The space shuttle was supposed to answer all of America's space launch needs, commercial, military, and NASA. Despite many accomplishments, the shuttle failed to lower the cost of space travel and, with two shuttle accidents, increase its safety and reliablity. Real solutions to the problem of cheap and reliable space travel, after a long time in coming, seem to be at hand.
The Prehistory of Winged Rockets
The first important study of winged rockets came from Eugen
Sanger, a specialist in aeronautics and propulsion who received a doctorate at
the Technische Hochschule in Vienna and stayed on to pursue research on
rocket engines. During World War II, Sanger showed how the addition of wings to
a rocket could greatly extend its range. Initially, a winged rocket would fly
to modest range, along an arcing trajectory like that of an artillery shell.
Upon reentering the atmosphere, however, the lift generated by the rocket's
wings would carry it upward, causing it to skip off the atmosphere like a flat
stone skipping over water. Sanger calculated that with a launch speed
considerably less than orbital velocity, such a craft could circle the globe
and return to its launch site.
Reusable rockets with wings were depicted in a series of
articles on the future of space flight in Colliers Magazine in the early 1950s.
The concept was further popularized in the movie Conquest of Space in 1953,
which depicted not only a winged, reusable rocket, but a wheel shaped space
station and an expedition to Mars.
The X 15, which flew in the early 1960s, was an experimental
winged rocket that tested many of the technologies and flying techniques that would
later be used in the space shuttle. The X-15 repeatedly flew a trajectory that
significantly resembled flight to orbit and return. The X-15 ascended into
space under rocket power, flew in weightlessness, and then re-entered the
atmosphere at hypersonic speeds. With its nose high to reduce overheating and
aerodynamic stress, the X-15 used thermal protection to guard the craft against
the heat of reentry. After reentry, the X-15 then maintained a stable attitude
throughout its deceleration, transitioned to guiding flight, and landed at a
preselected location. The shuttle would do all these things, albeit at higher
speeds.
The Air Force started the first serious winged reusable
rocket project, known as Dyna Soar. Dyna Soar would have been lofted a single pilot
on a Titan 3-C rocket for orbital flights. The project, however, was canceled
by then Secretary of Defense Robert McNamara for lack of a clear, military
mission.