} Spacecraft production numbers don't match the mission order, with some capsules being reserved as backup or used in tests.<ref name=":0">{{Cite web |title=Project Mercury - A Chronology. Appendix 6 |url=https://history.nasa.gov/SP-4001/app6.htm |access-date=2023-10-20 |website=history.nasa.gov}}</ref> Times given are [[UTC|Coordinated Universal Time]], local time + 5 hours. MA = Mercury-Atlas, MR = Mercury-Redstone, LC = Launch Complex.{{refn |Alexander & al., 1966, pp. 638–641. | group = n }}

{| class="wikitable sortable"
|-
! rowspan=2| Mission
! rowspan="2" |Spacecraft No.
! rowspan="2" | Call-sign
! rowspan=2| Pilot
! colspan=2 class="unsortable"| Launch 
! rowspan=2| Duration
! rowspan=2| Orbits
! rowspan=2| Apogee<br />mi (km)
! rowspan=2| Perigee<br />mi (km)
! rowspan=2| Max. velocity <br />mph (km/h)
! rowspan=2| Miss<br />mi (km)
|-
! time||site
|-
| [[Mercury-Redstone 3|MR-3]]
|7
| ''Freedom 7''
| [[Alan Shepard|Shepard]]
| style="text-align:right;" data-sort-value="1"|14:34 on May 5, 1961
| style="text-align:left;" |[[Cape Canaveral Air Force Station Launch Complex 5|LC-5]]
| style="text-align:right;" data-sort-value="1"|15 m 22 s
| style="text-align:right;"  |0
| style="text-align:right;"  |117 (188)
| style="text-align:center;" | —
| style="text-align:right;"  data-sort-value="6" | {{convert|5134|mph|abbr=values}}
| style="text-align:right;" data-sort-value="1"| 3.5 (5.6)
|-
| [[Mercury-Redstone 4|MR-4]]
|11
| ''Liberty Bell 7''
| [[Gus Grissom|Grissom]]
| style="text-align:right;" data-sort-value="2"|12:20 on Jul. 21, 1961
| style="text-align:left;" |LC-5
| style="text-align:right;" data-sort-value="2"|15 m 37 s
| style="text-align:right;" |0
| style="text-align:right;" |118 (190)
| style="text-align:center;" |—
| style="text-align:right;"  data-sort-value="5"|{{convert|5168|mph|abbr=values}}
| style="text-align:right;" data-sort-value="4"| 5.8 (9.3)
|-
| [[Mercury-Atlas 6|MA-6]]
|13
| ''Friendship 7''
| [[John Glenn|Glenn]]
| style="text-align:right;" data-sort-value="3"|14:47 on Feb. 20, 1962
| style="text-align:left;" |[[Cape Canaveral Air Force Station Launch Complex 14|LC-14]]
| style="text-align:right;"  data-sort-value="3"|4 h 55 m 23 s
| style="text-align:right;" |3
| style="text-align:right;" |162 (261)
| style="text-align:right;" |100 (161)
| style="text-align:right;"  data-sort-value="4"|{{convert|17544|mph|abbr=values}}
| style="text-align:right;" data-sort-value="5"| 46 (74)
|-
| [[Mercury-Atlas 7|MA-7]]
|18
| ''Aurora 7''
| [[Scott Carpenter|Carpenter]]
| style="text-align:right;" data-sort-value="4"|12:45 on May 24, 1962
| style="text-align:left;" |LC-14
| style="text-align:right;" data-sort-value="4"|4 h 56 m 5 s
| style="text-align:right;" |3
| style="text-align:right;" |167 (269)
| style="text-align:right;" |100 (161)
| style="text-align:right;" data-sort-value="2"|{{convert|17549|mph|abbr=values}}
| style="text-align:right;" data-sort-value="6"| 248 (400)
|-
| [[Mercury-Atlas 8|MA-8]]
|16
| ''Sigma 7''
| [[Wally Schirra|Schirra]]
| style="text-align:right;" data-sort-value="5"|12:15 on Oct. 3, 1962
| style="text-align:left;" |LC-14
| style="text-align:right;" data-sort-value="5"|9 h 13 m 15 s
| style="text-align:right;" |6
| style="text-align:right;" |176 (283)
| style="text-align:right;" |100 (161)
| style="text-align:right;"  data-sort-value="1"|{{convert|17558|mph|abbr=values}}
| style="text-align:right;" data-sort-value="2"| 4.6 (7.4)
|-
| [[Mercury-Atlas 9|MA-9]]
|20
| ''Faith 7''
| [[Gordon Cooper|Cooper]]
| style="text-align:right;" data-sort-value="6"|13:04 on May 15, 1963
| style="text-align:left;" |LC-14
| style="text-align:right;" data-sort-value="6"|1 d 10 h 19 m 49 s
| style="text-align:right;" | 22
| style="text-align:right;" | 166 (267)
| style="text-align:right;" | 100 (161)
| style="text-align:right;"  data-sort-value="3"|{{convert|17547|mph|abbr=values}}
| style="text-align:right;" data-sort-value="3"| 5.0 (8.1)
|}

{| class="wikitable collapsible collapsed"
|-
!colspan="2" | Remarks
|-
| {{Nowrap|Mercury-Redstone 3}}|| First American in space.{{sfn|Alexander & al.|1966|p=341}} Recovered by [[aircraft carrier|carrier]] [[USS Lake Champlain (CV-39)|USS ''Lake Champlain'']].{{sfn|Alexander & al.|1966|p=357}}
|-
| Mercury-Redstone 4|| Spacecraft sank during recovery when hatch unexpectedly blew off.{{sfn|Alexander & al.|1966|p=373}}{{refn |It was recovered in 1999.{{sfn|Catchpole|2001|pp=402–405}}| group = n }} Astronaut recovered by carrier [[USS Randolph (CV-15)|USS ''Randolph'']].{{sfn|Alexander & al.|1966|p=375}}
|-
| Mercury-Atlas 6|| First American in orbit.{{sfn|Alexander & al.|1966|p=422}} Retropack retained during reentry.{{sfn|Alexander & al.|1966|p=432}}{{refn|group=n|Launch of ''Friendship 7'' was postponed repeatedly during two months; a frustrated politician compared the spacecraft-Atlas combination to "a [[Rube Goldberg machine|Rube Goldberg device]] on top of a plumber's nightmare".{{sfn|Alexander & al.|1966|p=409, 411}}}} Recovered by [[destroyer]] [[USS Noa (DD-841)|USS ''Noa'']].{{sfn|Alexander & al.|1966|p=433}}
|-
| Mercury-Atlas 7|| Carpenter replaced Deke Slayton.{{sfn|Alexander & al.|1966|p=440}}{{refn|group=n|Carpenter's overshoot of the landing site was caused by a malfunction in the automatic stabilization, which meant that retrofire was out of line with the movement of the spacecraft{{sfn|Alexander & al.|1966|p=453-454}}}} Recovered by [[destroyer]] [[USS Farragut (DDG-37)|USS ''Farragut'']].{{sfn|Alexander & al.|1966|p=456}} Biggest miss.{{refn|During Carpenter's mission a seaplane from the US Air Force got to the landing site about 1½ hour ahead of the Navy ships and offered to pick him up.  This, however, was declined by the admiral in charge of Mercury recovery operations, which led to a Senate hearing about the incident.{{sfn|Alexander & al.|1966|p=457}}|group=n}}
|-
| Mercury-Atlas 8|| The flight closest to plan.{{sfn|Alexander & al.|1966|p=484}} Carried out maneuvering tests.{{sfn|Alexander & al.|1966|p=476}} Recovered by carrier [[USS Kearsarge (CV-33)|USS ''Kearsarge'']].{{sfn|Alexander & al.|1966|p=483}}
|-
| Mercury-Atlas 9|| First American in space for over a day.{{sfn|Alexander & al.|1966|p=487}} Last American solo mission.{{refn|group=n|Likely to be so according to Alexander & al.{{sfn|Alexander & al.|1966|p=506}}}} Recovered by USS ''Kearsarge''.{{sfn|Alexander & al.|1966|p=501}}
|-
| Recovery variations|| MA6) spacecraft and astronaut hoist onboard directly; MA8) spacecraft and astronaut towed by boat to ship; MA9) spacecraft with astronaut inside flown to ship.{{sfn|Alexander & al.|1966|pp=353,375,433,457,483–484,501}}
|}
<gallery mode="packed">
Kennedy, Johnson, and others watching flight of Astronaut Shepard on television, 05 May 1961.png|Shepard's flight watched on TV in the [[White House]]. May 1961.
Astronaut_John_Glenn_being_Honored_-_GPN-2000-000607.jpg|John Glenn honored by the President. February 1962
USS Kearsarge (CVS-33) crew spells out 'Mercury 9' on the flight deck, 15 May 1963 (GPN-2000-001403).jpg|USS ''Kearsarge'' with crew spelling Mercury-9. May 1963.
</gallery>
{{Clear}}

===Uncrewed and chimpanzee flights===
The 20 uncrewed flights used Little Joe, Redstone, and Atlas launch vehicles.{{sfn|Alexander & al.|1966|p=640}} They were used to develop the launch vehicles, launch escape system, spacecraft and tracking network.{{sfn|Alexander & al.|1966|pp=638–641}} One flight of a [[Scout (rocket family)|Scout rocket]] attempted to launch a specialized satellite equipped with Mercury communications components for testing the ground tracking network, but the booster failed soon after liftoff. The Little Joe program used seven airframes for eight flights, of which three were successful. The second Little Joe flight was named Little Joe 6, because it was inserted into the program after the first 5 airframes had been allocated.{{sfn|Catchpole|2001|p=231}}{{sfn|Catchpole|2001|p=278}} Production spacecraft and boilerplates were used for these test flights.<ref name=":0" /> 
{{sticky header}}
{| class="wikitable sortable sticky-header"
|-
! Mission{{refn | Source: Alexander & al., 1966, pp. 638–641 when nothing else is mentioned. | group = n }}
!Spacecraft No.
! Launch
! Duration
! class="unsortable" | Purpose
! Result
|-
| [[Little Joe 1]]
|Boilerplate
| style="text-align:right;" |August 21, 1959
| style="text-align:right;"  data-sort-value="000020" | 20 s
| Test of launch escape system during flight.
| Failure
|-
| [[Big Joe 1]]
|Big Joe Boilerplate
| style="text-align:right;" |September 9, 1959
| style="text-align:right;"  data-sort-value="001300" |13 m 00 s
| Test of heat shield and Atlas/spacecraft interface.
| Partial success
|-
| [[Little Joe 6]]
|Boilerplate
| style="text-align:right;" |October 4, 1959
| style="text-align:right;"  data-sort-value="000510" | 5 m 10 s
| Test of spacecraft aerodynamics and integrity.
| Partial success
|-
| [[Little Joe 1A]]
|Boilerplate
| style="text-align:right;" |November 4, 1959
| style="text-align:right;"  data-sort-value="000811" | 8 m 11 s
|Test of launch escape system during flight with boiler plate capsule.
| Partial success
|-
| [[Little Joe 2]]
|Boilerplate
| style="text-align:right;" |December 4, 1959
| style="text-align:right;"  data-sort-value="001106" |11 m 6 s
| Escape system test with primate at high altitude.
| Success
|-
| [[Little Joe 1B]]
|Boilerplate
| style="text-align:right;" |January 21, 1960
| style="text-align:right;"  data-sort-value="000835" |8 m 35 s
|Maximum-q abort and escape test with primate with boiler plate capsule.
| Success
|-
| [[Beach Abort]]
|1
| style="text-align:right;" |May 9, 1960
| style="text-align:right;"  data-sort-value="000131" |1 m 31 s
| Test of the off-the-pad abort system.
| Success
|-
| [[Mercury-Atlas 1]]
|4
| style="text-align:right;" |July 29, 1960
| style="text-align:right;"  data-sort-value="000318" |3 m 18 s
| Test of spacecraft / Atlas combination.
| Failure
|-
| [[Little Joe 5]]
|3
| style="text-align:right;" |November 8, 1960
| style="text-align:right;"  data-sort-value="000222" |2 m 22 s
| First Little Joe escape system test with a production spacecraft, at max-q.
| Failure
|-
| [[Mercury-Redstone 1]]
|2
| style="text-align:right;" |November 21, 1960
| style="text-align:right;"  data-sort-value="000002" |2 s
| Qualification of spacecraft / Redstone combination.
| Failure
|-
| [[Mercury-Redstone 1A]]
|2
| style="text-align:right;" |December 19, 1960
| style="text-align:right;"  data-sort-value="001545" |15 m 45 s
| Qualification of spacecraft / Redstone combination.
| Success
|-
| [[Mercury-Redstone 2]]
|5
| style="text-align:right;" |January 31, 1961
| style="text-align:right;"  data-sort-value="001639" |16 m 39 s
| Qualification of spacecraft with [[Ham (chimpanzee)|chimpanzee named Ham]].
| Success
|-
| [[Mercury-Atlas 2]]
|6
| style="text-align:right;" |February 21, 1961
| style="text-align:right;"  data-sort-value="001756" |17 m 56 s
| Qualified Mercury/Atlas interface.
| Success
|-
| [[Little Joe 5A]]
|14
| style="text-align:right;" |March 18, 1961
| style="text-align:right;"  data-sort-value="002348" |5 m 25 s
| Second test of escape system with a production Mercury spacecraft.
| Partial success
|-
| Nowrap|[[Mercury-Redstone BD]]
|Boilerplate
| style="text-align:right;" |March 24, 1961
| style="text-align:right;"  data-sort-value="000823" |8 m 23 s
| Final Redstone test flight.
| Success
|-
| [[Mercury-Atlas 3]]
|8
| style="text-align:right;" |April 25, 1961
| style="text-align:right;"  data-sort-value="000719" |7 m 19 s
| Orbital flight with robot astronaut.{{sfn|Alexander & al.|1966|p=335}}{{sfn|Catchpole|2001|p=275}}{{refn|A machine that produced the same heat, vapor and CO<sub>2</sub> as an astronaut.{{sfn|Catchpole|2001|p=309}}|group=n}}
| Failure
|-
| [[Little Joe 5B]]
|14
| style="text-align:right;" |April 28, 1961
| style="text-align:right;"  data-sort-value="000525" |5 m 25 s
| Third test of escape system with a production spacecraft.
| Success
|- style="background-color:#CDE;"
| [[Mercury-Atlas 4]]
|8
| style="text-align:right;" |September 13, 1961
| style="text-align:right;"  data-sort-value="014920" |1 h 49 m 20 s
| Test of environmental control system with robot astronaut in orbit.
| Success
|- style="background-color:#CDE;"
| [[Mercury-Scout 1]]
| -
| style="text-align:right;" |November 1, 1961
| style="text-align:right;"  data-sort-value="000044" |44 s
| Special satellite to test Mercury tracking network.
| Failure
|- style="background-color:#CDE;"
| [[Mercury-Atlas 5]]
|9
| style="text-align:right;" |November 29, 1961
| style="text-align:right;"  data-sort-value="032059" |3 h 20 m 59 s
| Test of environmental control system in orbit with [[Enos (chimpanzee)|chimpanzee named Enos]].
| Success
|}
{{legend|#CDE|After suborbital crewed flights}}
{| class="wikitable collapsible collapsed"
|-
! colspan="2"|Remarks
|-
| Little Joe 1
| Due to an electrical malfunction, the escape tower ignited ½ hour before launch and took the spacecraft with it, leaving the rocket on the ground.{{sfn|Alexander & al.|1966|p=208}}
|-
| Big Joe 1
| Actually the first Mercury-Atlas flight.{{sfn|Alexander & al.|1966|p=640}} Recovered by {{USS|Strong|DD-758|6}} 2,407&nbsp;km SE of Cape Canaveral.{{sfn|Alexander & al.|1966|pp=203–204}} Altitude: {{convert|65|mi|abbr=on}} Qualified ablative heatshield.{{sfn|Catchpole|2001|p=229}}
|-
| Little Joe 6
| No additional tests{{sfn|Alexander & al.|1966|p=209}}
|-
| Little Joe 1A
|The rescue tower rocket ignited 10 seconds too late.{{sfn|Alexander & al.|1966|p=210}} Recovered by {{USS|Opportune|ARS-41|6}} {{convert|11.5|mi|abbr=on}} SE of Wallops Island.{{sfn|Catchpole|2001|p=232}}
|-
| Little Joe 2
| Carried Sam, a [[rhesus macaque]].{{sfn|Alexander & al.|1966|p=210}} Recovered by {{USS|Borie|DD-704|6}} {{convert|194|mi|abbr=on}} SE of Wallops Island, Virginia; altitude: 53&nbsp;mi (85&nbsp;km).{{sfn|Catchpole|2001|pp=234, 474}}
|-
| Little Joe 1B
|Carried a female rhesus monkey named Miss Sam.{{sfn|Alexander & al.|1966|p=212}}
|-
| Beach Abort
|A production spacecraft with minimal equipment was lifted from the ground by the launch escape system alone at [[Wallops Island]]. It reached an apogee of {{convert|2465|ft|km|order=flip}} and was recovered after landing. Top velocity: {{convert|976|mph|m/s|order=flip}}. Total payload: 1,154&nbsp;kg.
|-
| Mercury-Atlas 1
| Exploded while passing through max-q.{{sfn|Alexander & al.|1966|p=276}} To save weight, the airframe had been made thinner since Big Joe, which led to a collapse. The next Atlas was strengthened by a temporary solution while the rest were made from the same specifications as Big Joe.{{sfn|Catchpole|2001|p=243}}
|-
| Little Joe 5
| The clamp holding the spacecraft was deflected by air pressure; due to this and incorrect wiring, the escape tower ignited too early and further failed to separate spacecraft from launch vehicle.{{sfn|Catchpole|2001|p=248}}{{refn|group=n| The clamp was subsequently tested by a rocket sled.{{sfn|Catchpole|2001|p=248}}}} Altitude: {{convert|10|mi|abbr=on}}{{sfn|Alexander & al.|1966|p=291}}
|-
| Mercury-Redstone 1
| Engine shutdown caused by improper separation of electrical cables;{{sfn|Alexander & al.|1966|p=298}} vehicle rose {{convert|4|in|cm|abbr=on}} and settled back on the pad.{{sfn|Alexander & al.|1966|p=294}}{{refn|group=n|Immediately after the Redstone's engine shut down, the capsule's [[Launch escape system|escape rocket]] jettisoned itself, leaving the capsule attached to the booster. The escape rocket rose to an altitude of {{convert|4000|ft|m|abbr=on}} and landed about {{convert|400|yd|m|abbr=on}} away. Three seconds after the escape rocket fired, the capsule deployed its [[drogue parachute]]; it then deployed the main and reserve parachutes.{{sfn|Alexander & al.|1966|p=294}}}}
|-
| Mercury-Redstone 1A
| First flight of Mercury / Redstone. Recovered by {{USS|Valley Forge|CV-45|6}}.{{sfn|Alexander & al.|1966|p=297}} Altitude: {{convert|130|mi|abbr=on}}{{sfn|Alexander & al.|1966|p=310}}
|-
| Mercury-Redstone 2
| Carried the chimpanzee Ham on suborbital flight. Recovered by {{USS|Donner|LSD-20|6}}{{sfn|Alexander & al.|1966|p=316}} {{convert|422|mi|abbr=on}} SE of Cape Canaveral; altitude: {{convert|157|mi|abbr=on}}{{sfn|Alexander & al.|1966|pp=638–639}}
|-
| Mercury-Atlas 2
| Recovered by USS ''Donner''{{sfn|Alexander & al.|1966|pp=321–322}} {{convert|1432|mi|abbr=on}} SE of Cape Canaveral.
|-
| Little Joe 5A
| Tower fired 14 seconds too soon; it failed to separate the spacecraft from the rocket.{{sfn|Alexander & al.|1966|p=327}}
|-
| Nowrap|Mercury-Redstone BD
| BD: Booster Development){{sfn|Alexander & al.|1966|p=330}}
|-
| Mercury-Atlas 3
| Upgraded from suborbital flight. Was aborted when the Atlas continued to vertically climb instead of tilting toward orbit; escaping capsule was recovered and reused in Mercury-Atlas 4.{{sfn|Alexander & al.|1966|p=337}}
|-
| Little Joe 5B
| Concluded Little Joe program.
|-style="background-color:#CDE;"
| Mercury-Atlas 4
| Completed one orbit and sent data to the ground; first orbital flight of the project.{{sfn|Alexander & al.|1966|p=386-387}} Recovery by {{USS|Decatur|DD-936|6}} {{convert|176|mi|abbr=on}} east of [[Bermuda]].{{sfn|Alexander & al.|1966|p=389}}
|-style="background-color:#CDE;"
| Mercury-Scout 1
| Was aborted after malfunction of booster's guidance system;{{sfn|Alexander & al.|1966|p=397}} results of Mercury-Atlas 4 and Mercury-Atlas 5 were used instead.{{sfn|Catchpole|2001|p=312}}
|-style="background-color:#CDE;"
| Mercury-Atlas 5
| Chimpanzee Enos completed a two-orbit flight, performing tasks to prove it possible for a person to function during a flight.{{sfn|Alexander & al.|1966|p=404}}{{refn|group=n|Was given a reward in the form a banana pellet or a punishment in the form of mild electrical shocks depending on whether or not he gave the right response to a given signal; by mistake he was sometimes given shocks on right answers.{{sfn|Alexander & al.|1966|p=405}}}} Last Mercury-Atlas test flight. Recovery by {{USS|Stormes|DD-780|6}}{{sfn|Alexander & al.|1966|p=406}} {{convert|255|mi|abbr=on}} SE of Bermuda.{{sfn|Grimwood|1963|p=169}}
|}
<gallery mode="packed">
Launch of Little Joe 1B, January 21, 1960.jpg|Little Joe 1B at launch with Miss Sam, 1960
Escape rocket of Mercury-Redstone 1-crop.jpg|Mercury-Redstone 1: launch escape system lift-off after 4<nowiki>''</nowiki> launch, 1960
Chimpanzee Ham in Biopack Couch for MR-2 flight MSFC-6100114.jpg|Mercury-Redstone 2: [[Ham (chimpanzee)|Ham]], 1961
Chimpanzee Enos before the flight of Mercury-Atlas 5 (cropped).jpg|Mercury-Atlas 5: [[Enos (chimpanzee)|Enos]], 1961
</gallery>
{{clear}}

===Canceled===
[[File:Jupiter_atlas_redstone_rockets_comparison.jpg|alt=Mercury-Jupiter (center) compared with Redstone (left) and Atlas (right).|thumb|Mercury-Jupiter (center) compared with Redstone (left) and Atlas (right).]]
Nine of the planned flights were canceled.

Mercury-Jupiter was a proposed suborbital launch configuration consisting of a [[PGM-19 Jupiter|Jupiter missile]] carrying a Mercury capsule. Two flights were planned in support of Project Mercury. The Mercury-Jupiter 1 flight would have been a heat shield test. The Mercury-Jupiter 2 flight was planned as a maximum dynamic pressure qualification test of the production Mercury spacecraft with a chimpanzee on board.<ref>{{cite web |title=Mercury-Jupiter MJ-2 |url=http://astronautix.com/flights/merr2mj2.htm |archive-url=https://web.archive.org/web/20111013154511/http://astronautix.com/flights/merr2mj2.htm |archive-date=2011-10-13 |website=Encyclopedia Astronautica}}</ref> On July 1, 1959, less than a year after the October, 1958 program start date, the flights were canceled due to budget constraints.<ref>{{cite web |last=Grimwood |first=James M. |title=Project Mercury – A Chronology – PART II (A) Research and Development Phase of Project Mercury |url=https://history.nasa.gov/SP-4001/p2a.htm |access-date=2024-03-01 |website=NASA |id=NASA SP-4001}}</ref>

Suborbital flights were planned for four other astronauts but the number of flights was cut down gradually and finally all remaining were canceled after Titov's flight.{{sfn|Alexander & al.|1966|p=377}}{{sfn|Catchpole|2001|p=474}}{{refn|group=n|Within the Mercury Project organization the suborbital flights were from the start criticized as being of little value and even compared to a circus act.{{sfn|Alexander & al.|1966|p=100}}}}

Mercury-Atlas 9 was intended to be followed by more one-day flights and even a three-day flight but with the coming of the Gemini Project it seemed unnecessary. The Jupiter booster was, as mentioned above, intended to be used for different purposes.

{| class="wikitable"
|-
! Mission
!Pilot
!  Planned Launch
!  Cancellation
|-
| Mercury-Jupiter 1
|
|
| July 1, 1959{{sfn|Grimwood|1963|p=81}}
|-
| Mercury-Jupiter 2
| Chimpanzee
| First quarter, 1960
| July 1, 1959{{sfn|Grimwood|1963|p=81}}{{refn|group=n|Proposed maximum dynamic pressure test for capsule.<ref name="MJ2" />}}
|-
| Mercury-Redstone 5
| Glenn (likely)
| March 1960{{sfn|Catchpole|2001|p=474}}
| August 1961{{sfn|Cassutt|Slayton|1994|p=104}}
|-
| Mercury-Redstone 6
|
| April 1960{{sfn|Catchpole|2001|p=474}}
| July 1961{{sfn|Cassutt|Slayton|1994|p=101}}
|-
| Mercury-Redstone 7
|
|May 1960{{sfn|Catchpole|2001|p=474}}
|
|-
|Mercury-Redstone 8
|
|June 1960{{sfn|Catchpole|2001|p=474}}
|
|-
| [[Mercury-Atlas 10]]
| Shepard
| October 1963
| June 13, 1963{{refn|group=n|Mercury-Atlas 10 was intended to be a three-day mission in November 1962 with extra supplies attached to the heat shield. Call-sign ''Freedom 7-II''. By January 1963, it was changed to a one-day back up mission for Mercury-Atlas 9. It was canceled after the success of the latter.{{sfn|Catchpole|2001|pp=385–386}}}}
|-
| Mercury-Atlas 11
| Grissom
| Fourth quarter, 1963
| October 1962<ref name="Mercury-Atlas 11"/>
|-
| Mercury-Atlas 12
| Schirra
| Fourth quarter, 1963
| October 1962<ref name="Mercury-Atlas 12"/>
|}

==Legacy==
[[File:Gordon cooper ticker tape.png|thumb|upright=0.85|[[Ticker tape parade]] for Gordon Cooper in New York City, May 1963]]

Today the Mercury program is commemorated as the first American human space program.{{sfn|Catchpole|2001|p=cover}} It did not win the race against the Soviet Union, but gave back national prestige and was scientifically a successful precursor of later programs such as Gemini, Apollo and Skylab.{{sfn|Catchpole|2001|p=417}}{{refn|International rules required that a pilot must land safely with the spacecraft; in reality, Gagarin landed separately by parachute; however, the Soviet Union did not admit this until 1971 when their claim was no longer in danger of being challenged.{{sfn|Siddiqi|2000|p=283}}|group=n}}

During the 1950s, some experts doubted that human spaceflight was possible.{{refn|In May 1957, five months before Sputnik I, the president of McDonnell, later the prime contractor, predicted that human spaceflight would not take place before 1990.{{sfn|Alexander & al.|1966|p=119}}|group=n}} Still, when [[John F. Kennedy]] was elected president, many, including him, had doubts about the project.{{sfn|Alexander & al.|1966|p=272}} As president he chose to support the programs a few months before the launch of ''Freedom 7'',{{sfn|Alexander & al.|1966|p=306}} which became a public success.{{sfn|Alexander & al.|1966|p=434}}{{refn|Along the roads in the US, drivers stopped to follow Freedom 7 on the radio. Later, 100 millions saw or listened to ''Friendship 7'', the first orbital flight, on TV or radio.{{sfn|Alexander & al.|1966|p=423}} The launch of ''Sigma 7'' and ''Faith 7'' were relayed live via [[communication satellite]] to television audiences in Western Europe.<ref name=Telstar/> Two of the three major US networks covered Sigma 7 minute-by-minute, while the third was showing the opening of the [[World Series]].{{sfn|Alexander & al.|1966|p=472}}|group=n}} Afterwards, a majority of the American public supported human spaceflight, and, within a few weeks, Kennedy announced a plan for a crewed mission to land on the Moon and return safely to Earth before the end of the 1960s.{{sfn|Alexander & al.|1966|p=363}}

The six astronauts who flew were awarded medals,{{sfn|Alexander & al.|1966|pp=362, 435, 459, 486, 502, 584}} driven in parades and two of them were invited to address a [[Joint session of the United States Congress|joint session of the US Congress]].{{sfn|Alexander & al.|1966|pp=435, 501}} Seeing as no women previously met the qualifications for the astronaut program, the question was raised as to whether or not they could. This led to the development of a project named [[Mercury 13]] by the media, in which thirteen American women successfully underwent the tests. The Mercury 13 program was not officially conducted by [[NASA]]. It was created by NASA physician [[William Randolph Lovelace II|William Randolph Lovelace]], who developed the physical and psychological tests used to select NASA's first seven male astronauts for Project Mercury. The women completed physical and psychological tests, but were never required to complete the training as the privately funded program was quickly cancelled. No female candidates adequately met the qualifications for the astronaut program [[NASA Astronaut Group 8|until 1978]], when a few finally qualified for the [[Space Shuttle program]].{{sfn|Catchpole|2001|p=448}}

Military Highway in [[Hampton, Virginia]] and [[Newport News, Virginia]] was renamed to [[Mercury Boulevard]].<ref>{{Cite web |date=2011-10-24 |title=What's in a name? {{!}} Mercury Boulevard |url=https://www.pilotonline.com/2011/10/24/whats-in-a-name-mercury-boulevard/ |access-date=2024-08-17 |website=The Virginian-Pilot |language=en-US}}</ref>

On February 25, 2011, the [[Institute of Electrical and Electronics Engineers]], the world's largest technical professional society, awarded [[Boeing]] (the successor company to McDonnell Aircraft) a Milestone Award for important inventions which debuted on the Mercury spacecraft.<ref name="BoeingMedia" />{{refn|Boeing received the award in recognition of Project Mercury's pioneering "navigation and control instruments, autopilot, rate stabilization and control, and [[fly-by-wire]] systems."<ref name="BoeingMedia"/>|group=n}}

===Depictions on film===
A short documentary, ''[[The John Glenn Story]]'', was released in 1962.

On film the program was portrayed in ''[[The Right Stuff (film)|The Right Stuff]]'', a 1983 adaptation of [[Tom Wolfe]]'s 1979 [[The Right Stuff (book)|book of the same name]],<ref name="IMdBRightStuff" /> in the 1998 HBO miniseries ''[[From the Earth to the Moon (miniseries)|From the Earth to the Moon]]'', in the 2016 film ''[[Hidden Figures]]'', and the 2020 Disney+ series ''[[The Right Stuff (TV series)|The Right Stuff]]'', which is also based on the Tom Wolfe book.

===Commemorations===
In 1964, a monument commemorating Project Mercury was unveiled near Launch Complex 14 at Cape Canaveral, featuring a metal logo combining the symbol of Mercury with the number 7.<ref name="Monument" />  This design was first issued to the Mercury astronauts in 1960 as a lapel pin.<ref name="pin">{{Cite web |last=Pearlman |first=Robert Z. |date=2020-01-06 |title='Pin'-nacle Achievement: The Story Behind NASA's Astronaut Pin |url=https://www.space.com/nasa-astronaut-pin-history.html |access-date=2022-08-22 |website=Space.com |language=en}}</ref>  In 1962, the [[United States Postal Service]] honored the Mercury-Atlas 6 flight with a Project Mercury commemorative stamp, the first US postal issue to depict a crewed spacecraft.<ref name="GlennStamp" />{{refn|The stamp first went on sale in Cape Canaveral, Florida on February 20, 1962, the same day as the first crewed orbital flight.<ref name="GlennStamp" /> On May 4, 2011, the Postal Service released a stamp commemorating the 50th anniversary of ''Freedom 7'', the first flight of the project with people onboard.<ref name="ShepardStamp" />|group=n}} 
<gallery mode="packed">
Project Mercury Pad14.jpg|Mercury monument at Launch Complex 14, 1964
Project_Mercury_4¢_US_Postage_stamp_February_20,_1962_FDC_Scott_-1193.jpg|Commemorative [[U.S. space exploration history on U.S. stamps#Project Mercury Issue of 1962|Project Mercury 4¢ US Postage stamp]]{{refn|group=n|The stamp was issued February 20, 1962, the day of John Glenn's flight in ''Friendship 7''. This one has a [[First day of issue]] postmark from Cape Canaveral post office.}}
</gallery>
{{Clear}}

===Displays===
The spacecraft that flew, together with some that did not, are on display in the United States. ''Friendship 7'' (Spacecraft No. 13) went on a global tour, popularly known as its "fourth orbit".{{sfn|Alexander & al.|1966|p=436}}

<gallery mode="packed">
File:20180320 Little Joe 5A Virginia Air and Space Center-1.jpg|''[[Little Joe 5B]]'' (Spacecraft No 14), [[Virginia Air and Space Science Center|Virginia Air and Space Center]]
File:20180328 Big Joe Mercury capsule Udvar-Hazy.jpg|[[Big Joe 1|''Big Joe'']] Boilerplate, [[Steven F. Udvar-Hazy Center]]
File:Mercury1A.JPG|[[Mercury-Redstone 1|''MR-1'']] & [[Mercury-Redstone 1A|''MR-1A'']] (Spacecraft No 2), [[John F. Kennedy Space Center|Kennedy Space Center]]
File:Mercury-Redstone 2 Capsule.jpg|''[[Mercury-Redstone 2]]'' (Spacecraft No. 5), [[California Science Center]]
File:Freedom 7 U.S. Naval Academy.JPG|''[[Mercury-Redstone 3|Freedom 7]] (Spacecraft No. 7)'' at the [[United States Naval Academy]], 2010
File:Liberty Bell 7 The Kansas Cosmosphere and Space Center.JPG|''[[Mercury-Redstone 4|Liberty Bell 7]]'' (Spacecraft No. 11) at the [[Kansas Cosmosphere and Space Center]], 2010
File:Friendship 7 the National Air and Space Museum.JPG|''[[Mercury-Atlas 6|Friendship 7]]'' (Spacecraft No. 13) at the [[National Air and Space Museum]], 2009
File:Aurora 7 the Museum of Science and Industry in Chicago.JPG|''[[Mercury-Atlas 7|Aurora 7]]'' (Spacecraft No. 18) at the [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], 2009
File:MA-8 Sigma 7 Astronaut Hall of Fame, Titusville, FL.JPG|''[[Mercury-Atlas 8|Sigma 7]]'' (Spacecraft No. 16) at the [[United States Astronaut Hall of Fame]], 2011
File:Faith 7 capsule in Space Center Houston.jpg|''[[Mercury-Atlas 9|Faith 7]]'' (Spacecraft No. 20) at [[Space Center Houston]], 2011
File:Mercury Spacecraft - Capsule 15B ‘Freedom 7 II’ (51281910923).jpg|Unflown Freedom 7 II (Spacecraft No. 15B) at [[Steven F. Udvar-Hazy Center]]
File:Mercury 10 at the Evergreen Aviation & Space Museum 1679 (6586666405).jpg|Unflown (Spacecraft No. 10), [[Evergreen Aviation & Space Museum]]
File:Mercury Procedures Simulator.JPG|Mercury Procedures Trainer at the [[U.S. Space & Rocket Center|U.S. Space and Rocket Center]], 2011
</gallery>

===Patches===
Commemorative patches were designed by entrepreneurs after the Mercury program to satisfy collectors.<ref name="patches" />{{refn|The only patches the Mercury astronauts wore were the NASA logo and a name tag.<ref name="patches"/> Each crewed Mercury spacecraft was painted black and decorated with a flight insignia, its call-sign, an American flag and the words United States.{{sfn|Catchpole|2001|p=132}}|group=n}}
<gallery mode="packed">
Mercury 3 - Patch.png
Mercury 4 - Patch.png
Mercury 6 - Patch.png
Aurora 7 patch.png
Mercury-8-patch.png
Mercury 9 - Patch.png
</gallery>

==Videos==
<gallery mode="packed">
MA-6.theora.ogv|John Glenn documentary from 50th Anniversary of ''Friendship 7'', 2012.
</gallery>

==Space program comparison==
<gallery mode="packed">
NASA spacecraft comparison.jpg|NASA illustration comparing boosters and spacecraft from [[Apollo program|Apollo]] (biggest), [[Project Gemini|Gemini]] and Mercury (smallest).
</gallery>

==See also==
* [[List of crewed spacecraft]]
* [[Julian Elvis Ward Jr.]]

== Notes ==
{{reflist|30em
| group = n
| colwidth =
| refs =
}}

==References==
{{reflist|20em|refs=
<ref name="Mercury-Atlas 11">{{cite web|title=Mercury MA-11|url=http://www.astronautix.com/flights/meryma11.htm|publisher=Encyclopedia Astronauticax|access-date=22 June 2013|url-status=dead|archive-url=https://web.archive.org/web/20130823192237/http://www.astronautix.com/flights/meryma11.htm|archive-date=August 23, 2013|df=mdy-all}}</ref>
<ref name="Mercury-Atlas 12">{{cite web|title=Mercury MA-12|url=http://www.astronautix.com/flights/meryma12.htm|publisher=Encyclopedia Astronautica|access-date=22 June 2013|url-status=dead|archive-url=https://web.archive.org/web/20130823200222/http://www.astronautix.com/flights/meryma12.htm|archive-date=August 23, 2013|df=mdy-all}}</ref>
<ref name=CocoaBeach>{{cite web|title=History-At-A-Glance|url=http://www.cityofcocoabeach.com/citylife/History_at_A_Glance.htm|publisher=City of Cocoa Beach|access-date=24 June 2013|url-status=dead|archive-url=https://web.archive.org/web/20130104190601/http://www.cityofcocoabeach.com/citylife/History_at_A_Glance.htm|archive-date=January 4, 2013|df=mdy-all}}</ref>
<ref name="MJ2">{{cite web |url=http://www.astronautix.com/flights/merr2mj2.htm |title=Mercury-Jupiter 2 (MJ-2) |publisher=Astronautix.com |access-date=2012-05-24 |url-status=dead |archive-url=https://web.archive.org/web/20120617195355/http://www.astronautix.com/flights/merr2mj2.htm |archive-date=June 17, 2012 |df=mdy-all }}</ref>
<ref name=Telstar>{{cite web|title=Mercury Atlas 8|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1962-052A|publisher=NASA|access-date=22 June 2013}}</ref>
<ref name="GlennStamp">{{cite web|title=Mystic stamp company|url=http://www.mysticstamp.com/viewProducts.asp?sku=1193|access-date=1 April 2012|archive-date=March 26, 2014|archive-url=https://web.archive.org/web/20140326102050/http://www.mysticstamp.com/viewProducts.asp?sku=1193|url-status=dead}}</ref>
<ref name="ShepardStamp">{{cite web|title=Stamps Mark Shepard's 1961 Flight|url=http://www.nasa.gov/topics/history/features/shepard_stamp.html|publisher=US Postal Service|access-date=5 May 2011|archive-date=April 6, 2012|archive-url=https://web.archive.org/web/20120406122605/http://www.nasa.gov/topics/history/features/shepard_stamp.html|url-status=dead}}</ref>
<ref name="BoeingMedia">{{cite web|title=Boeing Press Release|url=http://boeing.mediaroom.com/index.php?s=43&item=1639|access-date=25 February 2011}}</ref>
<ref name="IMdBRightStuff">{{cite web|publisher=IMdB|url=https://www.imdb.com/title/tt0086197/|title=The Right Stuff|access-date=2011-10-04}}</ref>
<ref name="lafleur20100308">{{cite news | url=http://www.thespacereview.com/article/1579/1 | title=Costs of US piloted programs | work=The Space Review | date=2010-03-08 | access-date=February 18, 2012 | author=Lafleur, Claude}}</ref>
<ref name=Glenn1998>{{cite web|url=http://www.abc.net.au/tv/canwehelp/txt/s2160601.htm|title=Moment in Time&nbsp;– Episode 1|author=Australian Broadcasting Corporation|website=[[Australian Broadcasting Corporation]] |author-link=Australian Broadcasting Corporation|date=February 15, 2008|access-date=June 25, 2013}}</ref>
<ref name="patches">{{cite web|last=Dorr|first=Eugene|title=History of Patches|url=http://genedorr.com/patches/History.html|access-date=20 June 2013}}</ref>
<ref name=Monument>{{cite web|title=Mercury Monument Dedication at Launch Complex 14|url=http://images.ksc.nasa.gov/photos/1964/captions/KSC-64C-5517.html|publisher=Kennedy Space Center|access-date=June 29, 2013|url-status=dead|archive-url=https://web.archive.org/web/20050117174129/http://images.ksc.nasa.gov/photos/1964/captions/KSC-64C-5517.html|archive-date=January 17, 2005|df=mdy-all}}</ref>
<ref name="NASAComp1">{{cite web|author1=NASA|author-link1=NASA|title=Computers in Spaceflight: The NASA Experience – Chapter One: The Gemini Digital Computer: First Machine in Orbit|url=https://history.nasa.gov/computers/ch1-1.html|website=NASA History|date=March 1988 |publisher=NASA|access-date=15 September 2016}}</ref>
<ref name="NASAComp8">{{cite web|author1=NASA|author-link1=NASA|title=Computers in Spaceflight: The NASA Experience – Chapter Eight: Computers in Mission Control|url=https://history.nasa.gov/computers/Ch8-2.html|website=NASA History|date=March 1988 |publisher=NASA|access-date=27 June 2021}}</ref>
<ref name="DanCompSpace">{{cite web|last1=Rutter|first1=Daniel|title=Computers in space|url=http://www.dansdata.com/spacecomp.htm|website=Dan's Data|access-date=15 September 2016|date=28 October 2004}}</ref>

}}

==Bibliography==
* {{cite book|title=This New Ocean: a History of Project Mercury|last1=Alexander|first1=C. C.|last2=Grimwood|first2=J. M.|last3=Swenson|first3=L. S.| date=1966| publisher=NASA| url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19670005605_1967005605.pdf|isbn=1934941875|location=US|ref={{sfnRef|Alexander & al.|1966}}}}
* {{cite book|title=Deke! U.S. Manned Space: From Mercury to the Shuttle|last1=Cassutt|first1=Michael|last2=Slayton|first2=Donald K. "Deke"|date=1994|edition=1st|publisher=[[Forge Books|Forge]] ([[St. Martin's Press]])|location=New York, US|isbn=0-312-85503-6|url=https://archive.org/details/dekeusmannedspac00slay}}
* {{cite book|last=Catchpole|first=John|title=Project Mercury - NASA's First Manned Space Programme|date=2001|publisher=Springer Praxis|location=Chichester, UK|isbn=1-85233-406-1|url-access=registration|url=https://archive.org/details/projectmercuryna0000catc}}
* {{cite book | last = Gatland | first = Kenneth | title = Manned Spacecraft | publisher = Macmillan | edition = Second | date = 1976 | location = New York | pages = 304 }}
* {{cite journal |last=Giblin |first=Kelly A. |date=Spring 1998 |title =Fire in the Cockpit! |journal=[[American Heritage of Invention & Technology]] |volume=13 |issue=4 |publisher=American Heritage Publishing |url=http://www.americanheritage.com/articles/magazine/it/1998/4/1998_4_46.shtml |archive-url=https://web.archive.org/web/20081120153024/http://www.americanheritage.com/articles/magazine/it/1998/4/1998_4_46.shtml |archive-date=November 20, 2008 |access-date=March 23, 2011}}
* {{cite book|title=Project Mercury. A Chronology – NASA SP-4001 |last=Grimwood|first=James M.| date=1963|url=https://history.nasa.gov/SP-4001/cover.htm| publisher=NASA|location=Washington DC, US|access-date=November 8, 2015}}
* {{Cite book|last=Hansen| first=James R. | title=[[First Man: The Life of Neil A. Armstrong]] | publisher=Simon & Schuster | date=2005 | isbn=0-7432-5631-X}}
* {{cite journal |last=Hollins |first=Hunter |date=11 Mar 2013 |title =Forgotten hardware: how to urinate in a spacesuit |journal=Advances in Physiology Education |volume=37 |issue= 1 |pages=123–128 |publisher=American Physilogy Society |doi=10.1152/advan.00175.2012 |pmid=23728129 |url=https://journals.physiology.org/doi/pdf/10.1152/advan.00175.2012|access-date=27 December 2023|url-access=subscription }}
* {{cite book|last=Kranz|first=Gene|title=Failure Is Not an Option: Mission Control from Mercury to Apollo 13 and Beyond|publisher=Berkley Books|location=New York|year=2000|isbn=0-425-17987-7}}
* {{Cite book | last=Nelson | first=Craig | title=Rocket Men: The Epic Story of the First Men on the Moon | location=New York, New York | publisher=Viking Penguin | year=2009 | isbn=978-0-670-02103-1 | url=https://archive.org/details/isbn_9780670021031 }}
*{{cite book|last=Shesol|first=Jeff|title=Mercury Rising: John Glenn, John Kennedy, and the New Battleground of the Cold War|publisher=W.W. Norton|location=New York|isbn=978-1-324-00324-3|year=2021}}
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* {{cite book|last=Unknown|title=Results of the second U.S. manned suborbital space flight| date=1961a| publisher=NASA| url=http://www.jsc.nasa.gov/history/mission_trans/MR04_TEC.PDF| location=US}}
* {{cite book|title=Results of the first United States manned orbital space flight, 20 February 1962|last=Unknown|url=http://science.ksc.nasa.gov/history/mercury/ma-6/docs/ma-6-results.pdf|date=1962|publisher=NASA|location=US|access-date=July 9, 2013|archive-date=November 2, 2021|archive-url=https://web.archive.org/web/20211102071604/https://science.ksc.nasa.gov/history/mercury/ma-6/docs/ma-6-results.pdf|url-status=dead}}
* {{cite book | last = Wilford | first = John Noble | author-link = John Noble Wilford | title = We Reach the Moon | url = https://archive.org/details/wereachmoonnewyo00wilf | url-access = registration | publisher = Bantam Books | date = July 1969 | location = New York, US }}
* {{cite web|author1=NASA|author-link1=NASA|title=Computers in Spaceflight: The NASA Experience – Chapter One: The Gemini Digital Computer: First Machine in Orbit|url=https://history.nasa.gov/computers/ch1-1.html|website=NASA History|date=March 1988 |publisher=NASA|access-date=15 September 2016}}
* {{cite web|last1=Rutter|first1=Daniel|title=Computers in space|url=http://www.dansdata.com/spacecomp.htm|website=Dan's Data|access-date=15 September 2016|date=28 October 2004}}
* {{cite web|title=Space flight chronology|url=http://www-03.ibm.com/ibm/history/exhibits/space/space_chronology.html|archive-url=https://web.archive.org/web/20050119055349/http://www-03.ibm.com/ibm/history/exhibits/space/space_chronology.html|url-status=dead|archive-date=January 19, 2005|website=IBM Archives|date=January 23, 2003 |publisher=IBM|access-date=15 September 2016}}

==External links==
{{Commons category|Mercury program}}
* [https://www.nasa.gov/mission_pages/mercury/index.html NASA Project Mercury images and videos] {{Webarchive|url=https://web.archive.org/web/20201128100852/http://www.nasa.gov/mission_pages/mercury/index.html |date=November 28, 2020 }}
* [https://history.nasa.gov/SP-4003/toc.htm Space Medicine In Project Mercury]
* [http://www.ibiblio.org/mscorbit/document.html PDFs of historical Mercury documents including familiarization manuals.]
* [http://www.hq.nasa.gov/office/pao/History/diagrams/mercury.html Project Mercury Drawings and Technical Diagrams] {{Webarchive|url=https://web.archive.org/web/20100712232928/http://www.hq.nasa.gov/office/pao/History/diagrams/mercury.html |date=July 12, 2010 }}
* {{Internet Archive film | gov.archives.arc.1151850 | The Astronauts: United States Project Mercury }}

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