The Space Shuttle: A First in Spacecraft Reusability – Part I
By Dr. Gary L. Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
This is the first article in a two-part series discussing the impact of the Space Shuttle on reusability in spacecraft design.
The Space Transport System (also known as the Space Shuttle) revolutionized American spaceflight. Its design and development were greenlighted by President Richard Nixon in 1969, with flights beginning in the early 1980s. However, what was truly unique about the Space Shuttle was its reusability, which was designed to allow for rapid refurbishment and re-launching; it was envisioned in the design stages that the Space Shuttle would be capable of launches every few weeks.
While this kind of launch frequency never came to be, the reusability of the Shuttle and some components of the launch equipment allowed for some additional efficiencies in the turn-around process.
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The Space Shuttle launch system was composed of three primary components: the shuttle itself (also called the orbiter), the solid rocket boosters (or SRBs), and the main fuel tank. The components were manufactured in different parts of the country and then assembled on site before each launch.
The Main Tank Contained 500,000 Gallons of Liquid Hydrogen and Liquid Oxygen Fuel
Of the three pieces, only the main tank was not reusable. It held 500,000 gallons of fuel — liquid hydrogen and liquid oxygen — for the shuttle engines. It also served as the primary structure for the vehicle, providing a framework onto which the shuttle and SRBs were bolted. During the design phase, it was originally intended that the main tank would be recoverable after a splashdown in the Atlantic Ocean. But NASA engineers determined that this was not a viable plan and they abandoned it.
Instead, the shuttle carried the main tank to about 70 miles in altitude and then detached it and it fell back to Earth. Most of the tank infrastructure was designed to disintegrate on re-entry, and whatever parts did not would splashdown in the ocean and sink. New main tanks were manufactured at Michoud Assembly Facility in New Orleans and shipped to Cape Canaveral, Florida, for launch assembly.
SRBs Provided the Initial Lift the Shuttle Needed to Reach Orbit
The solid rocket boosters, or SRBs, were one of the reusable components of the Space Shuttle launch system. The boosters provided the initial lift the shuttle needed to reach orbit. They would climb with the shuttle and main tank until about 28 miles in altitude and then detach from the frame and fall back to Earth.
The SRBs deployed parachutes to facilitate a soft landing in the Atlantic. The SRBs would be recovered, disassembled and shipped in segments by specialized rail cars to the ATK manufacturing plant in Utah. Each booster comprised nine individual segments, with a nose cone at the top and an engine cone at the bottom.
Each booster contained about 120 tons of fuel, a mixture of liquefied ammonium perchlorate and aluminum. The mixture was poured into casts for each segment. Once the SRBs were ignited at launch, they could not be turned off. They would cease propulsion only after all of the fuel had been exhausted, so it was critical that the refurbishment process for the SRBs was done with impeccable precision to avoid any problems.
Once the SRB segments were insulated and fueled in Utah, they would be partially assembled and then shipped by special rail cars back to Kennedy Space Center, where they would be stacked and attached to a main tank in preparation for launch. Joining the booster segments involved the use of O-ring seals.
One of these seals failed during the disastrous 1986 STS Challenger launch, which killed all seven astronauts onboard. The leaking combustion caused the failed SRB to burn a hole through the side of the main tank that ignited the hydrogen-oxygen fuel mixture and destroyed the vehicle. This is why quality control and attention to detail was so important. NASA made technical changes to the shuttle and also banned civilians as crew members. The shuttle program resumed flights in 1988.
In the second part of this series, we’ll discuss the most important component of the Space Shuttle vehicle — the orbiter.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.