Back in the 1980’s Skylon a hybrid of the jet engine & a chemical rocket was worked on by the Brits and years later impressed the ESA. Having spent a impressive $92 million to date, they now turn to the public in order to fund the remaining 3.6 billion necessary to complete the engine.
Meanwhile Lockheed Martin & NASA have been working on the VentureStar, their own version of a SSTO (single-stage-to-orbit) space vehicle. By 2001, after dumping more than $1 billion in funds, all work was ceased. But the ideas remain. The temptation is there.
Expendable rockets make sense, or so the party line goes. The advantages are that they can carry a larger cargo, more fuel, there is no wear and tear from repeated use and seeing as rockets have been “the” technology since the sixties, there are no R & D costs.
Then why, now that SpaceX is handling the resupply missions, are they testing (very well I might add) rocket stages that are reusable? SpaceX’s goal is launching vehicles where the various stages will return to the launch platform under power of their own thrusters and be ready for another launch, if necessary, within only a few hours of their return.
Obviously this becomes a cake and eat it too situation! A combination of the multiple stage rocket and the benefits that it offers with the reusability that eliminates all that wasted $$. But then is there a reason not to have a SSTO if there is access to a staged launch through SpaceX? Reaction Engines Limited thinks so.
Reaction Engines Limited, a United Kingdom company, has a concept under development called SABRE (Synergistic Air-Breathing Rocket). It is the continuation or evolution of the Skylon launch vehicle. The technology that was apparently out of reach before is now available.
The SABRE’s picture is reminiscent of Buck Rogers more than Star Trek. But in a technology that mimics a jet, perhaps it is exactly what is needed. Elon Musk recently commented that “If planes were not reusable, very few people would fly.” Certainly making a reusable format (again) has it benefits!