Space Launch Complex 3 (SLC-3) is a launch site at Vandenberg Space Force Base that consists of two separate launch pads. Space Launch Complex 3 East (SLC-3E) was used by the Atlas V launch vehicle before it was decommissioned in August 2021 with the final launch taking place on November 10, 2022, at 09:49, while Space Launch Complex 3 West (SLC-3W) has been demolished.

Launches from Vandenberg fly southward, allowing payloads to be placed in high-inclination orbits such as polar or Sun-synchronous orbit, which allow full global coverage on a regular basis and are often used for weather, Earth observation, and reconnaissance satellites. These orbits are difficult to reach from Cape Canaveral Space Force Station, where launches must fly eastward due to major population centers to both the north and south of Kennedy Space Center. Avoiding these would require hugely inefficient maneuvering, greatly reducing payload capacity.

SLC-3E was the launch site of the Mars lander InSight in May 2018.

SLC-3E One of two Atlas-Agena pads at VAFB, SLC-3E was originally the designated facility for MIDAS (Missile Defense Alarm System) launches and hosted its first flight on July 12, 1961. After the MIDAS program ended in 1966, SLC-3E then hosted reentry vehicle tests in 1967–68 as part of Project PRIME. The pad was mothballed for a decade, then returned to use in the late 1970s for NAVSTAR communications satellites on refurbished Atlas E/F missiles. On December 19, 1981, Atlas 76E crashed a few hundred feet from the pad after an engine failure, but no serious damage resulted to facilities. SLC-3E was then converted for the Atlas H (Atlas-Centaur core with a solid upper stage in place of the Centaur) and hosted ELINT satellite launches from 1983 to 1987. The pad was mothballed once again and not used for the next 12 years, when it was revived for the Atlas IIAS.

Three successful Atlas IIAS missions were flown from SLC-3E. The first mission, flown on December 18, 1999, launched the Terra satellite.NASA – NSSDC – Spacecraft – Details . NASA. The other two launched satellites in the Naval Ocean Surveillance System, USA 160 and USA 173.NASA – NSSDC – Spacecraft – Details. NASA.NASA – NSSDC – Spacecraft – Details . NASA. The final Atlas IIAS mission from SLC-3E was launched on December 2, 2003.

It was reported in 2003 that SLC-3E would be overhauled to serve as a launch platform for the Atlas V. Renovations of SLC-3E began after a January 2004 ground breaking ceremony. Along with other work, the Mobile Service Tower roof was raised by approximately to a height of to accommodate an Atlas V 500 series vehicle with its larger payload fairing. In July 2004, Lockheed Martin announced the arrival of the fourth and final segment of the fixed launch platform (FLP). The segments had been transported from a fabrication facility in Oak Hill, FL, away. The largest segment weighed 90 tons and was "thought to be the biggest over-the-road shipment ever attempted cross-country." In February 2005, the activation team handed over the launch pad to the operational team, marking the end of major reconstruction. The first Atlas V launch from SLC-3E took place at 10:02 GMT on March 13, 2008.

United Launch Alliance (ULA) inherited the pad in December 2006 when the company was formed as the joint venture of Lockheed Martin and Boeing, and continued to use it to fly Atlas V rockets. In October 2015 ULA announced that the pad would be updated to accommodate the upcoming Vulcan Centaur rocket, with the pad then being able to launch either Atlas V or Vulcan. The final Atlas V launch from the pad took place on November 10, 2022, carrying the JPSS-2 satellite. The first flight of Vulcan from SLC-3E was anticipated to be in 2023, but Vulcan has been delayed and the first flight from SLC-3E is now expected in 2025. Conversion work to support Vulcan Centaur is ongoing and completion is expected in 2025.

SLC-3W SLC-3W was originally built for Atlas-Agena launches and the first flight off the pad was the launch of Samos 1 on October 11, 1960. The facility was extensively damaged 11 months later when Samos 3's booster exploded on the pad, but it was repaired quickly and hosted its next launch slightly under two months afterwards.

In 1962–63, the pad was converted for Thor-Agena use and was the primary launching site for Corona reconnaissance satellites for the next decade. After the Corona program ended in 1972, SLC-3W was converted back to support Atlases, this time flights of refurbished Atlas E/F missiles. The final such launch took place in 1995.

SpaceX initially planned to use SLC-3W for the Falcon 1 launch vehicle but switched to SLC-4E with Falcon 9.Federal Register /Vol. 73, No. 245 / Friday, December 19, 2008 / Proposed Rules, page 77579.

Launch statistics

SLC-3E

Early Atlas All launches from 1961 to 1963 operated by the United States Navy. All launches since 1965 operated by the United States Air Force. No.DateTime (UTC)Launch vehicleConfigurationPayloadResultRemarks112 July 196115:11Atlas-AgenaAtlas LV-3 / Agena-AMIDAS 3First launch from PALC-1-2.221 October 196113:53Atlas-AgenaAtlas LV-3 / Agena-BMIDAS 4Roll control failed 186 seconds following launch, placing satellite in an incorrect orbit.322 December 196119:12Atlas-AgenaAtlas LV-3 / Agena-BSamos 5Sustainer engine cutoff failed, leading to Atlas burn to continue until fuel depletion, placing satellite in higher than expected orbit.47 March 196222:10Atlas-AgenaAtlas LV-3 / Agena-BSamos 659 April 196215:04Atlas-AgenaAtlas LV-3 / Agena-BMIDAS 5Rocket underwent improper pitch program, placing payload in incorrect orbit.617 December 196220:36Atlas-AgenaAtlas LV-3 / Agena-BMIDAS 6Hydraulic heat shield failed at liftoff, leading to loss of booster engine hydraulic fluid. Range safety protocols engaged 80 seconds after launch.79 May 196320:06Atlas-AgenaAtlas LV-3 / Agena-BMIDAS 7812 June 1963UnknownAtlas-AgenaAtlas LV-3 / Agena-BMIDAS 8919 July 196303:51Atlas-AgenaAtlas LV-3 / Agena-BMIDAS 9109 June 196620:15Atlas-AgenaAtlas SLV-3 /Agena-DMIDAS 10First launch as SLC-3 and as SLC-3E. First Atlas SLV launch from the complex. Agena engine relight failed, placing satellite in incorrect orbit.1119 August 196619:30Atlas-AgenaAtlas SLV-3 /Agena-DMIDAS 11125 October 196622:00Atlas-AgenaAtlas SLV-3 /Agena-DMIDAS 121321 December 196622:15Atlas SLV-3Atlas SLV-3PRIMESuborbital launch. First of three test flights of the X-23 PRIME.145 March 196723:05Atlas SLV-3Atlas SLV-3PRIMESuborbital launch. Second of three test flights of the X-23 PRIME.1520 April 196701:35Atlas SLV-3Atlas SLV-3PRIMESuborbital launch. Third of three test flights of the X-23 PRIME.1616 August 196820:57Atlas-BurnerAtlas SLV-3 /Burner 2STP P68-1Maiden flight of the Atlas-Burner and only flight from SLC-3E. Payload fairings failed to separate, leading to failure to reach orbit.1722 February 197823:44Atlas E/FAtlas E/F / SVSOPS-5111 (GPS-1)First Atlas E/F flight from SLC-3E. First launch of the Global Positioning System.1813 May 197810:34Atlas E/FAtlas E/F / SVSOPS-5112 (GPS-2)Part of the Global Positioning System.197 October 197800:28Atlas E/FAtlas E/F / SVSOPS-5113 (GPS-3)Part of the Global Positioning System.2011 December 197803:59Atlas E/FAtlas E/F / SVSOPS-5114 (GPS-4)Part of the Global Positioning System.219 February 198023:08Atlas E/FAtlas E/F / SVSOPS-5117 (GPS-5)Part of the Global Positioning System.2226 April 198022:00Atlas E/FAtlas E/F / SVSOPS-5118 (GPS-6)Part of the Global Positioning System.2319 December 198101:10Atlas E/FAtlas E/F / SVSGPS-7Part of the Global Positioning System. Sealant covering gas generator caused premature shutdown of a booster engine 7 seconds after launch, activating RSO protocols just before hitting the ground. Last Atlas E/F launch from SLC-3E.249 February 198313:47Atlas HAtlas H / MSDOPS-0252 (NOSS-5)Maiden flight of the Atlas H.259 June 198323:23Atlas HAtlas H / MSDOPS-6432 (NOSS-6)265 February 198418:44Atlas HAtlas H / MSDOPS-8737 (NOSS-7)279 February 198610:06Atlas HAtlas H / MSDUSA-15 to USA-18 (NOSS-8)2815 May 198715:45Atlas HAtlas H / MSDUSA-22 to USA-25 (NOSS-9)Last flight of the Atlas H.

Atlas II and Atlas V All Atlas II launches operated by Lockheed Martin. All Atlas V launches operated by United Launch Alliance. No.DateTime (UTC)Launch vehicleConfigurationPayloadResultRemarks2918 December 199918:57Atlas IIAtlas IIASTerraPart of the Large Strategic Science Missions, aimed at studying Earth's climate. First civilian launch from SLC-3E, first Atlas II launch from Vandenberg, and first flight of a Centaur upper stage from Vandenberg.308 September 200115:25Atlas IIAtlas IIASNROL-13NRO launch. Two Intruder satellites, sharing the designation USA-160. First launch from SLC-3E acknowledged by the National Reconnaissance Office.312 December 200310:04Atlas IIAtlas IIASNROL-18NRO launch. Two Intruder satellites, sharing the designation USA-173. Last Atlas II flight from Vandenberg.3213 March 200810:02Atlas VAtlas V 411NROL-28NRO launch. Trumpet satellite, also known as USA-200. First Atlas V flight from Vandenberg.3318 October 200916:12Atlas VAtlas V 401USA-210 (DMSP 5D3-F18)3421 September 201004:03Atlas VAtlas V 501NROL-41NRO launch. Topaz satellite, also known as USA-215. First launch of the Atlas V 500 configuration from SLC-3E.3515 April 201104:24Atlas VAtlas V 411NROL-34NRO launch. Two Intruder satellites, sharing the designation USA-229.3613 September 201221:39Atlas VAtlas V 401NROL-36NRO launch. Two Intruder satellites, sharing the designation USA-238.3711 February 201318:02Atlas VAtlas V 401Landsat 8Part of the Landsat program, aimed at providing research-oriented photographs of Earth. First civilian Atlas V launch from Vandenberg.386 December 201307:04Atlas VAtlas V 501NROL-39NRO launch. Topaz satellite, also known as USA-247. Flight became notable for its patch featuring an octopus on a globe with the motto "Nothing is Beyond Our Reach," which generated controversy following the 2013 Global surveillance disclosures.393 April 201414:46Atlas VAtlas V 401USA-249 (DMSP-5D3 F19)Final launch of the Defense Meteorological Satellite Program.4013 August 201418:30Atlas VAtlas V 401WorldView-3First commercial launch from SLC-3E.4113 December 201403:19Atlas VAtlas V 541NROL-35NRO launch. Trumpet satellite, also known as USA-259.428 October 201512:49Atlas VAtlas V 401NROL-55NRO launch. Two Intruder satellites, sharing the designation USA-264.4311 November 201618:30Atlas VAtlas V 401WorldView-4441 March 201717:49Atlas VAtlas V 401NROL-79NRO launch. Two Intruder satellites, sharing the designation USA-274.4524 September 201705:49Atlas VAtlas V 541NROL-42NRO launch. Trumpet satellite, also known as USA-278. Last flight of the Atlas V 500 configuration from SLC-3E.465 May 201811:05Atlas VAtlas V 401InSight and Mars Cube OnePart of the Discovery Program, aiming to study the interior of Mars. First interplanetary launch from Vandenberg, and first flight to another celestial body from SLC-3E.4727 September 202118:12Atlas VAtlas V 401Landsat 9Part of the Landsat program, aimed at providing research-oriented photographs of Earth.4810 November 202209:49Atlas VAtlas V 401NOAA-21 and LOFTIDPart of the Joint Polar Satellite System for NOAA-21, aimed at providing environmental data used in numerical weather prediction. Inflatable heat shield test for LOFTID. Last flight of the Atlas V 400 configuration, and final Atlas launch from Vandenberg.

SLC-3W

Early Atlas and Thor All launches from 1960 to 1962 operated by the United States Navy. All launches since 1966 operated by the United States Air Force.