From Apollo to multi-user, the changing yet similar nature of Launch Complex 39

by Ryan Weber

As the Artemis 1 SLS vehicle prepares to take its place on LC-39B later this year for its first round of pad testing ahead of its debut mission, the Space Launch System (SLS) and Artemis program represent yet another major alteration to the LC-39 area of the Kennedy Space Center, originally designed to meet President Kennedy’s goal of landing a man on the Moon by the end of the 1960s.

Since Apollo, complex 39 has transformed itself to suit the needs of a changing space program, going on to serve space station operations, the meeting of the Soviet Union and the United States in space, the deployment of numerous international commercial and government satellites, missions with civilian crewmembers, space telescope launches, station assembly and maintenance missions, and a multi-user expansion in the 2010s.

How it began

On May 25, 1961, President Kennedy challenged NASA to put a man on the Moon by the end of the decade, a charge that fueled the Apollo program and the major infrastructure it would need.  Specifically, the challenge would require a massive expansion of NASA operations at Cape Canaveral, and in 1962, the Launch Operations Center’s site was chosen on Merritt Island, adjoining the Cape to the west and north.

At the time, the highest-numbered launch site at the Cape Canaveral Air Force Station (now Cape Canaveral Space Force Station) was Launch Complex 37.  When the Apollo launch site was designed, it was therefore designated Launch Complex 39, with the initial design calling for five launch pads, A through E.  

Ultimately, only two were built: LC-39A and LC-39B.  During the initial design of the LC-39 area, the current pad 39A was to be 39C while 39A would have been farther north near the proposed pads 39D and 39E.  The crawlerway to 39B belies the fact that additional pads were planned given a small extension toward their proposed locations was built.

The original plan for LC-39. (Credit: NASA)

Due to budgetary reasons, only two pads were constructed, becoming the LC-39A and 39B known today.

Decisions that shaped the complex

Shortly after acquiring the site for the new launch complex, NASA was faced with several decisions that still impact programs using the site today.

First, assembly of the gigantic rockets would take place not at the launch pads but inside a large Vehicle Assembly Building (VAB) located at least 5 km away.  This would necessitate the need to stack the rockets on mobile launch platforms and then transport the fully assembled launcher/stand to the pads.

Some of the options considered for this type of transportation were railway, barge, and crawler.  The crawler option was the cheapest and easiest of the three — thus leading to the wrapping river rock-covered crawlerway around the VAB and out to the two pads.

In order to move the fully assembled Saturn V to the pad, specially-built crawlers were needed, and NASA contracted for the development and build of two transporter vehicles, each with a mass of 2,721 metric tons.

The crawlers would be like no vehicle before them, with a need to not just transport the Saturn V and its mobile tower stack up to 7 kilometers, but also be able to keep the combo level (within 30 cm of perfectly level) as they climbed the five degree incline up to the pad surface.

Far too large and massive to be built elsewhere and shipped in, both crawlers were assembled on-site at the LC-39 complex.  Built by Marion Power Shovel Company with assistance from Rockwell International, the crawlers remain the largest self-powered land vehicles in the world with a length of 40 m, a width of 35 m, and an adjustable height of 6.1 to 7.9 m with independent jacking and leveling systems on each track.

They are propelled by eight tracks, with each track consisting of 57 shoes — each of which has a mass of 900 kg. As a result, they can attain a maximum unloaded speed of 3.2 km/h and a maximum loaded speed of 1.6 km/h.

Incapable of turning around, each crawler is outfitted with two cabs, one at either end.  To “reverse” down the crawlerway, operators switch to the forward (direction of travel) cab and drive the crawler forward from there.

Nicknamed Hanz and Franz, the two crawlers were added to the National Register of Historic Places on January 21, 2000 — ensuring their preservation.

Designed solely to transport the Saturn V rockets, mobile servicing structures, and mobile launch platforms to and from the pads, the crawlers needed a road — or rather, a crawlerway — to drive on.

This double-track path needed to be able to handle the mass of the transporter and the Saturn V on top.  The crawlerway itself has a width of 40 meters, consisting of two 12 m lanes and a 15 m grassy median, and has a depth of 2 meters, which includes 10 cm of Alabama river rock on top of 1.2 m of graded, crushed stone, which is itself on top of two layers of fill.

The crawlerway leads from the Vehicle Assembly Building to either pad 39A or 39B.  The two pads were built with 52,000 cubic meters of concrete to handle the power of the Saturn V first stage, a large, level surface for the rocket and mobile launch platform to sit atop, as well as connections to pad equipment and fueling lines.

The rocket would sit over a large flame trench, which measured 13 meters deep, 18 meters wide, and 137 meters long.  Each trench had two sets of flame deflectors so one could be used while the other was refurbished. Each deflector measured 12 meters high by 15 meters wide by 23 meters long and carried a mass of 635 metric tons.

Each pad was built with two large spheres for holding liquid oxygen and liquid hydrogen for fueling the Saturn V and with a blast-resistant Rubber Room located 12 m underground with evacuation tunnels leading to them.  Each rubber room could support 20 people for 24 hours.

NASA astronaut Wendy Lawrence examines a seat in the rubber room. (Credit: NASA)

Additionally, a Launch Control Center (LCC) was also needed to test the rockets in the VAB and to control and conduct countdown and launch operations at LC-39A and 39B.

For the VAB, NASA needed a building capable of preparing multiple vehicles at the same time to meet the challenge set forth by President Kennedy. As a result, the VAB was and still is the largest single story building in the world at 218 meters by 158 meters by 160 meters, with an internal volume of 3,665,000 cubic meters.

The building included four high bays capable of stacking and/or preparing Saturn V rocket stages for assembly and launch, with each high bay supporting a single rocket build-up at a time.  Ultimately, only High Bays 1, 2 and 3 were used for stacking operations.

To assemble and launch the Saturn V, three Mobile Launcher (MLs), each with a mass of 5,715 metric tons, were constructed with the Saturn V’s Launch Umbilical Tower on them.

The Apollo era

Once a Saturn V was at the pad, workers would lose access to most of the rocket due to its exposed nature and distance from its launch tower.  In order to service the rocket on the pad, NASA built the Mobile Service Structure that the crawlers would move into position.

To coordinate and launch the Saturn V,  the LCC’s 2nd floor accommodated telemetry, instrumentation, RF and tracking, and evaluation while the 3rd floor contained the four Firing Rooms, one for each of the high bays in the VAB — with each active room housing 470 sets of control and monitoring equipment.

The first mission to use Launch Complex 39 was Apollo 4.  Launched from LC-39A on November 9, 1967 at 12:00:01 UTC, the first full test flight of the Saturn V lifted into space.  A second test flight, Apollo 6, followed before the first crewed flight from the human spaceport occurred with Apollo 8 on December 21, 1968 — the first flight in history to send humans to another celestial body.  

Apollo Skylab rolls out of VAB HB2 on 16 April 1973. (Credit: NASA)

The most-watched and most famous mission to ever launch from Complex 39 came on July 16, 1969 when Neil Armstrong, Buzz Aldrin, and Micheal Collins lifted off from Pad 39A on the Apollo 11 mission to fulfill — with five months to spare — President Kennedy’s goal.

The final Saturn V launch from LC-39 took place from Pad-A on May 14, 1973 when a modified version of the rocket lofted Skylab into low Earth orbit.

All told, 12 of the 13 Saturn Vs launched lifted off from 39A, with Apollo 10 marking the only use of 39B for a Saturn V.  Following their final uses for Saturn V, some of the launch platforms were modified with a milk-stool to launch Apollo capsules on Saturn 1B rockets for the Skylab crew missions as well as Apollo-Soyuz, the final Apollo-era launch on July 15, 1975.

Space Shuttle era

While Apollo was ongoing, NASA was directed to develop a new system, a reusable rocket to follow the Saturn V.  Instead of building completely new facilities, NASA took what was built for Apollo and reconfigured it and altered it to suit the needs of the new vehicle: the Space Shuttle.

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