Space Launch Complex 37 (SLC-37), previously Launch Complex 37 (LC-37), is a launch complex on

Cape Canaveral Space Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the sta ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. Originally built to support the

Apollo program The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which Moon landing, landed the first humans on the Moon in 1969. Apollo followed Project Mercury that put the first Americans in sp ...

, the complex consists of two launch pads: LC-37A and SLC-37B. Pad 37A has never been used, while 37B hosted

Saturn I The Saturn I was a rocket designed as the United States' first medium lift launch vehicle for up to low Earth orbit Payload (air and space craft), payloads.Terminology has changed since the 1960s; back then, 20,000 pounds was considered "heavy l ...

and

Saturn IB The Saturn IB (also known as the uprated Saturn I) was an American launch vehicle commissioned by the National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage (, 43,3 ...

launches in the 1960s as well as

Delta IV Delta IV was a group of five expendable launch systems in the Delta rocket family. It flew 45 missions from 2002 to 2024. Originally designed by Boeing's Defense, Space and Security division for the Evolved Expendable Launch Vehicle (EELV) p ...

and

Delta IV Heavy The Delta IV Heavy (Delta 9250H) was an expendable heavy-lift launch vehicle, the largest type of the Delta IV family. It had the highest capacity of any operational launch vehicle in the world after the retirement of the Space Shuttle in 20 ...

launches from 2002 to 2024. Currently, the pad is not officially leased to anyone. However,

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 ...

is expected to become the next tenant of SLC-37 for use as a launch site for

Starship A starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for interstellar travel, traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" appears as early as 1 ...

, so far possessing a limited

right of entry Right of entry refers to one's right to take or resume possession of land, or the right of a person to go onto another's real property without committing trespass. It also refers to a grantor's power to retake real estate from a grantee A grant ...

and a draft

environmental impact statement An environmental impact statement (EIS), under United States environmental law, is a document required by the 1969 National Environmental Policy Act (NEPA) for certain actions "significantly affecting the quality of the human environment". An E ...

History

Saturn I and IB (1964–1968)

Launch Complex 37 began construction in 1959, being envisioned to be a second site to launch the experimental heavy-lift

Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...

rockets, joining Launch Complex 34 (LC-34) to the south. Originally, it was planned to be the launch site for an Earth orbit rendezvous (EOR) strategy to potentially be taken by the Apollo program, where a launch vehicle such as the Saturn C-3 would launch both the

trans-lunar injection A trans-lunar injection (TLI) is a propulsive maneuver, which is used to send a spacecraft to the Moon. Typical lunar transfer trajectories approximate Hohmann transfers, although low-energy transfers have also been used in some cases, as with ...

stage and the Lunar Excursion Module from the two pads, while the crew would lift off from LC-34 and intercept the two payloads in

low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

. Despite

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

opting for a

Lunar orbit rendezvous Lunar orbit rendezvous (LOR) is a process for landing humans on the Moon and returning them to Earth. It was utilized for the Apollo program missions in the 1960s and 1970s. In a LOR mission, a main spacecraft and a lunar lander travel to lunar or ...

(LOR) approach and using the

Saturn V The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had multistage rocket, three stages, and was powered by liquid-propel ...

from

Launch Complex 39 Launch Complex 39 (LC-39) is a rocket launch site at the John F. Kennedy Space Center on Merritt Island, Florida, Merritt Island in Florida, United States. The site and its collection of facilities were originally built as the Apollo program's ...

to the north, they nonetheless accepted LC-37 to support the Saturn I program in 1963. Apollo 5 on pad

The original layout of the launch complex featured one Mobile Service Structure which could be used to service or mate a rocket on either LC-37A or 37B, but not on both simultaneously. The first launch from LC-37 came on January 29, 1964, launching Saturn I SA-5 as part of the rocketry development portion of the Apollo program. Over the next two years, a total of six uncrewed Saturn I flights were launched from the complex, mostly carrying boilerplate Apollo capsules alongside the three launches of the

Pegasus Pegasus (; ) is a winged horse in Greek mythology, usually depicted as a white stallion. He was sired by Poseidon, in his role as horse-god, and foaled by the Gorgon Medusa. Pegasus was the brother of Chrysaor, both born from Medusa's blood w ...

project. In late 1965, both LC-37 and LC-34 were modified to launch the Saturn I's successor, the

. Similarly to its previous configuration, this was in support of Apollo development before the Saturn V's activation at

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...

; however, the original purpose of EOR was also made ready as a backup in case complications render the Saturn V and LOR unfeasible. Only two Saturn IB launches were made from LC-37: the first one was

AS-203 AS-203 (also known as SA-203 or Apollo 3) was an uncrewed flight of the Saturn IB rocket on July 5, 1966. It carried no command and service module, as its purpose was to verify the design of the S-IVB rocket stage restart capability that would l ...

(or informally Apollo 3), which launched on July 5, 1966 and tested engine restart capabilities on the

S-IVB The S-IVB (pronounced "S-four-B") was the third stage on the Saturn V and second stage on the Saturn IB launch vehicles. Built by the Douglas Aircraft Company, it had one J-2 rocket engine. For lunar missions it was fired twice: first for Earth ...

upper stage. The second one was

Apollo 5 Apollo 5 (launched January 22, 1968), also known as AS-204, was the uncrewed first flight of the Apollo Lunar Module (LM) that would later carry astronauts to the surface of the Moon. The Saturn IB rocket bearing the LM lifted off from ...

, lifting off on January 22, 1968 and carrying the first operational test of the

Apollo Lunar Module The Apollo Lunar Module (LM ), originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed sp ...

in space. The facility was deactivated in 1972, following the conclusion of the Apollo program. Proposals were drawn of resuming Saturn IB launches from LC-37 and LC-34 as part of the

Apollo Applications Program The Apollo Applications Program (AAP) was created as early as 1966 by NASA headquarters to develop science-based human spaceflight missions using hardware developed for the Apollo program. AAP was the ultimate development of a number of official ...

, but NASA instead opted to modify

Launch Complex 39B Launch Complex 39B (LC-39B) is the second of Launch Complex 39's three launch pads, located at NASA's Kennedy Space Center in Merritt Island, Florida. The pad, along with Launch Complex 39A, was first designed for the Saturn V launch vehicle, ...

for that role. LC-37 would sit dormant for the next 30 years.

Delta IV and Delta IV Heavy (2002–2024)

In 1998, 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 ...

and

Boeing The Boeing Company, or simply Boeing (), is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, and missiles worldwide. The company also provides leasing and product support s ...

came into an agreement to use LC-37 for launching the

as part of the

Evolved Expendable Launch Vehicle National Security Space Launch (NSSL) is a program of the United States Space Force (USSF) intended to assure access to space for United States Department of Defense and other United States government payloads. The program is managed by the Assure ...

program, getting rechristened as SLC-37 as a result of doing so. Having acquired the Delta family following their merger with

McDonnell Douglas McDonnell Douglas Corporation was a major American Aerospace manufacturer, aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own ...

the previous year, Boeing aimed for the Delta IV to be a complement and not a replacement to the other active members of the time, the

Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family, derived directly from the Delta 3000, and entered service in ...

and

Delta III Delta III was an expendable launch vehicle made by McDonnell Douglas (later acquired by Boeing). Development was canceled before the vehicle became operational. The vehicle is the third generation of the Delta rocket family, developed from the ...

. As such (and taking the difference in lift capabilities into account), a new launch site similar in size to SLC-37 was needed rather than continuing to use Space Launch Complex 17 (SLC-17). Facility modifications were made to SLC-37B in 2001, constructing a tall Mobile Service Tower fitted to service all planned Delta IV configurations. The complex was officially put into active service with the first launch of the Delta IV on November 20, 2002, carrying Eutelsat 70A to

geostationary transfer orbit In space mission design, a geostationary transfer orbit (GTO) or geosynchronous transfer orbit is a highly elliptical type of geocentric orbit, usually with a perigee as low as low Earth orbit (LEO) and an apogee as high as geostationary orbit ...

. On December 21, 2004, SLC-37 supported the maiden flight of the

, which aimed at carrying a boilerplate and an assortment of small satellites into orbit. The next year, citing issues that sprang up with competition, Boeing announced that Delta operations at the pad and at SLC-17 would be combined with those of

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas (rocket family), Atlas launch vehicle family. It was developed by Lockheed Martin and has been operated by United Launch Alliance (ULA) since 2006. Primarily used to ...

at Space Launch Complex 41 (SLC-41) as part of a

joint venture A joint venture (JV) is a business entity created by two or more parties, generally characterized by shared ownership, shared returns and risks, and shared governance. Companies typically pursue joint ventures for one of four reasons: to acce ...

with

Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...

. This handover would be made official with the establishment of

United Launch Alliance United Launch Alliance, LLC (ULA) is an American launch service provider formed in December 2006 as a joint venture between Lockheed Martin Space and Boeing Defense, Space & Security. The company designs, assembles, sells and launches rockets ...

(ULA) in December 2006, and SLC-37 supported its first launch under ULA with a Delta IV Heavy flight on November 11, 2007. During the Delta IV era, SLC-37 underwent 35 launches of the family, consisting of 29 Medium launches and 16 Heavy launches. Almost all payloads launched were governmental in nature, with a majority of that subsection being military customers such as the Air Force, the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

, and the

National Reconnaissance Office The National Reconnaissance Office (NRO) is a member of the United States Intelligence Community and an agency of the United States Department of Defense which designs, builds, launches, and operates the reconnaissance satellites of the U.S. f ...

. Some notable missions launched from the facility include GOES-N, GOES-O, and GOES-P for

NOAA The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with forecasting weather, monitoring oceanic and atmospheric conditions, charting the seas, conducting deep-sea exploratio ...

throughout the late 2000s,

Exploration Flight Test-1 Exploration Flight Test-1 or EFT-1 (previously known as Orion Flight Test 1 or OFT-1) was a technology demonstration mission and the first flight test of the crew module portion of the Orion spacecraft. Without a crew, it was launched on 5&nb ...

for NASA's Orion spacecraft in 2014, and the

Parker Solar Probe The Parker Solar Probe (PSP; previously Solar Probe, Solar Probe Plus or Solar Probe+) is a NASA space probe launched in 2018 to make observations of the Stellar corona, Sun's outer corona. It used repeated Gravity assist, gravity assists from ...

in 2018. Throughout the late 2010s and early 2020s, ULA began to wind down operations at the complex in preparation for the Delta IV's retirement. Their new launch vehicle to replace the Delta and Atlas families,

Vulcan Centaur Vulcan Centaur is a heavy-lift launch vehicle developed and operated by United Launch Alliance (ULA). It is a two-stage-to-orbit launch vehicle consisting of the Vulcan first stage and the Centaur second stage. Replacing ULA's Atlas V and Del ...

, was planning on having its launch site be at SLC-41 and as such ULA opted to let the SLC-37 lease expire. The final Delta IV Medium launch came on August 22, 2019 carrying a

GPS The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geol ...

satellite for the Air Force, while the last overall launch of the Delta family came with a Delta IV Heavy launch for the NRO on April 9, 2024.

Proposals for Starship (from 2025)

During the lead up to the Delta IV's retirement, the

United States Space Force The United States Space Force (USSF) is the space force branch of the United States Department of Defense. It is one of the six United States Armed Forces, armed forces of the United States and one of the eight uniformed services of the Unite ...

(having taken over the Air Force's jurisdiction at Cape Canaveral) and

started to survey using SLC-37 as a launch site for

, complimenting their launch site at

Starbase The concepts of Space station, space stations and space habitats feature in science fiction. The difference between the two is that habitats are larger and more complex structures intended as permanent homes for substantial populations (though ge ...

and existing plans at KSC's Launch Complex 39A, with the

Federal Aviation Administration The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in t ...

being tasked with creating an

(EIS) as part of procedure. In March 2025, SpaceX announced that they received a limited

for SLC-37, with the draft EIS being released in June following a delay from December 2024. In the report, plans call for the construction of two launch pads with integration towers located on the eastern site of SLC-37, being able to support a potential flight cadence of 76 launches per year. In addition, any preexisting infrastructure from the complex's previous incarnations would get removed, with two catch towers analogous to the Falcon 9 landing zones being built in place. On June 12, the

mobile service structure Launch Complex 39 (LC-39) is a rocket launch site at the John F. Kennedy Space Center on Merritt Island, Florida, Merritt Island in Florida, United States. The site and its collection of facilities were originally built as the Apollo program's ...

and lightning towers for the Delta IV pad were imploded in a controlled demolition. At the current moment, SpaceX does not hold a lease for SLC-37, with any actions made to the pad being done with their right of entry. However, an official announcement is expected to occur following the final study's release in September 2025.

Launch statistics

Rocket configuration

List of launches

Saturn I

All flights operated by

Delta IV

All launches from 2002 to 2006 were operated by

. All launches from 2007 to 2024 were operated by

Photos

File:LC-37.jpg, Map of Launch Complex 37 of the 1960s, with original Mobile Service Structure File:Saturn SA9 launch.jpg, The launch of AS-103 with the Pegasus 1 satellite atop a Saturn I, from LC-37B in 1965 File:Liftoff for a Delta IV Medium+ (4,2) after its launch tower.jpg, The launch of GOES-N atop a

, from SLC-37B in 2006 File:Launch Complex 37.jpg, SLC-37B in 2010, with the Mobile Service Tower

Notes

References

External links

Boeing Delta IV website
{{Merritt Island Cape Canaveral Space Force Station Launch complexes of the United States Space Force Apollo program 1964 establishments in Florida