Space Launch Complex 4 (SLC-4) is a launch and landing site at

Vandenberg Space Force Base Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...

, California, U.S. It has two pads, both of which are used by

SpaceX Space Exploration Technologies Corp., commonly referred to as SpaceX, is an America, American space technology company headquartered at the SpaceX Starbase, Starbase development site in Starbase, Texas. Since its founding in 2002, the compa ...

for

Falcon 9 Falcon 9 is a Reusable launch system#Partial reusable launch systems, partially reusable, two-stage-to-orbit, medium-lift launch vehicle designed and manufactured in the United States by SpaceX. The first Falcon 9 launch was on June 4, 2010, an ...

, one for launch operations, and the other as Landing Zone 4 (LZ-4) for SpaceX landings. The complex was previously used by

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and

Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

rockets between 1963 and 2005. It consisted of two launch pads: Space Launch Complex 4 West (SLC-4W, formerly PALC-2-3) and Space Launch Complex 4 East (SLC-4E, formerly PALC-2-4). Both pads were built for use by

Atlas-Agena The Atlas-Agena was an American expendable launch system derived from the SM-65 Atlas missile. It was a member of the Atlas (rocket family), Atlas family of rockets, and was launched 109 times between 1960 and 1978. It was used to launch the first ...

rockets, but were later rebuilt to handle Titan rockets. The designation SLC-4 was applied at the time of the conversion to launch Titan launch vehicles. Both pads at Space Launch Complex 4 are currently leased by SpaceX. SLC-4E is leased as a launch site for the

rocket, which first flew from Vandenberg on 29 September 2013, following a 24-month refurbishment program which had started in early 2011. SpaceX began a five-year lease of Launch Complex 4 West in February 2015 in order to use that area as a ''landing'' pad to bring back VTVL return-to-launch-site (RTLS) first-stage boosters of the reusable Falcon 9 launch vehicle. That pad was later named by SpaceX as Landing Zone 4 and first used operationally for a

booster landing in 2018.

SLC-4E

Atlas-Agena

The first launch from PALC2-4 occurred on 14 August 1964, when a KH-7 satellite was launched by an Atlas-Agena D. After 27 Atlas-Agena launches, the last of which was on 4 June 1967, the complex was deactivated. Titan IIID rocket

Titan IIID

During 1971 the complex was reactivated and refurbished for use by the

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Titan III launch vehicles. The Titan IIID made its maiden flight from SLC-4E on 15 June 1971, launching the first KH-9 Hexagon satellite. The first KH-11 Kennan satellite was launched from the complex on 19 December 1976. All 22 Titan IIIDs were launched from SLC-4E, with the last occurring on 17 November 1982.

Titan 34D

The complex was then refurbished to accommodate the

Titan 34D. Seven Titan 34Ds were launched between 20 June 1983, and 6 November 1988. SLC-4E hosted one of the most dramatic launch accidents in US history when a Titan 34D-9 carrying a KH-9 photoreconnaissance satellite exploded a few hundred feet above the pad on 18 April 1986. The enormous blast showered the launch complex with debris and toxic propellant (hydrazine and dinitrogen tetroxide), resulting in extensive damage. 16 months after the accident, the pad was back in commission when it hosted a successful launch of a KH-11 satellite. Final Titan IV launch

Titan IV

The last Titan variant to use the complex was the Titan IV, starting on 8 March 1991, with the launch of Lacrosse 2. On 19 October 2005, the last flight of a Titan rocket occurred, when a Titan IVB was launched from SLC-4E, with an Improved Crystal satellite. Following this launch, the complex was deactivated, having been used for 68 launches. SpaceX_Falcon_9

Falcon 9

refurbished SLC–4E for

launches in a 24-month process that began in early 2011. The draft

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with a finding of "no significant impact" was published in February 2011. Demolition began on the pad's fixed and mobile service towers in summer 2011. By late 2012, SpaceX anticipated that the initial launch from the Vandenberg pad would be in 2013, with the larger variant Falcon 9 v1.1. As the pad was nearing completion in February 2013, the first launch was scheduled for summer 2013, but was delayed until September 2013.

Launch history

Statistics

Atlas-Agena (1964–1967)

All flights operated by the

United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

Titan IIID and 34D (1971–1988)

All flights operated by the

Titan IV (1991–2005)

All flights operated by the

Falcon 9 (since 2013)

All flights operated by

Upcoming launches

SLC-4W

SLC-4W started operations in 1963 as Space Launch Complex 4W, and continued as an operational launch site through 2003. In 2015, SpaceX started conversion of the launch site into Landing Zone LZ-4. Landing operations commenced in 2018 at LZ-4.

SLC-4W launch history

Statistics

By rocket type

= Atlas-Agena

= The first launch to use what is now SLC-4 occurred on 12 July 1963, when an Atlas LV-3 Agena-D launched the first

KH-7 Gambit BYEMAN codenamed GAMBIT, the KH-7 (Air Force Program 206) was a reconnaissance satellite used by the United States from July 1963 to June 1967. Like the older Corona (satellite), CORONA system, it acquired imagery intelligence by taking photog ...

reconnaissance satellite, from PALC-2-3. Twelve Atlas-Agenas launches were conducted from PALC-2-3, with the last occurring on 12 March 1965.

= Titan IIIB

= Following this, it was rebuilt as SLC-4W, a Titan launch complex. The first Titan launch from SLC-4W was a Titan IIIB, on 29 July 1966. All 68 Titan IIIB launches occurred from SLC-4W, with the last on 12 February 1987. Titan 23G rocket

= Titan 23G

= After the retirement of the Titan IIIB, it became a Titan 23G launch site, and twelve Titan II launches, using the 23G orbital configuration, were conducted between 5 September 1988 and 18 October 2003. Following the retirement of the Titan 23G, SLC-4W was deactivated. 93 rockets were launched from SLC-4W. SLC-4W was the site of the launch of Clementine, the only spacecraft to be launched from Vandenberg to the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

, which was launched by a Titan 23G on 25 January 1994.

Launch timeline 1963–2003

All flights prior to November 1963 operated by the

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. All flights afterwards operated by the

LZ-4

Development history

signed a five-year lease of Launch Complex 4W in February 2015, in order to use the area to land reusable launch vehicles at the pad. The location is being used for vertical landing of Return-To-Launch-Site (RTLS) first-stage boosters of the

rockets that are launched from the adjacent SLC-4E launch pad. This novel use of SLC-4W had initially surfaced in July 2014 when '' NASASpaceFlight.com'' published that SpaceX was considering leasing SLC-4W for use as a RTLS vertical-landing facility for reusable first-stage boosters. Principal structures on the pad were demolished in September 2014 as construction of the landing pad began and was completed sometime around 2017.

Landing statistics

Landing outcomes (Falcon 9)

Detailed landing history

After performing return-to-launch-site (RTLS) landings at its two Cape Canaveral Space Force Station landing pads, Landing Zones 1 and 2, the company initially planned to attempt the first West Coast booster landing at Vandenberg AFB with the fourth Iridium NEXT satellite launch in December 2017, but ultimately opted for an expendable mission. In July 2018, SpaceX filed an FCC permit to communicate with a Falcon 9 first stage post-landing at SLC-4W, hinting at a potential RTLS landing, for the SAOCOM 1A mission. This launch was later rescheduled to October 8, 2018. Publicly announced through FCC permits and sonic boom warnings, SpaceX renamed SLC-4W as Landing Zone 4 ahead of the first landing attempt. The landing of a Falcon 9 first stage booster successfully occurred at Landing Zone 4 in October 2018, following the launch of the Argentinian SAOCOM 1A satellite.

Notes

References

External links

* * {{SpaceX Vandenberg Space Force Base SpaceX facilities Space Launch Complex 4 Space Launch Complex 4