View source for Titan IV

{{Short description|Expendable launch system used by the US Air Force}}
{{Infobox rocket
|image =Titan4B on Launch Complex 40.jpg
|caption = A Titan IV-B rocket carrying the ''[[Cassini-Huygens]]'' space research mission before takeoff from [[Launch Complex 40]] on [[Cape Canaveral Air Force Station|Cape Canaveral]], 12 October 1997 (NASA)
|name = Titan IV
|function = [[Heavy-lift launch vehicle]]
|manufacturer = [[Lockheed Martin]]
|country-origin = United States
|cpl = $432 million (USD)
|height = 50-62 m
|alt-height = 164-207 ft
|diameter = 3.05 m
|alt-diameter = 10 ft
|mass = 943,050 [[kilogram|kg]]
|alt-mass = 2,079,060 [[pound (mass)|lb]]
|stages = 3-5
|capacities =
    {{Infobox rocket/Payload
    |location=[[Low Earth orbit|LEO]]
    |kilos = 21,680 kg
    |pounds = 47,790 lb
    }}
    {{Infobox rocket/Payload
    |location=[[Polar orbit|Polar LEO]]
    |kilos = 17,600 kg
    |pounds = 38,800 lb
    }}
    {{Infobox rocket/Payload
    |location=[[Geosynchronous orbit|GSO]]
    |kilos = 5,760 kg
    |pounds = 12,690 lb
    }}
    {{Infobox rocket/Payload
    |location=[[Heliocentric orbit|HCO]]
    |kilos = 5,660 kg
    |pounds = 12,470 lb
    }}
|family = [[Titan (rocket family)|Titan]]
|comparable = [[Atlas V]], [[Delta IV Heavy]], [[Falcon 9]]
|status = Retired
|sites = [[Cape Canaveral Air Force Station Space Launch Complex 40|SLC-40]]/[[Cape Canaveral Air Force Station Space Launch Complex 41|41]], [[Cape Canaveral Air Force Station|Cape Canaveral]]<br />[[Vandenberg AFB Space Launch Complex 4|SLC-4E]], [[Vandenberg Air Force Base|Vandenberg AFB]]
|launches = 39<ref name=lm-ll>{{cite web |url=http://www.lockheedmartin.com/news/press_releases/2005/LOCKHEEDMARTINSLASTTITANIVSUCCESSFU.html |title=Lockheed Martin's Last Titan IV Successfully Delivers National Security Payload to Space |date=October 19, 2005 |url-status=dead |archive-url=https://web.archive.org/web/20080114010028/http://www.lockheedmartin.com/news/press_releases/2005/LOCKHEEDMARTINSLASTTITANIVSUCCESSFU.html |archive-date=January 14, 2008 }}</ref><br />('''IVA:''' 22, '''IVB:''' 17)
|success = 35<br />('''IVA:''' 20, '''IVB:''' 15)
|fail = 4 ('''IVA:''' 2, '''IVB:''' 2)
|first='''IV-A:''' 14 June 1989<br />'''IV-B:''' 23 February 1997
|last='''IV-A:''' 12 August 1998<br />'''IV-B:''' 19 October 2005
|payloads = [[Lacrosse (satellite)|Lacrosse]]<br />[[Defense Support Program|DSP]]<br />[[Milstar]]<br />[[Cassini-Huygens]]
|stagedata = <!--insert a stage template (below) for each stage-->
    {{Infobox rocket/Stage
    |type = booster
    |diff = IV-A
    |name = [[UA1207]]
    |number = 2
    |engines = United Technologies UA1207
    |thrust = 14.234 [[Newton (force)|MN]]
    |alt-thrust = 3,200,000 [[Pounds-force|lbf]]
    |SI = 272 seconds (2667 N·s/kg)
    |burntime = 120 seconds
    |fuel = [[Polybutadiene acrylonitrile|PBAN]]
    }}
    {{Infobox rocket/Stage
    |type = booster
    |diff = IV-B
    |name = [[Solid Rocket Motor Upgrade|SRMU]]
    |number = 2
    |engines = [[Hercules Inc.|Hercules]] USRM<ref>{{Cite web|url=http://www.astronautix.com/u/usrm.html|archive-url=https://web.archive.org/web/20161227214141/http://astronautix.com/u/usrm.html|url-status=dead|archive-date=December 27, 2016|title=USRM|website=www.astronautix.com}}</ref>
    |thrust = 15.12 MN
    |alt-thrust = 3,400,000 lbf
    |SI = 286 seconds (2805 N·s/kg)
    |burntime = 140 seconds
    |fuel = [[Hydroxyl-terminated polybutadiene|HTPB]]
    }}
    {{Infobox rocket/Stage
    |type = stage
    |stageno = First
    |engines = 2 [[LR87|LR87-AJ-11]]<ref>{{cite web |title=Analysis of Titan IV Launch Responsiveness |url=https://apps.dtic.mil/sti/tr/pdf/ADA259021.pdf |website=Analysis of Titan IV Launch Responsiveness (pg. 28) |access-date=February 26, 2024}}</ref>
    |thrust = 2,440 kN
    |alt-thrust = 548,000 lbf
    |SI = 302 seconds (2962 N·s/kg)
    |burntime = 164 seconds
    |fuel = [[Dinitrogen tetroxide|N<sub>2</sub>O<sub>4</sub>]] / [[Aerozine 50]]
    }}
    {{Infobox rocket/Stage
    |type = stage
    |stageno = Second
    |engines = 1 [[LR91|LR91-AJ-11]]
    |thrust = 467 kN
    |alt-thrust = 105,000 lbf
    |SI = 316 seconds (3100 N·s/kg)
    |burntime = 223 seconds
    |fuel = [[Dinitrogen tetroxide|N<sub>2</sub>O<sub>4</sub>]] / [[Aerozine 50]]
    }}
    {{Infobox rocket/Stage
    |type = stage
    |stageno = Third
    |diff = Optional
    |name = [[Centaur (rocket stage)|Centaur-T]]
    |engines = 2 [[RL10|RL10A-3-3A]]
    |thrust = 147 kN
    |alt-thrust =33,100 lbf
    |SI = 444 seconds (4354 N·s/kg)
    |burntime = 625 seconds
    |fuel = [[LH2|LH<sub>2</sub>]]/[[LOX]]
    }}
}}

'''Titan IV''' was a family of [[Heavy-lift launch vehicle|heavy-lift space launch vehicles]] developed by [[Martin Marietta]] and operated by the [[United States Air Force]] from 1989 to 2005.<ref>{{cite web
 |url=http://www.af.mil/shared/media/document/AFD-070618-036.pdf
 |title=Space and Missile System Center Mission and Organization
 |work=Space and Missile Systems Center's History Office
 |access-date=September 20, 2008
 |archive-date=September 11, 2008
 |archive-url=https://web.archive.org/web/20080911032526/http://www.af.mil/shared/media/document/AFD-070618-036.pdf
 |url-status=dead
 }}</ref> [[rocket launch|Launches]] were conducted from [[Cape Canaveral Air Force Station]], Florida<ref>{{Cite web|url=http://www.space.com/missionlaunches/launches/titan4_dsp_launch_010806.html|title=Titan 4B and Cape Canaveral|website=[[Space.com]]|access-date=2008-05-21|archive-date=2001-10-31|archive-url=https://web.archive.org/web/20011031182400/http://www.space.com/missionlaunches/launches/titan4_dsp_launch_010806.html|url-status=dead}}</ref> and [[Vandenberg Air Force Base]], California.<ref>{{Cite web|url=https://spaceflightnow.com/titan/b28/index.html|title=Spaceflight Now &#124; Titan Launch Report &#124; Titan 4 rocket expected to launch Lacrosse spy satellite|website=spaceflightnow.com}}</ref>

The Titan IV was the last of the [[Titan (rocket family)|Titan family of rockets]], originally developed by the [[Glenn L. Martin Company]] in 1958. It was retired in 2005 due to their high cost of operation and concerns over its toxic  [[hypergolic propellant]]s, and replaced with the [[Atlas V]] and [[Delta IV]] launch vehicles under the [[Evolved Expendable Launch Vehicle|EELV]] program. The final launch (B-30) from Cape Canaveral occurred on 29 April 2005, and the final launch from Vandenberg AFB occurred on 19 October 2005.<ref>{{Cite APOD|title=The Last Titan |date=27 October 2005 |access-date=2008-09-20}}</ref> [[Lockheed Martin Space Systems]] built the Titan IVs near Denver, Colorado, under contract to the [[Federal government of the United States|US government]].<ref name=lm-ll />

Two Titan IV vehicles are on display, at the [[National Museum of the United States Air Force]] in [[Dayton, Ohio]] and the [[Evergreen Aviation and Space Museum]] in [[McMinnville, Oregon]].

==Vehicle description==
The Titan IV was developed to provide assured capability to launch [[Space Shuttle]]–class payloads for the Air Force. The Titan IV could be launched with no [[Multistage rocket|third stage]], the [[Inertial Upper Stage]] (IUS), or the [[Centaur (rocket stage)|Centaur upper stage]].

The Titan IV was made up of two large [[solid-fuel rocket|solid-fuel rocket boosters]] and a two-stage liquid-fueled core. The two storable liquid fuel core stages used [[Aerozine 50]] fuel and [[nitrogen tetroxide]] oxidizer. These propellants are [[hypergolic]], igniting on contact, and are liquids at room temperature, so no tank insulation is needed. This allowed the launcher to be stored in a ready state for extended periods, but both propellants are extremely toxic.

The Titan IV could be launched from either coast: [[Cape Canaveral Air Force Station Space Launch Complex 40|SLC-40]] or [[Cape Canaveral Air Force Station Space Launch Complex 41|41]] at Cape Canaveral Air Force Station near Cocoa Beach, Florida and at [[Vandenberg AFB Space Launch Complex 4|SLC-4E]], at [[Vandenberg Air Force Base#Launch sites|Vandenberg Air Force Base launch sites]] 55 miles northwest of [[Santa Barbara, California|Santa Barbara]] California. Launches to [[polar orbit]]s occurred from Vandenberg, with most other launches taking place at Cape Canaveral.

===Titan IV-A===
Titan IV-A flew with steel-cased solid [[UA1207]] rocket motors (SRMs) produced by Chemical Systems Division.<ref name=perfImprovement>{{cite report|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720007149.pdf|title=A STUDY OF PERFORMANCE AND COST IMPROVEMENT POTENTIAL OF THE 120-IN.- (3.05 M) DIAMETER SOLID ROCKET MOTOR|publisher=United Aircraft Corporation|date=December 1971|access-date=26 February 2016|last1=Backlund|first1=S. J.|last2=Rossen|first2=J. N.}}</ref><ref name=shuttleBoosters>{{cite report|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720015135.pdf|title=Study of Solid Rocket Motors for a Space Shuttle Booster|publisher=United Technology Center|date=15 March 1972|access-date=26 February 2016}}</ref><ref>{{cite web|url=http://www.astronautix.com/engines/ua1207.htm|title=UA1207|publisher=Astronautix|access-date=26 February 2016|url-status=dead|archiveurl=https://web.archive.org/web/20160304000325/http://www.astronautix.com/engines/ua1207.htm|archivedate=4 March 2016}}</ref>

===Titan IV-B===
The Titan IV-B evolved from the Titan III family and was similar to the Titan 34D.

While the launcher family had an extremely good reliability record in its first two decades, this changed in the 1980s with the loss of a Titan 34D in 1985 followed by the disastrous explosion of another in 1986 due to a [[solid rocket motor|SRM]] failure.
Due to this, the Titan IV-B vehicle was intended to use the new composite-casing Upgraded Solid Rocket Motors.<ref>{{Cite web|url=http://www.astronautix.com/t/titan4b.html|archive-url=https://web.archive.org/web/20161227223146/http://astronautix.com/t/titan4b.html|url-status=dead|archive-date=December 27, 2016|title=Titan 4B|website=www.astronautix.com}}</ref> Due to development problems the first few Titan IV-B launches flew with the old-style UA1207 SRMs.

<gallery>
First TITAN IV launch from Complex 41 - 14 June 1989.jpg|Titan IV-A
Titan-4(01)A Centaur - ELINT-Payload.jpg|Titan-4(01)A Centaur 
Titan IVB Centaur launching ELINTspy satellite.jpg|Titan IV-B Centaur
LR91-AJ-11 rocket engine - Thrust chamber.jpg|[[LR91-AJ-11]] rocket engine thrust chamber and injector
Bottom of First Stage of Titan IVB Rocket - LR87 rocket engine nozzles.jpg|Bottom of first stage of Titan IV-B rocket
</gallery>

===General characteristics===
* Builder: Lockheed-Martin Astronautics
* Power Plant:
** Stage 0 consisted of two solid-rocket motors.
** Stage 1 used an [[Aerojet LR87#LR87-11/11A|LR87-AJ-11]] liquid-propellant rocket engine.
** Stage 2 used the [[LR91-AJ-11]] liquid-propellant engine.
** Optional upper stages included the [[Centaur (rocket stage)|Centaur]] and [[Inertial Upper Stage]].
* Guidance System: A [[Ring laser gyroscope|ring laser gyro]] guidance system manufactured by [[Honeywell]].
* Thrust:
** Stage 0: Solid rocket motors provided 1.7 million pounds force (7.56&nbsp;MN) per motor at liftoff.
** Stage 1: LR87-AJ-11 provided an average of 548,000 pounds force (2.44&nbsp;MN)
** Stage 2: LR91-AJ-11 provided an average of 105,000 pounds force (467&nbsp;kN).
** Optional Centaur ([[RL10|RL10A-3-3A]]) upper stage provided 33,100 pounds force (147&nbsp;kN) and the Inertial Upper Stage provided up to 41,500 pounds force (185&nbsp;kN).
* Length: Up to {{convert|204|ft|m}}
* Lift Capability:
** Could carry up to {{convert|47800|lb|kg}} into low Earth orbit
** up to {{convert|12700|lb|kg}} into a [[geosynchronous orbit]] when launched from Cape Canaveral AFS, Fla.;
** and up to {{convert|38800|lb|kg}} into a [[Low Earth orbit|low Earth]] [[polar orbit]] when launched from Vandenberg AFB.
** into geosynchronous orbit:
*** with Centaur upper stage {{convert|12700|lb|kg}}
*** with Inertial Upper Stage {{convert|5250|lb|kg}}
* [[Payload fairing]]:<ref>{{cite web |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a259021.pdf |archive-url=https://web.archive.org/web/20121009005330/http://www.dtic.mil/dtic/tr/fulltext/u2/a259021.pdf |url-status=live |archive-date=October 9, 2012 |title=Analysis of Titan IV launch responsiveness |author=Michael Timothy Dunn |publisher=Air Force Institute of Technology|date=Dec 1992 |access-date=2011-07-08}}</ref>
** Manufacturer: McDonnell Douglas Space Systems Co
** Diameter: {{convert|16.7|ft|m}}
** Length: 56, 66, 76, or 86&nbsp;ft
** Mass: 11,000, 12,000, 13,000, or 14,000&nbsp;lb
** Design: 3 sections, isogrid structure, Aluminum
* Maximum Takeoff Weight: Approximately 2.2 million pounds (1,000,000&nbsp;kg)
* Cost: Approximately $250–350 million, depending on launch configuration.
* Date deployed: June 1989
* Launch sites: Cape Canaveral AFS, Fla., and Vandenberg AFB, Calif.

===Upgrades===
====Solid Rocket Motor Upgrade test stand====
In 1988–89, The [[Parsons Corporation|Ralph M. Parsons Company]] designed and built a full-scale steel tower and deflector facility, which was used to test the Titan IV [[Solid Rocket Motor Upgrade]] (SRMU).<ref>{{Cite web|url=https://ceqanet.opr.ca.gov/1990040020/2|title=TITAN IV - SOLID ROCKET MOTOR UPGRADE PROGRAM AT VANDENBURG|first=Air Force, United|last=States|website=ceqanet.opr.ca.gov|date=26 February 1990 }}</ref>  The launch and the effect of the SRMU thrust force on the Titan IV vehicle were modeled.  To evaluate the magnitude of the thrust force, the SRMU was connected to the steel tower through load measurement systems and launched in-place.  It was the first full-scale test conducted to simulate the effects of the SRMU on the Titan IV vehicle.<ref>Chalhoub, Michel S., (1990) "Dynamic Analysis, Design, and Execution of a Full Scale SRMU Test Stand," Parsons Engineering Report No. 027-90</ref>

====Proposed aluminum-lithium tanks====
In the early 1980s, [[General Dynamics]] developed a plan to assemble a lunar landing spacecraft in-orbit under the name [[First Lunar Outpost|Early Lunar Access]]. A Space Shuttle would lift a lunar lander into orbit and then a Titan IV rocket would launch with a modified [[Shuttle-Centaur|Centaur G-Prime]] stage to rendezvous and dock. The plan required upgrading the Space Shuttle and Titan IV to use lighter [[aluminium-lithium alloy]] propellant tanks.<ref>{{Cite web|url=http://www.astronautix.com/e/earlylunaraccess.html|archive-url=https://web.archive.org/web/20160820151430/http://www.astronautix.com/e/earlylunaraccess.html|url-status=dead|archive-date=August 20, 2016|title=Early Lunar Access|website=www.astronautix.com}}</ref> The plan never came to fruition, but in the 1990s the Shuttle's [[External Tank]] was converted to aluminum-lithium tanks to rendezvous with the highly inclined orbit of the Russian [[Mir]] [[Space station|Space Station]].<ref>{{cite web|title=Super Lightweight External Tank|url=https://www.nasa.gov/sites/default/files/113020main_shuttle_lightweight.pdf|publisher=NASA.gov|access-date=November 3, 2022}}</ref>

== Type identification ==
The IV-A (40nA) used boosters with steel casings, the IV-B (40nB) used boosters with composite casings (the SRMU).

Type 401 used a Centaur 3rd stage, type 402 used an IUS 3rd stage. The other 3 types (without 3rd stages) were 403, 404, and 405:

* Type 403 featured no upper stage, for lower-mass payloads to higher orbits from Vandenberg.<ref name=At>{{Cite web|url=http://www.astronautix.com/t/index.html|archive-url=https://web.archive.org/web/20160710100524/http://www.astronautix.com/t/index.html|url-status=dead|archive-date=July 10, 2016|title=Encyclopedia Astronautica Index: T|website=www.astronautix.com}}</ref>
* Type 404 featured no upper stage, for heavier payloads to low orbits, from Vandenberg.<ref name=At/>
* Type 405 featured no upper stage, for lower-mass payloads to higher-orbit from Cape Canaveral.<ref name=At/>

==History==
[[File:Titan-IV.stl|alt=Interactive 3D model of the Titan IV|thumb|274x274px|Interactive 3D model of the Titan IV, fully assembled (left) and in exploded view (right)]]
The [[Titan (rocket family)|Titan rocket family]] was established in October 1955 when the Air Force awarded the [[Glenn L. Martin Company]] (later [[Martin-Marietta]], now part of [[Lockheed Martin]]) a contract to build an [[intercontinental ballistic missile]] ([[SM-68 Titan|SM-68]]). The resulting [[Titan I]] was the nation's first two-stage ICBM and complemented the [[SM-65 Atlas|Atlas ICBM]] as the second underground, vertically stored, silo-based ICBM. Both stages of the Titan I used [[liquid oxygen]] and [[RP-1]] as propellants.

A subsequent version of the Titan family, the [[LGM-25C Titan II|Titan II]], was a two-stage evolution of the Titan I, but was much more powerful and used different propellants. Designated as LGM-25C, the Titan II was the largest missile developed for the USAF at that time. The Titan II had newly developed engines which used Aerozine 50 and nitrogen tetroxide as fuel and oxidizer in a self-igniting, [[hypergolic propellant]] combination, allowing the Titan II to be stored underground ready to launch. Titan II was the first Titan vehicle to be used as a space launcher.

Development of the space launch only [[Titan III]] began in 1964, resulting in the Titan IIIA, eventually followed by the Titan IV-A and IV-B.

===CELV===
By the mid-1980s the United States government worried that the Space Shuttle, designed to launch all American payloads and replace all unmanned rockets, would not be reliable enough for military and classified missions. In 1984 [[Under Secretary of the Air Force]] and [[Director of the National Reconnaissance Office]] (NRO) [[Pete Aldridge]] decided to purchase '''Complementary Expendable Launch Vehicles''' (CELV) for ten NRO payloads; the name came from the government's expectation that the rockets would "complement" the shuttle. Later renamed Titan IV,<ref name="day20061120">Day, Dwayne A. "[http://www.thespacereview.com/article/748/1 The spooks and the turkey]" ''The Space Review'', 20 November 2006.</ref> the rocket would only carry three military payloads<ref name="eleazer20200706">{{Cite web |last=Eleazer |first=Wayne |date=2020-07-06 |title=National spaceports: the past |url=https://www.thespacereview.com/article/3982/1 |access-date=2020-07-07 |website=The Space Review}}</ref> paired with Centaur stages and fly exclusively from LC-41 at Cape Canaveral. However, the [[Challenger accident]] in 1986 caused a renewed dependence on [[expendable launch system]]s, with the Titan IV program significantly expanded. At the time of its introduction, the Titan IV was the largest and most capable [[expendable launch vehicle]] used by the USAF.<ref>{{cite web |url=http://www.au.af.mil/au/awc/systems/dvic468.htm
 |archive-url=https://web.archive.org/web/20000823221640/http://www.au.af.mil/au/awc/systems/dvic468.htm
 |url-status=dead
 |archive-date=August 23, 2000
 |title=Titan IV
 |publisher=USAF Air University |year=1996}}</ref>

The post-Challenger program added Titan IV versions with the [[Inertial Upper Stage]] (IUS) or no upper stages, increased the number of flights, and converted LC-40 at the Cape for Titan IV launches. As of 1991, almost forty total Titan IV launches were scheduled and a new, improved SRM ([[solid rocket motor]]) casing using lightweight composite materials was introduced.

===Program cost===
In 1990, the Titan IV Selected Acquisition Report estimated the total cost for the acquisition of 65 Titan IV vehicles over a period of 16 years to US$18.3 billion (inflation-adjusted US$ {{formatnum:{{Inflation|US|18.3|1990|r=1}}}} billion in {{inflation/year|US}}).<ref name="GAO NSIA-91-271">{{cite web|url=http://archive.gao.gov/d19t9/144770.pdf|title=TITAN IV LAUNCH VEHICLE --- Restructured Program Could Reduce Fiscal Year 1992 Funding Needs|date=September 1991|publisher=US General Accounting Office|first=Nancy R.|last=Kingsbury|access-date=2011-02-05|archive-date=2012-03-12|archive-url=https://web.archive.org/web/20120312081748/http://archive.gao.gov/d19t9/144770.pdf|url-status=dead}}</ref>

===Cassini–Huygens launch===
In October 1997, a Titan IV-B rocket launched ''[[Cassini–Huygens]]'', a pair of probes sent to [[Saturn]]. It was the only use of a Titan IV for a non-Department of Defense launch. ''Huygens'' landed on [[Titan (moon)|Titan]] on January 14, 2005. ''Cassini'' remained in orbit around Saturn. The Cassini Mission ended on September 15, 2017, when the spacecraft was sent into Saturn's atmosphere to burn up.

===Retirement===
While an improvement over the shuttle, the Titan IV was expensive and unreliable.{{r|day20061120}} By the 1990s, there were also growing safety concerns over its toxic propellants. The [[Evolved Expendable Launch Vehicle]] (EELV) program resulted in the development of the [[Atlas V]], [[Delta IV]], and [[Delta IV Heavy]] launch vehicles, which replaced Titan IV and a number of other legacy launch systems. The new EELVs eliminated the use of hypergolic propellants, reduced costs, and were much more versatile than the legacy vehicles.

===Surviving examples===
In 2014, the [[National Museum of the United States Air Force]] in [[Dayton, Ohio]], began a project to restore a Titan IV-B rocket. This effort was successful, with the display opening June 8, 2016.<ref>{{Cite web|url=https://www.nationalmuseum.af.mil/Upcoming/Press-Room/News/Article-Display/Article/792421/national-museum-of-the-us-air-force-fourth-building-now-open/|title=National Museum of the U.S. Air Force fourth building now open|website=National Museum of the United States Air Force™|date=7 June 2016 }}</ref> The only other surviving Titan IV components are at the [[Wings Over the Rockies Air and Space Museum]] in Denver, Colorado which has two Titan Stage 1 engines, one Titan Stage 2 engine, and the interstage ‘skirt’ on outdoor display;<ref>{{cite web |title=Titan Missile Program |url=https://wingsmuseum.org/portfolio/titan-missile-program/ |publisher=Wings over the Rockies Museum}}</ref> and at the [[Evergreen Aviation and Space Museum]] in McMinnville, Oregon, including the core stages and parts of the solid rocket motor assembly.<ref>{{Cite web|url=https://www.spacearchive.info/news-2006-09-26-laafb.htm|title=Titan IV Solid Rocket Motors Destroyed|website=www.spacearchive.info}}</ref><gallery mode="packed">
File:U.S. Air Force Museum C (26).jpg|Titan IV-B in the [[National Museum of the United States Air Force]]
File:U.S. Air Force Museum (53).jpg|Titan IV-B in the National Museum of the United States Air Force
File:2014 08 140829-F-IO108-012.jpg|Titan IV-B in the restoration hangar at the National Museum of the United States Air Force. This is Stage One aft with two Aerojet LR87-AJ-11 engines.
File:160323-F-IO108-008.jpg|Titan IV-B stage one and SRMU's at the National Museum of the United States Air Force
File:Titan IVB at the Evergreen Aviation & Space Museum 1589 (6586633721).jpg|Titan IV-B at the [[Evergreen Aviation and Space Museum]]
File:Titan IVB at the Evergreen Aviation & Space Museum 1591 (6586634435).jpg|Titan IV-B at the Evergreen Aviation and Space Museum
File:Titan IVB at the Evergreen Aviation & Space Museum 1599 (6586636607).jpg|Titan IV-B at the Evergreen Aviation and Space Museum
</gallery>

==Launch history==
{{Main|List of Titan launches}}
{{sticky-header}}
{| class="wikitable collapsible sticky-header"
|-
! Date / <br /> Time (UTC)
! Launch Site
! S/N
! Type
! Payload
! Outcome
! width=25% | Remarks
|-
| 14 June 1989 <br /> 13:18
| [[Cape Canaveral Air Force Station|CCAFS]] [[Cape Canaveral Air Force Station Space Launch Complex 41|LC-41]]
| K-1
| 402A / [[Inertial Upper Stage|IUS]]
| USA-39 ([[Defense Support Program|DSP]]-14)
| {{Success}}
| An engine bell burn-through left only a narrow margin for success.
|-
| 8 June 1990 <br /> 05:21
| CCAFS LC-41
| K-4
| 405A
| USA-60 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-61 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-62 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-59 Satellite Launch Dispenser Communications (SLDCOM)
| {{Success}}
|
|-
| 13 November 1990 <br /> 00:37
| CCAFS LC-41
| K-6
| 402A / [[Inertial Upper Stage|IUS]]
| USA-65 ([[Defense Support Program|DSP]]-15)
| {{Success}}
|
|-
| 8 March 1991 <br /> 12:03
| [[Vandenberg AFB|VAFB]] [[Vandenberg AFB Space Launch Complex 4|LC-4E]]
| K-5
| 403A
| USA-69 ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
|
|-
| 8 November 1991 <br /> 07:07
| VAFB LC-4E
| K-8
| 403A
| USA-74 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-76 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-77 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-72 SLDCOM
| {{Success}}
|
|-
| 28 November 1992 <br /> 21:34
| VAFB LC-4E
| K-3
| 404A
| USA-86 ([[KH-11 Kennen|KH-11]])
| {{Success}}
|
|-
| 2 August 1993 <br /> 19:59
| VAFB LC-4E
| K-11
| 403A
| [[Naval Ocean Surveillance System|NOSS]] x3 <br />SLDCOM
| {{Failure}}
| SRM exploded at T+101s due to damage caused during maintenance on ground.
|-
| 7 February 1994 <br /> 21:47
| CCAFS [[Cape Canaveral Air Force Station Space Launch Complex 40|LC-40]]
| K-10
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-99 ([[Milstar]]-1)
| {{Success}}
|
|-
| 3 May 1994 <br /> 15:55
| CCAFS LC-41
| K-7
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-103 ([[Trumpet (satellite)|Trumpet]])
| {{Success}}
|
|-
| 27 August 1994 <br /> 08:58
| CCAFS LC-41
| K-9
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-105 ([[Mercury (satellite)|Mercury]])
| {{Success}}
|
|-
| 22 December 1994 <br /> 22:19
| CCAFS LC-40
| K-14
| 402A / [[Inertial Upper Stage|IUS]]
| USA-107 ([[Defense Support Program|DSP]]-17)
| {{Success}}
|
|-
| 14 May 1995 <br /> 13:45
| CCAFS LC-40
| K-23
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-110 ([[Orion (satellite)|Orion]])
| {{Success}}
|
|-
| 10 July 1995 <br /> 12:38
| CCAFS LC-41
| K-19
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-112 ([[Trumpet (satellite)|Trumpet]])
| {{Success}}
|
|-
| 6 November 1995 <br /> 05:15
| CCAFS LC-40
| K-21
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-115 ([[Milstar]]-2)
| {{Success}}
|
|-
| 5 December 1995 <br /> 21:18
| VAFB LC-4E
| K-15
| 404A
| USA-116 ([[KH-11 Kennen|KH-11]])
| {{Success}}
|
|-
| 24 April 1996 <br /> 23:37
| CCAFS LC-41
| K-16
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-118 ([[Mercury (satellite)|Mercury]])
| {{Success}}
|
|-
| 12 May 1996 <br /> 21:32
| VAFB LC-4E
| K-22
| 403A
| USA-120 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-121 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-122 ([[Naval Ocean Surveillance System|NOSS]])<br />USA-119 (SLDCOM)<br />USA-123 Tethers in Space Physics Satellite (TiPS)<br />USA-124 (TiPS)
| {{Success}}
|
|-
| 3 July 1996 <br /> 00:30
| CCAFS LC-40
| K-2
| 405A
| USA-125 ([[Satellite Data System|SDS]])
| {{Success}}
|
|-
| 20 December 1996 <br /> 18:04
| VAFB LC-4E
| K-13
| 404A
| USA-129 ([[KH-11 Kennen|KH-11]])
| {{Success}}
| [[List of NRO Launches|NROL-2]]
|-
| 23 February 1997 <br /> 20:20
| CCAFS LC-40
| B-24
| 402B / [[Inertial Upper Stage|IUS]]
| USA-130 ([[Defense Support Program|DSP]]-18)
| {{Success}}
|
|-
| 15 October 1997 <br /> 08:43
| CCAFS LC-40
| B-33
| 401B / [[Centaur (rocket stage)|Centaur]]
| [[Cassini–Huygens|Cassini]]<br />[[Huygens (spacecraft)|Huygens]]
| {{Success}}
|
|-
| 24 October 1997 <br /> 02:32
| VAFB LC-4E
| A-18
| 403A
| USA-133 ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
| [[List of NRO Launches|NROL-3]]
|-
| 8 November 1997 <br /> 02:05
| CCAFS LC-41
| A-17
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-136 ([[Trumpet (satellite)|Trumpet]])
| {{Success}}
| [[List of NRO Launches|NROL-4]]
|-
| 9 May 1998 <br /> 01:38
| CCAFS LC-40
| B-25
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-139 ([[Orion (satellite)|Orion]])
| {{Success}}
| [[List of NRO Launches|NROL-6]]
|-
| 12 August 1998 <br /> 11:30
| CCAFS LC-41
| A-20
| 401A / [[Centaur (rocket stage)|Centaur]]
| [[List of NRO Launches|NROL-7]] ([[Mercury (satellite)|Mercury]])
| {{Failure}}
| Guidance system short-circuited at T+40s due to frayed wire, vehicle lost control and destroyed by range safety.
|-
| 9 April 1999 <br /> 17:01
| CCAFS LC-41
| B-27
| 402B / [[Inertial Upper Stage|IUS]]
| USA-142 ([[Defense Support Program|DSP]]-19)
| {{Failure}}
| Spacecraft failed to separate from IUS stage.
|-
| 30 April 1999 <br /> 16:30
| CCAFS LC-40
| B-32
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-143 ([[Milstar]]-3)
| {{Failure}}
| Centaur software database error caused loss of [[Spacecraft attitude control|attitude control]], insertion burns done incorrectly. Satellite deployed into useless orbit.
|-
| 22 May 1999 <br /> 09:36
| VAFB LC-4E
| B-12
| 404B
| USA-144 ([[Misty (satellite)|Misty]])
| {{Success}}
| [[List of NRO Launches|NROL-8]]
|-
| 8 May 2000 <br /> 16:01
| CCAFS LC-40
| B-29
| 402B / [[Inertial Upper Stage|IUS]]
| USA-149 ([[Defense Support Program|DSP]]-20)
| {{Success}}
|
|-
| 17 August 2000 <br /> 23:45
| VAFB LC-4E
| B-28
| 403B
| USA-152 ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
| [[List of NRO Launches|NROL-11]]
|-
| 27 February 2001 <br /> 21:20
| CCAFS LC-40
| B-41
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-157 ([[Milstar]]-4)
| {{Success}}
|
|-
| 6 August 2001 <br /> 07:28
| CCAFS LC-40
| B-31
| 402B / [[Inertial Upper Stage|IUS]]
| USA-159 ([[Defense Support Program|DSP]]-21)
| {{Success}}
|
|-
| 5 October 2001 <br /> 21:21
| VAFB LC-4E
| B-34
| 404B
| USA-161 ([[KH-11 Kennen|KH-11]])
| {{Success}}
| [[List of NRO Launches|NROL-14]]
|-
| 16 January 2002 <br /> 00:30
| CCAFS LC-40
| B-38
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-164 ([[Milstar]]-5)
| {{Success}}
|
|-
| 8 April 2003 <br /> 13:43
| CCAFS LC-40
| B-35
| 401B / [[Centaur (rocket stage)|Centaur]]
| [[USA-169]] ([[Milstar]]-6)
| {{Success}}
|
|-
| 9 September 2003 <br /> 04:29
| CCAFS LC-40
| B-36
| 401B / [[Centaur (rocket stage)|Centaur]]
| [[USA-171]] ([[Orion (satellite)|Orion-5]])
| {{Success}}
| [[List of NRO Launches|NROL-19]]
|-
| 14 February 2004 <br /> 18:50
| CCAFS LC-40
| B-39
| 402B / [[Inertial Upper Stage|IUS]]
| [[USA-176]] ([[Defense Support Program|DSP]]-22)
| {{Success}}
|
|-
| 30 April 2005 <br /> 00:50
| CCAFS LC-40
| B-30
| 405B
| [[USA-182]] ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
| [[List of NRO Launches|NROL-16]]
|-
| 19 October 2005 <br /> 18:05
| VAFB LC-4E
| B-26
| 404B
| [[USA-186]] ([[KH-11 Kennen|KH-11]])
| {{Success}}
| [[List of NRO Launches|NROL-20]]
|}

==Launch failures==
The Titan IV experienced four catastrophic launch failures.

===1993 booster explosion===
[[File:Titan IVA K-11 failure (August 1993).jpg|thumb|upright|Titan IVA K-11 moments before the August 1993 failure]]
On August 2, 1993, Titan IV K-11 lifted from SLC-4E carrying a NOSS SIGNIT satellite. Unusually for DoD launches, the Air Force invited civilian press to cover the launch, which became more of a story than intended when the booster exploded 101 seconds after liftoff. Investigation found that one of the two SRMs had burned through, resulting in the destruction of the vehicle in a similar manner as the earlier 34D-9 failure. An investigation found that an improper repair job was the cause of the accident.<ref>{{Cite web|url=http://www.astronautix.com/t/titan403a.html|archive-url=https://web.archive.org/web/20161228002517/http://astronautix.com/t/titan403a.html|url-status=dead|archive-date=December 28, 2016|title=Titan 403A|website=www.astronautix.com}}</ref>

After Titan 34D-9, extensive measures had been put in place to ensure proper SRM operating condition, including X-raying the motor segments during prelaunch checks. The SRMs that went onto K-11 had originally been shipped to Cape Canaveral, where X-rays revealed anomalies in the solid propellant mixture in one segment. The defective area was removed by a pie-shaped cut in the propellant block. However, most of CSD's qualified personnel had left the program by this point and so the repair crew in question did not know the proper procedure. After replacement, they neglected to seal the area where the cut in the propellant block had been made. Post repair X-rays were enough for CC personnel to disqualify the SRMs from flight, but the SRMs were then shipped to Vandenberg and approved anyway. The result was a near-repeat of 34D-9; a gap was left between the propellant and SRM casing and another burn-through occurred during launch.

===1998 IV-A electrical failure===
1998 saw the failure of Titan K-17 with a Navy [[ELINT]] [[Mercury (satellite)]] from Cape Canaveral around 40 seconds into the flight. K-17 was several years old and the last Titan IV-A to be launched. The post-accident investigation showed that the booster had dozens of damaged or chafed wires and should never have been launched in that operating condition, but the Air Force had put extreme pressure on launch crews to meet program deadlines. The Titan's fuselage was filled with numerous sharp metal protrusions that made it nearly impossible to install, adjust, or remove wiring without it getting damaged. Quality control at Lockheed's Denver plant, where Titan vehicles were assembled, was described as "awful".

The proximal cause of the failure was an electrical short that caused a momentary power dropout to the guidance computer at T+39 seconds. After power was restored, the computer sent a spurious pitch down and yaw to the right command. At T+40 seconds, the Titan was traveling at near supersonic speed and could not handle this action without suffering a structural failure. The sudden pitch downward and resulting aerodynamic stress caused one of the SRMs to separate. The ISDS (Inadvertent Separation Destruct System) automatically triggered, rupturing the SRM and taking the rest of the launch vehicle with it. At T+45 seconds, the Range Safety Officer sent the destruct command to ensure any remaining large pieces of the booster were broken up.<ref>{{Cite web|url=http://www.astronautix.com/lvs/titr401a.htm|title=Titan Centaur 401A|website=www.astronautix.com|archive-url=https://web.archive.org/web/20160303214535/http://www.astronautix.com/lvs/titr401a.htm|archive-date=3 March 2016|url-status=dead}}{{cbignore|bot=medic}}</ref>

An extensive recovery effort was launched, both to diagnose the cause of the accident and recover debris from the classified satellite. All of the debris from the Titan had impacted offshore, between three and five miles downrange, and at least 30% of the booster was recovered from the sea floor. Debris continued to wash ashore for days afterward, and the salvage operation continued until October 15.

The Air Force had pushed for a "launch on demand" program for DOD payloads, something that was almost impossible to pull off especially given the lengthy preparation and processing time needed for a Titan IV launch (at least 60 days). Shortly before retiring in 1994, General [[Chuck Horner]] referred to the Titan program as "a nightmare". The 1998-99 schedule had called for four launches in less than 12 months. The first of these was Titan K-25 which successfully orbited an Orion SIGNIT satellite on May 9, 1998. The second was the K-17 failure, and the third was the K-32 failure.

===Stage failure to separate===
After a delay caused by the investigation of the previous failure, the 9 April 1999 launch of K-32 carried a DSP [[early warning satellite]]. The IUS second stage failed to separate, leaving the payload in a useless orbit. Investigation into this failure found that wiring harnesses in the IUS had been wrapped too tightly with electrical tape so that a plug failed to disconnect properly and prevented the two IUS stages from separating.

===Centaur database error===
The fourth launch was K-26 on April 30, 1999, carrying a [[Milstar]] communications satellite. During the Centaur coast phase flight, the [[roll control]] thrusters fired open-loop until the RCS fuel was depleted, causing the upper stage and payload to rotate rapidly. On restart, the Centaur cartwheeled out of control and left its payload in a useless orbit. This failure was found to be the result of an incorrectly entered database parameter in the guidance computer. The error caused the roll rate gyro data to be ignored by the flight computer.<ref name="mit-software-accidents">{{cite web |last1=Leveson |first1=Nancy G., Ph.D. |title=The Role of Software in Recent Aerospace Accidents |url=http://sunnyday.mit.edu/accidents/issc01.pdf |website=sunnyday.mit.edu |publisher=19th International System Safety Conference |access-date=19 April 2020 |date=September 10–14, 2001 }}</ref><ref>{{citation |last=Eleazer |first=Wayne |title= Launch failures: the predictables |url=https://www.thespacereview.com/article/2884/1 |website= thespacereview.com |date=December 14, 2015 }}</ref>

==See also==
* [[Comparison of heavy lift launch systems]]
* [[List of Titan launches]], Titan I, II, III & IV

== References ==
{{Reflist}}

==External links==
{{Commons category|Titan IV}}
* [http://www.au.af.mil/au/awc/space/factsheets/titan_ivb.htm USAF Titan IVB Fact Sheet] {{Webarchive|url=https://web.archive.org/web/20180430145108/http://www.au.af.mil/au/awc/space/factsheets/titan_ivb.htm |date=2018-04-30 }}
* [https://web.archive.org/web/20080503143356/http://www.pr.afrl.af.mil/archive/video.html Titan IV Ignition Videos]
* [https://web.archive.org/web/20060929003140/http://saturn.jpl.nasa.gov/multimedia/videos/launch/index.cfm Cassini Huygens Aboard a Titan IV-B Launch Videos]
* [https://web.archive.org/web/20051116074244/http://astronautix.com/craft/earccess.htm Early Lunar Access]

{{Titan rockets}}
{{USAF space vehicles}}
{{Expendable launch systems}}
{{US launch systems}}

[[Category:Lockheed Martin]]
[[Category:2005 in spaceflight]]
[[Category:Titan (rocket family)]]