Assessment of the Feasibility of Innovative Reusable Launchers
Abstract
The demand for getting access to space, in particular to Low Earth Orbit, is increasing and fully reusable launch vehicles (RLVs) are likely to play a key role in the development of future space activities. Up until now this kind of space systems has not been successfully carried out: in fact today only the Space Shuttle, which belongs to the old generation of launchers, is operative and furthermore it is not a fully reusable system. In the nineties many studies regarding advanced transatmospheric planes were started, but no one was accomplished because of the technological problems encountered and the high financial resources required with the corresponding industrial risk. One of the most promising project was the Lockheed Venture Star, which seemed to have serious chances to be carried out. Anyway, if this ever happens, it will take quite a long time thus the operative life of Space Shuttle will have to be extended for the International Space Station support. The purpose of the present work is to assess the feasibility of different kinds of advanced reusable launch vehicles to gain access to space and to meet the requirements of today space flight needs, which are mainly safety and affordability. Single stage to orbit (SSTO), two stage to orbit (TSTO) and the so called "one and a half" stage to orbit vehicles are here taken into account to highlight their advantages and disadvantages. The "one and a half" stage to orbit vehicle takes off and climbs to meet a tanker aircraft to be aerially refuelled and then, after disconnecting from the tanker, it flies to reach the orbit. In this case, apart from the space vehicle, also the tanker aircraft needs a dedicated study to examine the problems related to the refuelling at high subsonic speeds and at a height near the tropopause. Only winged vehicles which take off and land horizontally are considered but different architectural layouts and propulsive configurations are hypothesised. Unlike the Venture Star, which takes off like the Space Shuttle, this kind of reusable launch vehicles, called spaceplanes, should all be able to be maintained and operated from airports, thus making the launch and recovery phases easier and more affordable. Apart from being an innovative attempt to get access to space, spaceplanes look likely to revolutionize long distance plane travel, with travel times between any two cities connecting USA, Europe, Japan and Australia being only a few hours. SSTO winged vehicles may be at the margins of feasibility as a reusable SSTO design attempts to take two major steps at once: step one being a fully reusable vehicle and step two being a single-stage reusable vehicle. It is well known that the accomplishment of the SSTO vehicle requires a dramatic effort from the technological point of view even though the integration design appears to be quite easy. If compared to the SSTO, the TSTO reusable vehicle is less technically demanding as, for example, state-of-the-art engines can be used but the integration design is surely more complex. An optimum solution may be represented by the "one and a half" stage to orbit vehicle. In fact getting the "one and a half" reusable vehicle into orbit doesn't look impossible but it surely does look challenging. In this paper the study of the feasibility and the technological assessment of new space systems concepts are accomplished by: The work we are involved in is still under way but the first results we have had are encouraging.
- Publication:
-
IAF abstracts, 34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002iaf..confE.976C