View source for Vandenberg Space Launch Complex 6

{{short description|Launch pad}}
{{Use dmy dates|date=July 2024}}
{{Infobox launch pad
|name = Space Launch Complex 6
|image = Delta IV launch 2013-08-28.jpg
|caption = [[Delta IV Heavy]] lifts off from SLC-6 in August&nbsp;2013
|site = [[Vandenberg Space Force Base]]
|location = {{coord|34.5813|N|120.6266|W|display=inline,title|format=dms}}
| utc_offset      = −08:00
| time_zone       = [[Pacific Standard Time|PST]]
| utc_offset_DST  = −07:00
| time_zone_DST   = [[Pacific Daylight Time|PDT]]
| operator        = [[United States Space Force]] (owner)<br/>[[SpaceX]] (tenant)
|short = SLC-6
|pads = 1
|inclination = 55–145°<ref>{{Cite web |date=September 2021 |title=Falcon User's Guide |url=https://www.spacex.com/media/falcon-users-guide-2021-09.pdf |website=[[SpaceX]] |page=11}}</ref>
| paddetails  = {{Infobox launch pad/pad
 | status      = Inactive, pending modifications for SpaceX
 | launches    = 19
 | first       = 15 August 1995  |first_details = [[Athena I]] ([[GemStar-1]])
 | last        = 24 September 2022 |last_details  = [[Delta IV Heavy]] ([[List of NRO launches|NROL-91]])
 | rockets     = {{plainlist|
* '''Future''': [[Falcon 9]], [[Falcon Heavy]]
* '''Retired''': [[Athena I]], [[Athena II]], [[Delta IV]], [[Delta IV Heavy]]
* '''Plans cancelled''': [[Titan IIIC]], [[Titan IIIM]], [[Space Shuttle]], [[Titan IV]], [[OmegA]]<ref name=berger20200820>[https://twitter.com/SciGuySpace/status/1296462155559186436 https://twitter.com/SciGuySpace/status/1296462155559186436] {{Webarchive|url=https://web.archive.org/web/20200820150733/https://twitter.com/SciGuySpace/status/1296462155559186436 |date=20 August 2020 }}, Ars Technica Senior Space Editor Eric Berger, 20 August 2020.</ref>
}}
  }}
}}

'''Vandenberg Space Launch Complex 6''' ('''SLC-6''', pronounced "Slick Six") is a [[launch pad]] and associated support infrastructure at [[Vandenberg Space Force Base]] in [[California]]. Construction at the site began in 1966, but the first launch didn't occur until 1995 due to program cancellations and subsequent repurposing efforts.

The site was originally envisioned to support [[Titan IIIM]] rockets and the [[Manned Orbiting Laboratory]]. However, these projects were terminated before SLC-6's completion. Between 1979 and 1986 the facilities received extensive modifications to accommodate the [[Space Shuttle]]. However, budgetary constraints, safety considerations, and political factors ultimately led to the cancellation of Shuttle operations from the West Coast.

SLC-6 facilitated four launches of [[Athena (rocket family)|Athena]] rockets between 1995 and 1999 with minimal modifications. Subsequently, it underwent modifications to support the [[Delta IV]] and [[Delta IV Heavy]], which conducted ten successful missions between 2006 and 2022. In 2023, SpaceX secured a lease agreement for SLC-6, with plans to modify the facility for [[Falcon 9]] and [[Falcon Heavy]] launches commencing in 2025.

Vandenberg's southward launch trajectory is advantageous for deploying satellites into high-inclination polar and Sun-synchronous orbits, needed for weather forecasting, Earth observation, and reconnaissance missions as they enable comprehensive and regular global coverage. Launching into such orbits from the East Coast of the United States presents significant challenges due to geographical constraints.<ref>{{cite web|title=Launch Sites|url=http://spaceflight.nasa.gov/shuttle/reference/shutref/sts/launch.html|archive-url=https://web.archive.org/web/19991013033531/http://spaceflight.nasa.gov/shuttle/reference/shutref/sts/launch.html|url-status=dead|archive-date=13 October 1999|publisher=NASA Human Spaceflight Office}}</ref>

==History==

SLC-6, part of Vandenberg's "South Base," was originally part of the Sudden Ranch, prior to its purchase by the [[U.S. Air Force]] in the mid-1960s under the law of [[eminent domain]]. In addition to the ranch, the [[Point Arguello Light]] was based there, which in 1967 was replaced by an automated light. There was also the Point Arguello [[LORAN]] station, de-established 31 December 1979.<ref>{{cite web | url=https://www.loran-history.info/stations/point_arguello/point_arguello.htm | title=Loran Station Point Arguello }}</ref>
===Titan (1966–1969)===
No [[Titan III|Titans]] were launched from SLC-6. After purchase of south base, the Air Force started construction of the SLC-6 facility on 12 March 1966, to support launches of a [[Titan IIIM]] for the [[Manned Orbiting Laboratory]] (MOL). After significant construction work was completed, the MOL program was cancelled on 10 June 1969, so further work on SLC-6 stopped as the facility was placed in [[Mothball#In_popular_culture|mothball]] status.<ref>{{cite news|last=David|first=Leonard|title=Declassified: US Military's Secret Cold War Space Project Revealed
|url=https://www.space.com/31470-manned-orbiting-laboratory-military-space-station.html|date=30 December 2015|access-date=26 September 2022|work=space.com}}</ref>

===Space Shuttle (1972–1989)===
[[File:Space Shuttle Discovery and SCA over Vandenberg AFB SLC-6 - DF-SC-85-09923.jpg|thumb|{{OV|103}} atop [[Shuttle Carrier Aircraft]] 905, flies over SLC-6 in November 1984, for testing of infrastructure at the base]]

No Space shuttles were launched from SLC-6. With plans of launching civilian and military equatorial space shuttle flights from [[Kennedy Space Center]] (KSC) and military polar orbit flights from Vandenberg, [[NASA]] and the Air Force looked at different sites for launching the shuttle, finally deciding upon SLC-6, due to its dedicated crewed spaceflight role that was left over from the canceled MOL/Titan program.<ref>{{cite web|last=Heppenheimer|first=T.A.|title=The Space Shuttle Decision: Chapter 9: Nixon’s Decision|url=https://space.nss.org/the-space-shuttle-decision-chapter-9/|access-date=26 September 2022|work=National Space Society}}</ref><ref name=vslc6>{{cite web|title=Space Launch Complex 6 (SLC-6)|url=https://www.globalsecurity.org/space/facility/vafb-slc-6.htm|access-date=26 September 2022|work=GlobalSecurity.org}}</ref>

In 1972, Vandenberg AFB was chosen as the western launch site for Air Force shuttle launches. Use of SLC-6 was approved in 1975, and re-construction of the former MOL launch facility occurred between January 1979 and July 1986 as SLC-6 was rebuilt to accommodate the space shuttle.<ref name=STSaldridge/>

There were several reasons for using SLC-6:<ref name=vslc6/>
*Florida shuttle launches to polar orbit would have entailed a large payload penalty;
*Florida shuttle launches to polar orbit would necessitate overflying [[South Carolina]], and the discarded [[Space Shuttle external tank|external tank]] would overfly [[Canada]] and [[Russia]].
*Use of the existing and partially constructed [[Titan III]] facilities at SLC-6 would reduce building costs for the shuttle launch complex.

A Senate report summarized: "The Air Force originally justified the expenditure of such SLC-6 funding on the basis of a need to launch high-priority military payloads into polar orbits. After Defense Department officials testified that polar orbits could not be achieved by launching from Kennedy Space Center in Florida, the Congress initiated construction of ... SLC-6."<ref name=vslc6/>

[[File:Vandenberg AFB Shuttle Launch Site.PNG|thumb|SLC-6 site layout in shuttle launch configuration]]

There were significant layout differences between the shuttle launch complexes at KSC and SLC-6 at Vandenberg, with the facilities at KSC closer together, but with stacking operations taking place right at the launch pad at SLC-6

At KSC, the Shuttle arrived at the [[Shuttle Landing Facility]] airport either by gliding in from space or piggybacking on the [[Shuttle Carrier Aircraft]] and then being unloaded using the [[Mate-Demate Device]]. From there, it was towed a short distance to one of three [[Orbiter Processing Facility]] hangars where it was refurbished. When the orbiter was ready, it was towed across the road to the [[Vehicle Assembly Building]] where it was stacked atop a [[mobile launcher platform]]. From there, the vehicle was taken to one of two pads at [[Launch Complex 39]] about a mile away by a [[crawler-transporter]]. At the launch pad, the [[Rotating Service Structure]] allowed payloads to be loaded into the cargo bay on the pad.

At SLC-6, the existing {{convert|5500|ft|m|adj=on}} runway at the North Base was expanded to match the Shuttle Landing Facility in Florida: {{Convert|15000|ft}} in length with additional {{Convert|1000|ft|adj=on}} overruns on both ends to accommodate end-of-mission landings. Just off the runway, was the [[Orbiter Lifting Fixture]], a scaled-down version of the Mate-Demate Device, and the Orbiter Maintenance and Processing Facility (OMPF) where the Shuttle would be refurbished.<ref name="vslc6" /> When the orbiter was ready, the Orbiter Transport System, a 76-wheel transporter would have been used to transport the shuttle between the North Base facilities and SLC-6 over {{Convert|17|mi}} of base and public roadways. The route through the hills around the base required that hills be carved away along {{Convert|2|mi}} of the route to accommodate the orbiter’s wingspan.<ref>{{Cite web |last=Hartenstein |first=William G. |date=2005 |title=Space Shuttle West Coast Launch Site SLC-6, Vandenberg AFB |url=http://www.ktb.net/~billmeco/Slc6a.html |access-date=2024-07-22 |website=Space Photography}}</ref><ref name=":0">{{Cite web |last=Behringer |first=Ashley S. |date=2020-04-09 |title=The Space Shuttle in the Atmosphere |url=https://unwritten-record.blogs.archives.gov/2020/04/09/the-space-shuttle-in-the-atmosphere/ |access-date=2024-07-25 |website=The Unwritten Record |language=en-US}}</ref> At the launch pad, two buildings, the Shuttle Assembly Building and the Mobile Service Tower would envelop the access tower allowing the spacecraft to be stacked right on the launch pad.<ref>{{cite news|last=Toufexis|first=Anastasia|title=Space: New Pad for the Space Shuttle|url=https://content.time.com/time/subscriber/article/0,33009,952355,00.html|date=5 March 1984|access-date=27 September 2022|work=Time}}</ref>

In all, over $4 billion were spent on the modifying SLC-6 for the Space Shuttle. The original Mobile Service Tower (MST) was lowered in height and two new flame ducts were added for the shuttle's [[Space Shuttle Solid Rocket Booster|solid rocket boosters]]. Additional modifications or improvements included liquid hydrogen and liquid oxygen storage tanks, a payload preparation room, payload changeout room, a new launch tower with escape system for the shuttle crew members, sound suppression system and water reclamation area and a Shuttle Assembly Building were added to the original complex.<ref name="vslc6" />[[File:Space Shuttle Enterprise in launch configuration.jpg|thumb|{{OV|101|full=nolink}} at SLC-6 in launch configuration in February 1985]]

Between November 1984 and May 1985, the {{OV|101|full=nolink}} was mated with External Tank and SRBs in [[boilerplate (spaceflight)|boilerplate]] configuration for a series of fit checks like those conducted at [[Kennedy Space Center Launch Complex 39|LC-39]].<ref>{{cite web|title=40 Years Ago: Space Shuttle Enterprise rolls to the Pad|url=https://www.nasa.gov/feature/40-years-ago-space-shuttle-enterprise-rolls-to-the-pad|date=1 May 2019|access-date=26 September 2022|work=NASA.gov}}</ref> SLC-6 was declared operational during acceptance ceremonies held on 15 October 1985.<ref name="lompoc20050929">{{cite news |url=http://lompocrecord.com/news/local/new-era-dawns-for-slc/article_bd0a0f6c-85c7-5d57-b11a-83523377aca9.html |title=New era dawns for SLC-6 |work=[[Lompoc Record]] |first=Janene |last=Scully |date=29 September 2005 |access-date=8 June 2017}}</ref><ref name="telegramtribune19851016">{{cite news |last1=Fulks |first1=Tom |title=Vandeberg opens new space shuttle base |url=https://www.newspapers.com/article/the-tribune-vandeberg-opens-new-space-sh/122247704/ |access-date=4 April 2023 |work=[[The Tribune (San Luis Obispo)|The County-Telegram Tribune]] |date=16 October 1985 |archive-url=https://web.archive.org/web/20230404064312/https://www.newspapers.com/article/the-tribune-vandeberg-opens-new-space-sh/122247704/ |archive-date=4 April 2023 |location=[[San Luis Obispo, California]] |url-status=live |via=Newspapers.com }}</ref> However, much additional work and testing was still required. 

The inaugural polar-orbit flight, designated [[STS-62-A]] and using {{OV|103|full=nolink}} with Shuttle veteran [[Robert Crippen]] as commander, was planned for 15 October 1986. However, the [[Challenger Disaster|''Challenger'' disaster]] of 28 January 1986 grounded the Shuttle fleet as efforts were concentrated on recovery and returning the program to flight after a two-year hiatus.<ref>{{cite web|title=Investigation of the Challenger Accident|url=https://www.govinfo.gov/content/pkg/GPO-CRPT-99hrpt1016/pdf/GPO-CRPT-99hrpt1016.pdf|publisher=Committee on Science and Technology, House of Representatives, Ninety-ninth Congress, Second Session|date=29 October 1986|access-date=27 September 2022}}</ref>

On 31 July 1986, Secretary of the Air Force [[Edward C. Aldridge, Jr.]], announced that Vandenberg's Space Shuttle program would be placed in "operational caretaker status", six months after the Space Shuttle [[Space Shuttle Challenger|''Challenger'']] accident. A few months later, however, SLC-6 was placed in "minimum caretaker status" on 20 February 1987.<ref name=STSaldridge>{{cite book|last=Cleary|first=Mark|title=Military Space Operations - 1971-1992|url=https://spp.fas.org/military/program/cape/cape1-3.htm|access-date=26 September 2022|publisher=USAF 45th Space Wing History Office}}</ref>

Eventually, on 13 May 1988, Secretary Aldridge then directed the Air Force to transfer Space Shuttle assets at Vandenberg to other organizations (specifically, the Kennedy Space Center) by 30 September 1989, the end of the fiscal year. The work was completed 10 days early on 20 September, when SLC-6 was placed in mothball status.<ref name=STSaldridge/>

Several factors accounted for this:<ref name=vslc6/>
* The ''Challenger'' disaster made it clear that sole dependency on the shuttle was unwise
* SLC-6 would have generated more contaminated waste water than originally envisioned, necessitating an expensive treatment plant
* Further study showed more sound suppression water would have been needed, requiring upgraded water supply facilities
* Vehicle icing (which contributed to the ''Challenger'' disaster) would have been more problematic than in Florida, and it was unclear how well SLC-6 facilities would handle that
* Blast protection of nearby occupied buildings was unsatisfactory and more construction would have been required to safeguard them
* Post-''Challenger'', the more confined SLC-6 launch area raised concerns of entrapped gaseous hydrogen causing a fire or explosion
* Large construction cost overruns
* Independent audits found significant construction quality problems that would have been expensive to fix

The Air Force officially terminated the Space Shuttle program at Vandenberg on 26 December 1989. The estimated cost for the discontinued program was $4 billion.<ref>{{cite news|last=Ray|first=Justin|title=From Shuttles to Rockets: Long History for Calif. Launch Pad|url=https://www.space.com/10644-california-launch-pad-history-shuttles-rockets.html|date=19 January 2011|access-date=26 September 2022|work=space.com}}</ref>

The Orbiter Lifting Fixture was relocated to [[United States Air Force Plant 42]] where the orbiters were built and refurbished in [[Palmdale, California]], before the delivery of the {{OV|105|full=nolink}} in 1991. Previously, the orbiters were trucked to Armstrong Flight Research Center at Edwards Air Force Base, about {{Convert|36|mi}} away, which took about 10 hours.<ref name="Discovery Debut">{{Cite web |last=Uri  |first=John |date=16 October 2023 |title=40 Years Ago: Space Shuttle Discovery Makes its Public Debut |url=https://www.nasa.gov/history/40-years-ago-space-shuttle-discovery-makes-its-public-debut/ |access-date=22 July 2024 |website=[[Johnson Space Center]] |language=en-US}}</ref> The Orbiter Lifting Fixture was dismantled in 2008.<ref name="Orbiter Demate from SCA">{{Cite web |date=1 May 2012 |title=Orbiter Mate and Demate to the Shuttle Carrier Aircraft (SCA) at Display Sites |url=http://ksc-lde.ndc.nasa.gov/Linked_Files/Slo_ksc/SLO-KSC-2012-003.pdf |url-status=dead |archive-url=https://web.archive.org/web/20130217015455/http://ksc-lde.ndc.nasa.gov/Linked_Files/Slo_ksc/SLO-KSC-2012-003.pdf |archive-date=17 February 2013 |access-date=22 July 2024 |website=[[NASA]]}}</ref>

The Orbiter Transport System was sent to KSC where it was used to move orbiters between the Orbiter Processing Facility and the Vehicle Assembly Building. The vehicle was purchased by SpaceX in 2014 for $37,075.<ref name=":0" />

===Titan IV (1990–1991) ===
On 6 July 1990, Lockheed Space Operations Company (LSOC) was awarded an Air Force ground system contract to modify SLC-6 into a [[Titan IV]]/[[Centaur (rocket stage)|Centaur]] launch complex—essentially an uprated facility from the original MOL program that would have launched a Titan III vehicle.<ref>{{cite web|title=Federal Consistency Determination Titan IV/Centaur Launch Complex Vandenberg Air Force Base, Santa Barbara County, California|url=https://www.nro.gov/Portals/65/documents/foia/declass/Archive/15-06.PDF
|date=May 1990|publisher=Environmental Solutions, Inc.}}</ref> Site work was scheduled to begin in late-FY 1992 with a planned initial launch capability sometime in FY1996.<ref>{{cite web|title=Topic: Alternate Joint NASA/USAF "STS" System|url=https://forum.nasaspaceflight.com/index.php?topic=36711.60|access-date=27 September 2022|work=NASASpaceFlight.com}}</ref><ref name=t4canx>{{cite web|title=Space Launch Complex 6|url=https://afspacemuseum.org/facilities/space-launch-complex-6/|access-date=27 September 2022|work=Air Force Space & Missile Museum}}</ref>

However, on 22 March 1991, HQ USAF reversed itself again by announcing the termination of the Titan IV/Centaur program at SLC-6.<ref name=t4canx/> The reasons given for the project being canceled was due to "insufficient Titan IV launch requirements from the West Coast to support the construction of a new launch pad." The contract with LSOC was closed out several months later.<ref>{{cite web|title=Titan Missile Facilities|url=http://www.themilitarystandard.com/missile/titan2/facilities.php|access-date=27 September 2022|work=The Military Standard}}</ref> Instead, USAF continued flying military polar orbit satellites using the [[Titan 34D]] and later [[Titan IV]] rockets from [[Vandenberg Space Launch Complex 4|SLC-4E]] at Vandenberg.<ref name=t4canx/><ref>{{cite web|last=Canan|first=James|title=Recovery in Space|url=https://www.airforcemag.com/article/0888space/|date=1 August 1988|access-date=27 September 2022|work=Air Force Magazine}}</ref>

===Athena (1994–1999)===
[[File:LLV-1 ground test.jpg|thumb|Athena 1 sits atop a "milkstool" platform at SLC-6, August 1997.]]

Four [[Athena (rocket family)|Athena]] missions flew from SLC-6, from 1995 to 1999. In the early 1990s, [[Lockheed Missiles and Space Company]] began studies on the prospect of a new family of small launch vehicles for commercial and other users. Lockheed eventually approved the development of the ''Lockheed Launch Vehicle'' (LLV) program in January 1993. After the merger of Lockheed with [[Martin Marietta]], it was renamed ''[[Athena (rocket family)|Athena]].''<ref>{{cite web|last=Day|first=Dwayne|title=Athena rising?|url=https://www.thespacereview.com/article/2234/1#:~:text=It%20originally%20started%20life%20in,it%20had%20a%20rough%20start.|date=11 February 2013|access-date=26 September 2022|work=The Space Review}}</ref>

After another contract was issued in 1994 by the Air Force, modification work began on the existing SLC-6 shuttle launch mount for a small "milkstool" platform to be located over one of the two exhaust ducts originally intended for one of the large solid rocket boosters. The first operational launch from SLC-6 occurred on 15 August 1995, involving the Lockheed-Martin Launch Vehicle I (LMLV-1). Unfortunately, LMLV-1 was terminated in mid-flight after uncontrolled oscillations of the rocket were detected. This resulted in the loss of the vehicle and the payload. The cause of the mishap was later determined to be a guidance system failure coupled with overheating of the booster's first stage steering mechanism. The payload on board was GEMstar 1, a small communications satellite manufactured by CTA, Inc. for the Volunteers in Technical Assistance (VITA), a non-profit organization.<ref>{{cite web|title=GemStar 1 (VITASat 1)|url=https://space.skyrocket.de/doc_sdat/gemstar-1.htm|access-date=26 September 2022|work=Gunter's Space Page}}</ref>

After some hardware redesign and testing, a newly rechristened ''Athena I'' successfully launched NASA's [[Lewis (satellite)|Lewis]] satellite into orbit from SLC-6 on 22 August 1997. Part of NASA's Small Spacecraft Technology Initiative (SSTI) and "Mission to Planet Earth" program.<ref>{{cite web|title=Lewis (SSTI 1)|url=https://space.skyrocket.de/doc_sdat/lewis.htm|access-date=26 September 2022|work=Gunter's Space Page}}</ref>

Another launch, on 24 September 1999, was successful as an ''[[Ikonos]]'' satellite operated by [[Space Imaging]] (later acquired by [[ORBIMAGE]] to form [[GeoEye]]) was successfully placed into a polar orbit using an Athena 2 booster.<ref>{{cite web|title=Launch Details - IKONOS 2 - Athena-2|url=https://www.faa.gov/data_research/commercial_space_data/launch_details/?id=176|access-date=26 September 2022|work=FAA.gov}}</ref>

{{clear}}

===Delta IV (1999–2022)===
[[File:SLC-6 circa 2006.jpg|thumb|Aerial view of SLC-6 circa 2006.]]
Ten [[Delta IV rocket]]s were launched from SLC-6. With the advent of the Delta IV in the late 1990s, [[Boeing|The Boeing Company]] received a lease from the Air Force on 1 September 1999, to modify SLC-6 once again to launch Boeing's [[Delta IV]].<ref>{{cite news|last=Ray|first=Justin|title=Boeing building new launch pad for 21st century|url=https://spaceflightnow.com/news/0003/03slc37bmst/index.html|date=3 March 2000|access-date=25 September 2022|work=Spaceflight Now}}</ref>

Some of the Shuttle-specific components at SLC-6 were removed, such as the mobile Payload Changeout Room, but the Assembly Building, Mobile Service Tower, Launch Tower, [[Flame deflector|flame deflection trenches]] and [[sound suppression system]] and some other shuttle-oriented equipment were retained and made compatible for the new Delta IV rocket. The launch vehicle's [[Common Booster Core]] and associated flight hardware was transported from the Boeing factory in [[Decatur, Alabama|Decatur]], [[Alabama|Ala.]], to Vandenberg aboard the {{Ship|MV|Delta Mariner}} cargo vessel that docked just south of SLC-6 at the same location originally constructed for receiving and offloading space shuttle external tanks.<ref>{{cite web|title=Delta Mariner offloads launch components at Vandenberg|url=https://www.afspc.af.mil/News/Photos/igphoto/2000199749/|archive-url=https://web.archive.org/web/20220927025538/https://www.afspc.af.mil/News/Photos/igphoto/2000199749/|url-status=dead|archive-date=27 September 2022|date=28 October 2011|access-date=26 September 2022|work=afspc.af.mil}}</ref><ref>{{cite news|last=Ray|first=Justin|title=Delta Mariner drops anchor at Vandenberg to deliver rocket|url=https://spaceflightnow.com/2014/11/09/delta-mariner-drops-anchor-at-vandenberg-to-drop-off-rocket/|date=9 November 2014|access-date=26 September 2022|work=Spaceflight Now}}</ref>

[[File:First Delta IV Heavy launch from SLC-6 at Vandenberg AFB.jpg|thumb|Delta IV Heavy launch from SLC-6 with [[USA-224]]]]
Boeing developed the Delta IV class of vehicles as its entrant in the Department of Defense's [[Evolved Expendable Launch Vehicle]] (EELV) program. EELV was intended to cut launch costs and simplify satellite launch processes.

After sitting on the pad since late-2003 and enduring technical issues with both the booster and the payload, the first of the Delta IV launch vehicles to fly from SLC-6 successfully lifted off at 8:33&nbsp;p.m. PDT on 27 June 2006.<ref>{{cite news|title=Delta IV launch successful|url=https://www.af.mil/News/Article-Display/Article/130576/delta-iv-launch-successful/
|date=28 June 2006|access-date=25 September 2022|work=af.mil}}</ref><ref>{{cite news|title=Boeing Completes First Delta IV West Coast Launch|url=http://www.boeing.com/news/releases/2006/q2/060627b_nr.html |archive-url=https://web.archive.org/web/20061110054835/http://www.boeing.com/news/releases/2006/q2/060627b_nr.html |archive-date=10 November 2006 |date=27 June 2006|access-date=26 September 2022|work=Archive.org}}</ref>

The Delta IV Medium+ (4,2) rocket lofted [[NROL]]-22, a classified satellite for the [[National Reconnaissance Office]], into orbit. The payload was successfully deployed approximately 54 minutes later.<ref>{{cite news|last=Cain|first=Fraser|title=First West Coast Delta IV Launch is Successful|url=https://www.universetoday.com/195/first-west-coast-delta-iv-launch-is-successful/|date=28 June 2006|access-date=22 September 2022|work=Universe Today}}</ref> According to a post-launch Boeing News press release, the mission was the first for the NRO aboard a Delta IV and the second aboard a Delta rocket.

Another Delta IV Medium vehicle flew a mission for the Air Force [[Defense Meteorological Satellite Program]], orbiting DMSP-17, on 4 November 2006.<ref>{{cite news|last=Hoy|first=Raymond|title=Delta IV launch successful|url=https://www.afspc.af.mil/News/Article-Display/Article/251497/delta-iv-launch-successful/|archive-url=https://web.archive.org/web/20220926054553/https://www.afspc.af.mil/News/Article-Display/Article/251497/delta-iv-launch-successful/|url-status=dead|archive-date=26 September 2022|date=6 November 2006|access-date=25 September 2022|work=30th Space Wing Public Affairs}}</ref>

The Delta IV and the lease on SLC-6 were turned over to [[United Launch Alliance]] (ULA) when ULA was formed as a joint venture of Boeing and [[Lockheed Martin Space]] in December 2006.

On 20 January 2011, at 1:10&nbsp;p.m. PST, [[USA-224]] (NROL-49) was launched atop a [[Delta IV Heavy]] rocket. The launch was conducted by ULA and was the first flight of a Delta IV Heavy from Vandenberg.<ref>{{cite news|last=Graham|first=William|title=Delta IV Heavy launches on debut West Coast launch with NRO L-49|url=https://www.nasaspaceflight.com/2011/01/live-delta-iv-heavy-launch-nro-l-49/|date=20 January 2011|access-date=25 September 2022|work=NASA Spaceflight}}</ref>

On 24 September 2022, ULA launched the last Delta IV Heavy from the pad, concluding their use of SLC-6.<ref>{{Cite web |last=Clark |first=Stephen |date=23 September 2002|title=Historic launch pad faces uncertain future after final West Coast Delta 4 mission – Spaceflight Now |url=https://spaceflightnow.com/2022/09/23/historic-california-launch-pad-faces-uncertain-future-after-final-west-coast-delta-4-mission/ |access-date=25 September 2022|language=en-US}}</ref> [[Vulcan Centaur]], Delta IV Heavy's successor, will launch from the [[Atlas V]]'s old pad of [[Vandenberg Space Launch Complex 3|SLC-3E]] at Vandenberg.<ref>{{Cite web |last=Erwin |first=Sandra |date=23 September 2022|title=ULA's Delta 4 prepares for final West Coast launch as Vandenberg seeks new tenants |url=https://spacenews.com/ulas-delta-4-prepares-for-final-west-coast-launch-as-vandenberg-officials-seek-new-tenants/ |access-date=25 September 2022|website=SpaceNews |language=en-US}}</ref>

=== SpaceX (from 2023) ===
On 24 April 2023, the [[United States Space Force]] announced that it was leasing SLC-6 to [[SpaceX]] for [[Falcon 9]] and [[Falcon Heavy]] launches.<ref name="spacex-lease">{{cite news |last=Roulette |first=Joey |date=24 April 2023 |title=SpaceX wins approval to add fifth U.S. rocket launch site |url=https://www.reuters.com/technology/space/spacex-wins-approval-add-fifth-us-rocket-launch-site-2023-04-25/ |publisher=Reuters}}</ref><ref>{{Cite news |last=Bergin |first=Chris |date=2023-04-27 |title=SpaceX SLC-6 takeover to mark a new chapter for a famous pad |url=https://www.nasaspaceflight.com/2023/04/spacex-slc-6-takeover/ |access-date=2024-10-19 |language=en-US}}</ref> Prior to its leasing, there was interest among other companies for control over the pad thanks to its large size, most notably by [[Blue Origin]] for their [[New Glenn]] orbital launch vehicle.<ref>{{Cite tweet |number=1645502085297840143 |user=SciGuySpace |title=I'm hearing that Blue Origin is working to take over SLC-6 at Vandenberg Space Force Base. Won't happen until after the Delta IV Heavy is officially retired. Would give New Glenn a West coast launch pad. |first=Eric |last=Berger |date=10 April 2023 |access-date=3 November 2024}}</ref> SpaceX's intentions with the operation of SLC-6 would be using it as a secondary pad at Vandenberg, complimenting their existing facility at [[Vandenberg Space Launch Complex 4|Space Launch Complex 4 East]] (SLC-4E) in a similar method to how [[Kennedy Space Center Launch Complex 39A|LC-39A]] and [[Cape Canaveral Space Launch Complex 40|SLC-40]] are used at Cape Canaveral.<ref name="noozhawk-20231204">{{cite web |last=Scully |first=Janene |date=4 December 2023 |title=SpaceX Yearly Launch Rate at Vandenberg SFB Could Soar to 100 by 2025 |url=https://www.noozhawk.com/spacex-launch-rate-at-vandenberg-sfb-could-soar-to-100-by-2025/ |access-date=5 December 2023 |work=[[Noozhawk]]}}</ref> As part of modifications to the pad, plans call for the demolition of most existing Shuttle and Delta IV-era infrastructure, replacing them with a traditional [[horizontal integration facility]] and [[transporter erector]] setup as seen at SpaceX's other pads.<ref>{{Cite tweet |number=1922139887597175056 |user=alexphysics13 |title=As expected, SpaceX will demolish most of the legacy hardware and buildings from Delta IV Heavy (and Space Shuttle!) at Space Launch Complex 6. SpaceX would still use some buildings like the HIF for rocket integration. |first=Alejandro |last=Romera |date=13 May 2025 |access-date=13 May 2025}}</ref> Since the lease, they have started preparing the launch pad for this reconfiguration, with construction slated to commence in late 2025.<ref>{{Cite web |title=Reconfiguring SLC 6 |url=https://twitter.com/OliverNerd7/status/1754647149466337331 |website=X (Formerly Twitter)}}</ref>

==Launch history==
=== Statistics ===
{{Vandenberg launch pad map|highlight=9}}
{{ #invoke:Chart | bar chart
| float = center
| width = 700
| height = 300
| stack = 1
| group 1 =  1:0:1:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0 <!-- Athena I -->
| group 2 =  0:0:0:0:2: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0 <!-- Athena II -->
| group 3 =  0:0:0:0:0: 0:0:0:0:0: 0:2:0:0:0: 0:0:1:0:0: 0:1:0:1:0: 0:0:0 <!-- Delta IV -->
| group 4 =  0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:1:0:1:0: 0:0:0:0:1: 0:1:1 <!-- Delta IV Heavy -->
| group 5 =  0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0 <!-- Falcon 9-->
| group 6 =  0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0:0:0: 0:0:0 <!-- Falcon Heavy -->
| colors = MediumAquamarine : MediumSeaGreen : LightSteelBlue : DarkBlue: IndianRed : DarkRed
| group names = [[Athena I]] : [[Athena II]] : [[Delta IV]] : [[Delta IV Heavy]]: [[Falcon 9]]: [[Falcon Heavy]]
| x legends = 1995::::: 2000::::: 2005::::: 2010::::: 2015::::: 2020::
| y tick marks = 2
| units suffix = _launches
}}

=== List of launches ===
All Athena launches operated by [[Lockheed Martin]]. All launches in 2006 operated by [[Boeing]]. All launches from 2011 to 2022 operated by [[United Launch Alliance]].
{| class="wikitable" style="margin: 1em 1em 1em 0"
! No.
! Date
!Time<br />([[UTC]])
! Launch vehicle
!Configuration
! Payload
! Outcome
! Remarks
|-
!1
|15 August 1995
|22:30
|[[Athena I]]
|N/A
|GemStar 1
|{{Failure}}
|First launch from SLC-6. Maiden flight of the Athena I and of the Athena family. Thrust Vector control system failure led to [[range safety]] protocols 160 seconds after launch.
|-
!2
|23 August 1997
|06:51
|[[Athena I]]
|N/A
|[[Lewis (satellite)|Lewis]]
|{{Success}}
|Part of the Small Satellite Technology Initiative, aiming to conduct [[Earth observation]] and [[ultraviolet astronomy]]. Launch was a success, but improper modification of altitude control system led to loss of signal three days into operation.
|-
!3
|27 April 1999
|18:22
|[[Athena II]]
|N/A
|[[Ikonos|IKONOS 1]]
|{{Failure}}
|First Athena II flight from SLC-6. [[Payload fairing]] failed to separate and satellite did not achieve orbit.
|-
!4
|24 September 1999
|18:21
|[[Athena II]]
|N/A
|[[Ikonos|IKONOS 2]]
|{{Success}}
|Final flight of the Athena II and last Athena launch from SLC-6.
|-
!5
|28 June 2006
|03:33
|[[Delta IV]]
|Medium+ (4,2)
|[[USA-184|NROL-22]]
|{{Success}}
|[[List of NRO launches|NRO launch]]. [[Trumpet (satellite)|Trumpet]] satellite, also known as USA-184. First launch for the [[National Reconnaissance Office]] on a Delta IV. First Delta IV launch from Vandenberg, and first military launch from SLC-6.<ref>{{Cite web|url=http://www.spaceflightnow.com/delta/d317/ |title=New era of rocket launches begins at California base |author= Justin Ray |publisher=Spaceflight Now |date=27 June 2006 |access-date=12 December 2010 }}</ref>
|-
!6
|4 November 2006
|13:53
|[[Delta IV]]
|Medium
|USA-192 ([[Defense Meteorological Satellite Program|DMSP]] F17)
|{{Success}}
|
|-
!7
|20 January 2011
|21:10
|[[Delta IV Heavy]]
|Heavy
|[[USA-224|NROL-49]]
|{{Success}}<ref name=d352>{{cite web|title=United Launch Alliance Launches First West Coast Delta IV Heavy Mission|url=http://www.ulalaunch.com/site/pages/News.shtml#/63|publisher=[[United Launch Alliance]]|access-date=21 January 2011|date=20 January 2011|archive-url=https://web.archive.org/web/20131207160150/http://www.ulalaunch.com/site/pages/News.shtml#/63|archive-date=7 December 2013|url-status=dead}}</ref>
|[[List of NRO launches|NRO launch]]. [[KH-11 KENNEN|KH-11]] satellite, also known as USA-224. First Delta IV Heavy launch from Vandenberg.<ref name="d352" />
|-
!8
|2 April 2012
|23:04
|[[Delta IV]]
|Medium+ (5,2)
|[[USA-234|NROL-25]]
|{{Success}}
|[[List of NRO launches|NRO launch]]. [[Future Imagery Architecture|Topaz]] satellite, also known as USA-234.
|-
!9
|28 August 2013
|18:03
|[[Delta IV Heavy]]
|Heavy
|[[USA-245|NROL-65]]
|{{Success}}<ref name=d364>{{cite web|title=National Reconnaissance Office Mission Successfully Launches on World's Largest Rocket, the United Launch Alliance Delta IV Heavy|url=http://www.ulalaunch.com/site/pages/News.shtml#/152/|publisher=[[United Launch Alliance]]|access-date=29 August 2013|date=28 August 2013|archive-url=https://web.archive.org/web/20131207160150/http://www.ulalaunch.com/site/pages/News.shtml#/152/|archive-date=7 December 2013|url-status=dead}}</ref>
|[[List of NRO launches|NRO launch]]. [[KH-11 KENNEN|KH-11]] satellite, also known as USA-245.
|-
!10
|10 February 2016
|11:40
|[[Delta IV]]
|Medium+ (5,2)
|[[List of NRO launches|NROL-45]]
|{{Success}}<ref>{{cite web|title=United Launch Alliance Successfully Launches NROL-45 Payload for the National Reconnaissance Office|url=http://www.ulalaunch.com/ula-successfully-launches-nrol45.aspx?title=United+Launch+Alliance+Successfully+Launches+NROL-45+Payload+for+the+National+Reconnaissance+Office&Category=1|publisher=[[United Launch Alliance]]|access-date=29 March 2016|date=10 February 2016}}</ref>
|[[National Reconnaissance Office|NRO]] launch. [[Future Imagery Architecture|Topaz]] satellite, also known as USA-267.
|-
!11
|12 January 2018
|22:11
|[[Delta IV]]
|Medium+ (5,2)
|[[List of NRO launches|NROL-47]]
|{{Success}}
|[[National Reconnaissance Office|NRO]] launch. [[Future Imagery Architecture|Topaz]] satellite, also known as USA-281. Final Delta IV Medium launch from Vandenberg.
|-
!12
|19 January 2019
|11:10
|[[Delta IV Heavy]]
|Heavy
|[[List of NRO launches|NROL-71]]
|{{Success}}
|[[National Reconnaissance Office|NRO]] launch. [[KH-11 KENNEN|KH-11]] satellite, also known as USA-290.
|-
!13
|26 April 2021
|20:47
|[[Delta IV Heavy]]
|Heavy
|[[List of NRO launches|NROL-82]]
|{{Success}}
|[[National Reconnaissance Office|NRO]] launch. [[KH-11 KENNEN|KH-11]] satellite, also known as USA-314.
|-
!14
|24 September 2022
|22:25
|[[Delta IV Heavy]]
|Heavy
|[[List of NRO launches|NROL-91]]
|{{Success}}
|[[National Reconnaissance Office|NRO]] launch. [[KH-11 KENNEN|KH-11]] satellite, also known as USA-338. Final Delta IV launch from SLC-6, and last flight of a Delta rocket from Vandenberg.
|}

==References==
{{reflist}}

==External links==
* [https://web.archive.org/web/20060629070100/http://www.boeing.com/defense-space/space/delta/delta4/nro_l-22/index.html Boeing Media Kit for Delta IV Launch of NROL-22]
* [https://web.archive.org/web/20060423193232/http://www.vandenberg.af.mil/~swStaff/history/chronology.asp History/Chronology of Vandenberg AFB]
* [https://web.archive.org/web/20051125201133/http://www.boeing.com/companyoffices/gallery/images/space/delta_iv/delta_iv_vafb.htm Boeing Corporation's Delta IV Space Launch Complex Six photo gallery]
* [http://www.lighthousefriends.com/light.asp?ID=645 LighthouseFriends.com - Point Arguello]
* [https://web.archive.org/web/20071022141931/http://www.capcomespace.net/dossiers/espace_US/shuttle/vandenberg/SLC6%201979.htm Space Shuttle SLC-6 Chronology (in French)] - Capcomespace.net
* [http://www.ktb.net/~billmeco/Slc6a.html Vandenberg Space Shuttle Operations] - featuring space photography of [http://www.ktb.net/~billmeco/ William G. Hartenstein]

{{commons category-inline|Vandenberg Space Force Base Space Launch Complex 6}}

{{Vandenberg}}
{{Thor and Delta rockets}}
{{Space Shuttle}}{{SpaceX}}{{DEFAULTSORT:Vandenberg SFB Space Launch Complex 6}}
[[Category:Vandenberg Space Force Base]]
[[Category:Launch complexes of the United States Space Force]]