Single-stage to orbit: Encyclopedia II - Single-stage to orbit - Examples

Single-stage to orbit - Examples

Early versions of the Atlas rocket can be considered to be expendable SSTOs by some definitions. It is a "stage and a half" rocket, jettisoning two of its three engines during ascent but retaining its fuel tanks and other structural elements. However, by modern standards the engines ran at low pressure and thus not particularly high specific impulse and were not especially lightweight; using engines operating with a higher specific impulse would have obviated the need to drop engines in the first place.

The first stage of the Titan II had the mass ratio required for single stage to orbit capability with a small payload. A rocket stage is not a complete launch vehicle but this demonstrates that an expendable SSTO was probably achievable with 1962 technology.

The Orion project was potentially single stage to Mars (and back!); but this failed due to health concerns over nuclear fallout.

A detailed study into SSTO vehicles was prepared by Chrysler Corporation's Space Division in 1970-1971 under NASA contract NAS8-26341. Their proposal was an enormous vehicle with more than 50,000 kg of payload, utilizing jet engines for (vertical) landing. While the technical problems seemed to be solvable, NASA preferred a winged design that led to the Shuttle as we know it today.

The unmanned DC-X technology demonstrator, originally developed by McDonnell Douglas for the Strategic Defense Initiative (SDI) program office was an attempt to build a vehicle that could lead to a SSTO vehicle. The 1/3 size test craft was operated and maintained by a tiny crew of three people based out of a trailer, and the craft was once relaunched less than 24 hours after landing. Although the test program was not without mishap (including a minor explosion), the DC-X demonstrated without any doubt that the maintenance aspects of the concept were indeed sound. However, that project ran into repeateded cost overruns, and was eventually cancelled.

Today there is almost no SSTO research in the United States, much to the chagrin of those involved.

There are, a number of efforts around the world to study SSTO, and several have recently progressed to active funding. Primary among these are the Japanese Kankoh-maru project and recent work in Europe on behalf of the ESA on projects like Skylon.

Adapted from the Wikipedia article "Examples", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki