Before the first Space Shuttle reached orbit in 1981, NASA had been working on its design for almost two decades.
Walter Dornberger, a former German V-2 rocket scientist, drew up the first proposal for a spaceplane in 1954 for what was then called the National Advisory Committee for Aeronautics (NACA). That led to the construction of the North American X-15, a rocket-powered aircraft that would be dropped from a larger aircraft. It reached the edge of space with a speed of Mach 6.7 in 1967, still the world record for the highest speed ever recorded by a crewed aircraft.
Boeing X-20
Not too dissimilar from the X-15, the Boeing X-20 Dyna-Soar (short for “Dynamic Soarer”, and, yes, that’s seriously what they called it) was designed for both civilian and military space use: repairing satellites one day, bombing the Soviets the next. The project kicked off in 1957. Neil Armstrong was secretly selected in 1960 to fly the first Dyna-Soar.
It was not to be. Competition between the Air Force and what had been rebranded the National Aeronautics and Space Administration (NASA), including disagreements over who should carry out manned spaceflights and which rockets to use, doomed the project.
Lockheed Orbital Carrier
Around the same NASA’s own engineers were working on the X-20, Lockheed came up with this reusable orbital carrier. The orbiter itself would have been launched on a booster rocketplane.
ROMBUS
Philip Bono of Douglas Aircraft, a pioneer in the field of reusable launch vehicles, proposed the Reusable Orbital Module-Booster and Utility Shuttle, or ROMBUS, in 1964 for missions to the Moon. His initial version jettisoned the eight hydrogen fuel tanks, but a later plan recytcled the tanks as Moon habitats.
Pegasus and Ithacus were iterations of more or less the same design, including for Mars missions and sea-based launches.
Lockheed Star Clipper
Lockheed’s Star Clipper, proposed by Max Hunter in 1966, had an usual wrap-around drop tank that would be jettisoned in orbit. The idea was that it could launch from and land at regular airports. It would only require a custom-built launchpad.
North American DC-3
One of the first serious designs for what would become the Space Shuttle was the North American DC-3. The name is a little deceptive; it was really an internal NASA study that North American Aviation put their name on.
At the time, NASA was riding high on the success of the Apollo Moon missions and was planning to put a space station in orbit by 1975 and send men to Mars in the 1980s. A spaceplane would come in handy for all those plans.
The DC-3 captured the essential idea of the Space Shuttle: a reusable launch vehicle propelled into orbit by a big rocket.
Star-Raker
At the height of the oil crises of the 1970s, the United States considered launching sixty solar power stations into orbit, which would beam down their energy to Earth. Rockwell International, which sold to Boeing in 1996, proposed the Star-Raker for the task. Powered by ten supersonic ramjet engines, it would jet to an altitude of 29 kilometers at Mach 6 before its rockets kicked in to propel the spaceplane into orbit.
Orbiter on a Booster
In 1971, NASA awarded both North American Rockwell and McDonnell Douglas production contracts for a space shuttle. The thinking at the time was that the space “Orbiter” would be virtually launched on top of a “Booster”, with both being reusable.
Matters were complicated by the Air Force, whose co-financing NASA needed to build the shuttle. They demanded a minimum payload capacity of 65,000 pounds (or 30,000 kilograms, about the weight of a regular bulldozer) in order to carry sophisticated military satellites into orbit. That was nearly three times the weight NASA had in mind!
A cost advantage of building a heavier shuttle, though, was that NASA could carry multiple commercial satellites or parts for a planned space station into orbit with each flight.
In order to accommodate the new requirements, Rockwell and McDonnell Douglas scrapped the planned Booster plane. A modified Saturn V rocket, attached to a large external fuel tank, would be used instead to propel the Orbiter into space.
Enterprise
By 1972, the firms Grumman and Lockheed had also submitted bids to build the Space Shuttle. Rockwell won the contract. Construction of the first shuttle, Enterprise, began in 1974.
Shuttle-Centaur
A side project for the Space Shuttle, developed by General Dynamics, was the Shuttle-Centaur. This envisioned the use of the Space Shuttle to carry a more powerful version of the Centaur rocket into space, from where it could be used to launch probes to Jupiter and Venus. It was canceled after the Challenger disaster in 1986.
