page_title: Space Shuttle design process
hierarchical_section_title: Space Shuttle design process
caption_attribution_description: Space Shuttle Concepts illustration showing late 1960's designs, part of the Phase A-prime process. The baseline design at the bottom represents a composite of features from different individual designs that met the Manned Spacecraft Center's (MSC) basic requirements spec. All of these were based on a two-stage design, with both stages manned and capable of a horizontal landing. This design had evolved out of a series of evolutionary studies during the Phase A process, and NASA planners became concerned that the resulting designs were too focused on the two-stage concept. So as part of an A' series, they asked for more radical solutions. Some of the results are shown as the upper five concepts in this image. The two designs directly above the baseline concept were variations on the basic concept; on the right the fly-back booster has been replaced by two large booster rockets running down the side of the fuselage, while on the left the orbiter has been replaced by a conventional disposable rocket on top of the baseline booster. In the middle-right is the North American DC-3 concept developed by Maxime Faget's team at the Marshall Space Flight Center (MSFC). This was largely a replacement of the MSC's delta-wing design with straight wings, which offered better performance and far more flexibility to change the position of the wing in the case of the almost unavoidable changes in center of gravity. In spite of never being a serious contender for the Shuttle program, the team was able to secure considerable funding, developing free-flight models and creating extensive design materials which were found in publications well into the 1970s. At the top are the two most radical concepts, the Lockheed Star Clipper on the right and the Chrysler SERV on the left. The Star Clipper (and the somewhat similar McDonnell Douglas proposal, Tip Tank) were stage-and-a-half designs using a single powered orbiter combined with disposable drop tanks. SERV was the most radical design by far, a single-stage-to-orbit (SSTO) vehicle using an advanced engine design capable of completely automated missions. In this illustration SERV is shown with a fly-back shuttle on top, the MURP. The various designs are not shown to scale. DC-3 is somewhat larger than the baseline design, and SERV is larger than any of them - the MURP was roughly the size of the DC-3 orbiter, which provides some sense of scale. Forces outside of NASA's control led to dramatic changes to the program scope. These designs were intended to launch a maximum of 35,000 lbs eastward from Kennedy, which would limit their polar capability to perhaps 20,000 lbs. In order to ensure funding, NASA asked the Air Force to join the program and cancel their own Titan IIIN design. However, IIIN had been designed specifically to launch spy satellites as large as 40,000 lbs into polar orbit, the equivalent of launching 65,000 lbs east from Kennedy. None of the Phase B designs could be scaled to this size without enormous increases in price, and this led to the semi-reusable design that eventually went into service.
context_page_description: Before the Project Apollo Moon landing in 1969, NASA began studies of Space Shuttle designs as early as October 1968. The early studies were denoted "Phase A", and in June 1970, "Phase B", which were more detailed and specific. The primary intended use of the Space Shuttle was supporting the future space station, ferrying a minimum crew of four and about 20,000 pounds of cargo, and able to be rapidly turned around for future flights.
  Two designs emerged as front-runners. One was designed by engineers at the Manned Spaceflight Center, and championed especially by George Mueller. This was a two-stage system with delta-winged spacecraft, and generally complex. An attempt to re-simplify was made in the form of the DC-3, designed by Maxime Faget, who had designed the Mercury capsule among other vehicles. Numerous offerings from a variety of commercial companies were also offered, but generally fell by the wayside as each NASA lab pushed for its own version.
  All of this was taking place in the midst of other NASA teams proposing a wide variety of post-Apollo missions, a number of which would cost as much as Apollo or more.
context_section_description: Before the Project Apollo Moon landing in 1969, NASA began studies of Space Shuttle designs as early as October 1968. The early studies were denoted "Phase A", and in June 1970, "Phase B", which were more detailed and specific. The primary intended use of the Space Shuttle was supporting the future space station, ferrying a minimum crew of four and about 20,000 pounds (9,100 kg) of cargo, and able to be rapidly turned around for future flights.
  Two designs emerged as front-runners. One was designed by engineers at the Manned Spaceflight Center, and championed especially  by George Mueller. This was a two-stage system with delta-winged spacecraft, and generally complex. An attempt to re-simplify was made in the form of the DC-3, designed by Maxime Faget, who had designed the Mercury capsule among other vehicles. Numerous offerings from a variety of commercial companies were also offered, but generally fell by the wayside as each NASA lab pushed for its own version.
  All of this was taking place in the midst of other NASA teams proposing a wide variety of post-Apollo missions, a number of which would cost as much as Apollo or more. As each of these projects fought for funding, the NASA budget was at the same time being severely constrained. Three were eventually presented to Vice President Agnew in 1969. The shuttle project rose to the top, largely due to tireless campaigning by its supporters. By 1970 the shuttle had been selected as the one major project for the short-term post-Apollo time frame.
  When funding for the program came into question, there were concerns that the project might be cancelled. This led to an effort to interest the US Air Force in using the shuttle for their missions as well. The Air Force was mildly interested, but demanded a much larger vehicle, far larger than the original concepts. To lower the development costs of the resulting designs, boosters were added, a throw-away fuel tank was adopted, and many other changes made that greatly lowered the reusability and greatly added to vehicle and operational costs. With the Air Force's assistance, the system emerged in its operational form.
caption: Early U.S. space shuttle concepts
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