Space polypropulsion

Abstract

Hybrid space propulsion has been a feature of most space missions. Only the very early rocket propulsion experiments like the V2, employed a single form of propulsion. By the late fifties multi-staging was routine and the Space Shuttle employs three different kinds of fuel and rocket engines. During the development of chemical rockets, other forms of propulsion were being slowly tested, both theoretically and, relatively slowly, in practice. Rail and gas guns, ion engines, “slingshot” gravity assist, nuclear and solar power, tethers, solar sails have all seen some real applications. Yet the earliest type of non-chemical space propulsion to be thought of has never been attempted in space: laser and photon propulsion. The ideas of Eugen Saenger, Georgii Marx, Arthur Kantrowitz, Leik Myrabo, Claude Phipps and Robert Forward remain Earth-bound. In this paper we summarize the various forms of nonchemical propulsion and their results. The authors point out that missions beyond Saturn would benefit from a change of attitude to laser-propulsion as well as consideration of hybrid “polypropulsion” – which is to say using all the rocket “tools” available rather than possibly not the most appropriate. The paper is concluded with three practical examples, two for the next decades and one for the next century; disposal of nuclear waste in space; a grand tour of the Jovian and Saturnian moons – with Huygens or Lunoxod type, landers; and eventually mankind’s greatest space dream: robotic exploration of neighbouring planetary systems.