From Apollo to Orion: Space Launch Complex 37

Life sometimes presents us with some interesting coincidences and I stumbled upon one in the weeks leading up to the first test flight of NASA’s Orion spacecraft. Orion is being developed to support crewed missions beyond low Earth orbit for the first time since the Apollo lunar missions.  Orion’s first test flight, EFT-1, was meant to test some of the spacecraft’s systems during a two-orbit mission culminating with a high-speed reentry and recovery in the Pacific Ocean. For this mission, the world’s most capable operational launch vehicle, the Delta IV Heavy, was used from Space Launch Complex 37 (SLC-37) at the Cape Canaveral Air Force Station on Florida’s Atlantic coast. By a strange coincidence of history, the first unmanned orbital test flights of Apollo were also launched from what was then called Launch Complex 37 (LC-37) a half century earlier from the same spot as SLC-37 today.

The Beginning of LC-37

Back in the opening years of the Space Age in the late 1950s, the group of engineers and scientists under the direction of famed German-American rocket pioneer Wernher von Braun (working at what would become NASA’s Marshall Space Flight Center) were already busy designing a family of heavy-lift rockets eventually called Saturn. In 1959, work began at Cape Canaveral to build Launch Complex 34 (LC-34) to support the first test flights of the Saturn C-1 (later known simply as the Saturn I) rocket starting in 1961.

Diagram showing the original layout of LC-37. Click on image to enlarge. (NASA)

Early on it was recognized that a second pad would be required to support the expected higher launch rates of Saturn rockets and serve as a back up in case a pad was lost in a launch accident. Unfortunately, a second pad at LC-34 south of the first proved to be impractical because it would be only 730 meters from LC-20 which was then supporting Titan ICBM testing and launches from a “pad 34B” would overfly LC-20 (see “The First Titan III Launches“). The solution was to build a new, two-pad complex designated LC-37 about 1.2 kilometers to the northwest of LC-34 that would be capable of supporting launches of the Saturn C-1 and even larger C-2 (the Saturn C-2 was a significantly upgraded version of the C-1 being considered in the early 1960s for heavy-lift missions). LC-37 would be about three times the size of LC-34 and cover about a half of a square kilometer – more than large enough to support launches of new heavy-lift rockets at an anticipated rate of up to eight launches per year.

Aerial view of LC-37 in the 1960s with pad B in the foreground and the mobile service structure back near pad A. (NASA)

An invitation for bids for work on LC-37 went out in March 1961 with site preparation starting that April. When it was completed, LC-37 consisted of a pair of launch pads designated A and B that each had their own launch pedestals and 82-meter tall umbilical towers. The two pads used the same blockhouse to support the launch crew as well as propellant facilities, utilities and other infrastructure. Both pads also shared the same 92-meter tall mobile service structure used in the assembly and checkout of the Saturn rockets on their pads. This rail-mounted structure, with a mass of 4,260 metric tons, was the largest wheeled structure in the world at that time.

Wernher von Braun (left next to the SA-5 model) giving President Kennedy a tour of the just-completed LC-37 on November 16, 1963 – just six days before his assassination. (NASA)

Work on both pads was completed in August 1963 and NASA immediately started work at pad B to prepare for the launch of SA-5 (see “The Coolest Rocket Ever”). SA-5 was the fifth in the series of Saturn I test flights that had been earlier using LC-34. The launch of SA-5 from LC-37 would be the first flight of the Block II model of the Saturn I that used a live hydrogen-fueled second stage, designated the S-IV, to launch a payload into Earth orbit. In addition to being the first orbital flight of the Saturn program, it was only the third time that a hydrogen-fueled upper stage had been flown at that time (the previous flights being a pair of Atlas-Centaur test flights from LC-36 the first of which had failed in 1962). SA-5 lifted off on January 29, 1964 and successfully placed its empty second stage and payload of ballast in Earth orbit. With an orbital mass of 17.6 metric tons, this was the heaviest object ever placed into Earth orbit at that time and finally gave the US an edge in launch capability over the Soviet Union (see “The Largest Launch Vehicles Through History“).

SA-5 sitting on pad B at LC-37 before its launch in January 1964. Note the rail-mounted mobile service structure back and to the left of pad B with the tower at pad A just visible behind SA-5. (NASA)

With this first launch under its belt, NASA shifted operations at LC-37 towards an increasing pace of Saturn I flights that would now be used in the initial orbital test flights of Apollo hardware. The first of these Apollo flights was called A-101 and used the Saturn I designated SA-6. The objectives of these first test flights was a demonstration of the compatibility of the Apollo spacecraft and Saturn launch vehicle, verification of the aerodynamic properties of the Apollo spacecraft and a demonstration of the jettisoning of the Apollo launch escape system (LES) under realistic ascent conditions. To meet these goals, boilerplate models of the Apollo were employed. Boilerplate models reproduce the mass, shape and dynamic properties of flight models but otherwise only carry systems and instruments needed for the tests being conducted.  Their low costs and adaptability make them ideal for early testing of a new spacecraft design. The first Apollo test flight lifted off from pad 37B on May 28, 1964 and successfully placed Apollo BP-13 into a low Earth orbit that simulated the parking orbits to be used by future Apollo lunar missions (see “The First Apollo Orbital Test Flight”).

The first Apollo orbital test flight, A-101, on pad B at LC-37 before its launch in May 1964. (NASA)

The next Apollo test flight, A-102, repeated the feat with SA-7 on September 18, 1964 (see “The Second Apollo Orbital Test Flight”). The A-103 flight, launched using SA-9 on February 16, 1965, was the first Saturn launch to carry a working payload into orbit. Tucked inside the Apollo boilerplate BP-16 was the first Pegasus satellite which deployed large panels to detect micrometeoroid impacts in Earth orbit (see “The Mission of Apollo A-103/Pegasus 1“). The Apollo A-104 flight using SA-8 launched the second Pegasus satellite housed inside of an Apollo boilerplate model on May 25, 1965 for the only night launch of the Saturn I program (see “The First Apollo-Saturn Night Launch”). The final Saturn I flight, SA-10, launched the last Pegasus satellite as part of the Apollo A-105 test flight on July 30, 1965 (see “The Last Launch of the Saturn I“). Because of the low launch rate, all six Saturn I flights from LC-37 used pad B.

The End of LC-37

This last flight of the Saturn I came just before a July 31, 1965 deadline to cease launches from LC-37 so that work could begin upgrading the facilities to support flights of the new Saturn IB. The Saturn IB used an upgraded Saturn I first stage and a new, larger second stage designated the S-IVB that also served as the third stage of the Saturn V that was to be used to launch Apollo to the Moon. The upgraded Saturn IB would be used to launch Apollo hardware into Earth orbit from LC-37 and a refurbished LC-34 as well as provide flight experience with the new S-IVB stage.

A night view of Apollo AS-203 on pad B at LC-37 before its launch in July 1966. This mission sent the Saturn IB S-IVB stage into orbit without a payload in order to observe the behavior of the liquid hydrogen in its tank. (NASA)

The first launch of the Saturn IB from the modified LC-37 came on July 5, 1966 (less than a year after the last Saturn I launch). This flight, designated AS-203, was the second flight of the Saturn IB but, unlike the first which carried the first Apollo flight model on a suborbital test, this flight would carry no spacecraft. The objective of this mission was to observe the behavior of liquid hydrogen in the S-IVB-200 fuel tank in low Earth orbit. The Saturn V would use a S-IVB-500 model of this stage which would have to coast in parking orbit for a time before reigniting to send the Apollo to the Moon. Verification of the performance of the anti-slosh baffles and other design features inside the fuel tank was desirable to help mitigate risks during the upcoming Saturn V test flights. For this mission, Saturn SA-203 was topped by a simple nosecone and carried a light load of liquid oxygen in the S-IVB stage to ensure enough liquid hydrogen remained in the tank for testing during its brief two-orbit mission (see “AS-203: NASA’s Odd Apollo Mission“).

What would turn out to be the final mission from LC-37 (at least in its initial incarnation) was the Apollo 5 mission launched on January 22, 1968 (see “Apollo 5: The First Flight of the Lunar Module“). For this unmanned Apollo flight, Saturn SA-204 lifted the Apollo Lunar Module, LM-1, into low Earth orbit for the first test flight of this vital piece of Apollo hardware. The mission objectives were successfully met after eight hours hours in orbit and the now deactivated stages of the LM were allowed to decay out of orbit during the days that followed. The next Apollo-Saturn IB mission, the manned Apollo 7 Earth orbital flight, would use LC-34. All subsequent Apollo (and later, Skylab) missions using the Saturn V and IB would be launched from LC-39.

A view of Apollo 5 on pad B of LC-37. It carried the first Apollo LM into orbit for an unmanned test flight in January 1968. This would be the last flight from this site for almost 35 years. (NASA)

With the launch of Apollo 5, the initial career of LC-37 had come to an early end. The high launch rates for Saturn I and other heavy lift rockets originally anticipated when LC-37 was constructed never materialized (in fact, pad 37A was never even used) and there simply was no future need foreseen for these facilities. NASA officially deactivated LC-37 on January 1, 1969 and mothballed the facility in November 1971. The mobile service tower was scrapped in April 1972 and LC-37 was officially returned to USAF control in November 1973. A launch complex originally built with such high hopes was now gone only a decade after it had been officially accepted by NASA.

The Birth of SLC-37

After the retirement of the Saturn family in the early 1970s, American heavy lift requirements were met by the Titan III and IV as well as by the Space Shuttle. But eventually these systems would be retired with new launch vehicles taking their place such as the Boeing/United Launch Alliance (ULA) Delta IV family of launch vehicles. When Boeing began looking for an east coast launch site for their new EELV (Evolved Expendable Launch Vehicle) program in the late 1990s, the old site of LC-37 proved to be an excellent option. At the beginning of 1998, Boeing received a “Right of Entry” to begin work rebuilding what would now be called Space Launch Complex 37 (SLC-37). By the end of 2000, a new 100-meter tall mobile service tower and the Horizontal Integration Facility (HIF) were completed to support operations on pad 37B which now sports new fixed umbilical and lightning protection towers to support launches of all Delta IV configurations.

Diagram showing the current facilities at SLC-37 with a Delta IV Heavy on the pad. Click on image to enlarge. (ULA)

The first launch from the new SLC-37 occurred on November 20, 2002 – almost 35 years after the launch of Apollo 5. This first flight employed the Delta IV Medium+(4,2) (serial number 293 consisting of a Common Booster Core or CBC, a second stage and a pair of solid rocket boosters) to launch the Eutelsat W5 communications satellite successfully into a geosynchronous transfer orbit. The first launch from SLC-37B of a Delta IV Heavy (which uses a pair of CBCs as boosters and has a third again the orbital payload capacity of the old Saturn IB) occurred on December 21, 2004. The early shutdown of all three CBCs as a result of propellant sensor issues on Delta IV serial number 310 resulted in a performance shortfall and a “partial failure” of the mission since the test payloads failed to reach orbit. These early issues were corrected and subsequent flights of all Delta IV models from SLC-37 and the west coast have been successful.

A Delta IV Medium(+4,2) carrying the GOES-O geosynchronous weather satellite on the pad at SLC-37 before its launch in June 2009. (ULA)

SLC-37 continues to support a steady stream of Delta IV launches of various military and civilian payloads into orbit for over a dozen years now (longer than its earlier career supporting the Saturn program). The Orion EFT-1 test flight from SLC-37 represents the 30^th flight from this location in the past half a century. It seems only appropriate that the first test flight of Orion which will eventually support crews in flights beyond low Earth orbit is being flown from the same launch pad that supported the first orbital test flights of Apollo at the beginning of the Space Age.

Follow Drew Ex Machina on Facebook.

Related Reading

“The Coolest Rocket Ever”, Drew Ex Machina, March 30, 2014 [Post]

“The First Apollo Orbital Test Flight”, Drew Ex Machina, May 28, 2014 [Post]

“The Second Apollo Orbital Test Flight”, Drew Ex Machina, September 18, 2014 [Post]

“The Launch of Apollo A-103/Pegasus 1”, Drew Ex Machina, February 16, 2015 [Post]

“The First Apollo-Saturn Night Launch”, Drew Ex Machina, May 25, 2015 [Post]

“The Last Launch of the Saturn I”, Drew Ex Machina, July 30, 2015 [Post]

“AS-203: NASA’s Odd Apollo Mission”, Drew Ex Machina, July 5, 2016 [Post]

“Apollo 5: The First Flight of the Lunar Module”, Drew Ex Machina, January 22, 2018 [Post]

General References

David S. Akens, Saturn Illustrated Chronology, Saturn’s First Eleven Years: April 1957 to April 1968 (MHR-5), NASA Marshall Space Flight Center, January 20, 1971

Charles D. Benson and William B. Fahery, Gateway to the Moon: Building the Kennedy Space Center Launch Complex, University Press of Florida, 2001

Roger E. Bilstein, Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles, University Press of Florida, 2003

Launch Complex 37, Air Force Space & Missile Museum web site [Web site]