Throughout the early decades of space exploration, there were no reusable launch vehicles, and so each launch was extremely expensive. NASA's plans for a Space Shuttle, developed in the early 1970s under the administration of James C. Fletcher and announced by President Nixon on 5 January 1972, were supposed to drastically cut the costs of reaching orbit, and make routine spaceflight a reality.
With budget and political backing secured, NASA invited concepts from contractors and was deluged with a huge variety of concepts. The most popular early plan envisaged a two-stage vehicle, with the spaceplane carried most of the way to orbit by a large rocket-powered, piloted carrier aircraft - a larger equivalent of the X-15 system. When this concept was abandoned as too costly, NASA reluctantly recognized that not all of the system, now known formally as the Space Transportation System (STS), could be completely reusable.
The basic idea of a winged, rocket-powered space vehicle that can use aerodynamic lift to travel at least part of the way into space was first proposed in the 1930s by Eugen Sanger, a member of the German VfR rocket society. His concept involved an aircraft launched at supersonic speeds on a rocket-powered sled (see p.298). Other ideas often used some combination of a ballistic launch and a planelike descent, such as the British MUSTARD concept (see panel, below).
The true ancestors of the Space Shuttle, however, were the hypersonic X-craft. Close relations of the Bell X-1 (see p.34), these craft could fly at more than five times the speed of sound and were tested by NACA and NASA throughout the 1950s and 1960s. Several of the later designs had stubby wings and relied on the shape of the fuselage itself to generate most of their aerodynamic lift - they are often referred to as lifting bodies. Normally carried to high altitude while attached to a larger aircraft, they fired their rocket engines on release, accelerating rapidly and following trajectories that looped up to 28km (17 miles) above the Earth, before plummeting back in a hair-raising unpowered, supersonic glide. Although NASA did not pursue the lifting body concept at the time, it has proved highly influential in plans for the next generation of spaceplanes (see p.298).
Another type of X-craft was typified by the X-15, a rocket-powered research plane piloted by Neil Armstrong and Scott Crossfield (see panel, opposite)
24 October 1968
The X-15 makes its 199th and final flight.
17 April 1969
The X-24A, prototype of a lifting body plannned by the USAF for potential launch on a Titan rocket, makes its first test flight.
President Nixon announces that NASA's next major space project will be the development of a winged reusable launch vehicle - the Space Shuttle. Shortly afterwards, USAF signs up as a partner in the Shuttle programme, and eventually abandons its research into rocket-launched lifting bodies.
The Soviet Spiral was an orbiter to be launched from a hypersonic aircraft. It was abandoned in 1971.
The X-15 was 15m (50ft) long, with a wingspan of just 6.7 m (22ft). Rear rockets powered it to a height of 108km (67 miles) and speeds of up to Mach 6.7.
Albert Scott Crossfield (1921-2006) was widely viewed as America's top test pilot - the man who often took experimental aircraft like the X-15 into the sky for the first time. After serving as a pilot and flight instructor during the Second World War, he joined NACA in 1950 but left to work for North American Aviation in 1955. In the late 1950s, he and several of his colleagues were briefly considered as pilots for a manned spaceflight.
SPACE SHUTTLE LAUNCH AND RETURN
SPACE SHUTTLE LAUNCH AND RETURN
Was this article helpful?