er carrying sub-orbital 2-stage spaceplane being offered by Vela Technology Development and the basis of the ticket deposit scheme being offered by Zegrahm Space Voyages, intended to operate from and return to a commercial airport with a flight time of the order of 2½-3 hours. The booster stage, Sky Lifter, carries the second stage Space Cruiser underneath it on a pylon on twin turbojet engines. After separation, the second stage uses Nitrous Oxide/Propane pressure fed rocket engines to reach space.
Zegrahm ultimately expects to be able to fly two flights a week whilst the vehicles are being designed to be capable of upto two flights a day.
Space Cruiser ® and Sky Lifter ® are registered trademarks of Vela Technology Development, Inc.
As an example of how airbreathing engines could be used, the Pogo is intended as the first stage of a TSTO or MSTO launch system. Shown here using existing jet engines from the F-15 it is expected to reach at least Mach 2.5 and 80,000 ft before releasing a Pegasus-sized vehicle. Jet engines being developed for a proposed hypersonic commercial transport ("Hypersonic Transport Propulsion," Aerospace Engineering, June 1996, pp 7-11.) could take a much larger Pogo to Mach 5 and 100,000 ft. For many payload sizes, low-cost jet engines can do the job of rockets in the region where rockets are most expensive and inefficient.
SKYLON is the successor to HOTOL being developed by Reaction Engines Ltd. It is an unpiloted fully reusable aircraft-like vehicle capable of transporting 12 tonnes of cargo into space and is intended as a replacement for expensive expendable launchers in the commerical market.
An unusual and innovative strategy, SpaceCub is a sub-orbital four-seater rocket vehicle aimed at the future hobbyist market as an all-inclusive kit for an expected price of somewhere between a quarter and half $million, though you'll have to supply the fuel yourself. A possible X-Prize contender.
The Space Van is designed to carry 16 passengers plus a flight crew of 3 to LEO. A reusable booster stage accelerates the orbiter to around mach 3 at 30km altitude; the relatively low velocity compared to other booster designs allows a simpler and less complex design. Proposed by Space Tour, an unmanned cargo carrying variant is also on the drawing board.
|DELTA CLIPPER (DC-X,
DC-XA, CLIPPER GRAHAM)
The Delta Clipper was a proposed VTOL orbital vehicle. The DC-X and later DC-XA (derived from the DC-X) were low-speed, reusable test-vehicles built by McDonnell Douglas which flew 12 times between 1993-96, until suffering major fire damage after falling over when a leg failed to deploy on landing. On a total budget of about $100 million provided mainly by the US Department of Defense (DoD) and McDonnell Douglas Aerospace, they demonstrated that reusable rocket vehicles can be flown repeatedly and routinely by a small team - essentially like an aircraft.
Having inherited the project from the DoD, NASA cancelled it after spending some $40 million. Instead, NASA spent $1,300 million over 5 years on the X-33 and X-34, neither of which ever flew before being cancelled. Go figure!
It's notable that, apart from its computers, the DC-X could have been built 30 years earlier - and indeed a proposal for such a vehicle was made at that time by the Douglas company, a fore-runner of McDonnell-Douglas. Why it wasn't built, and why NASA cancelled the the DC-XA, are key to the stagnation in the space industry.
A sea-launched sub-orbital VTOHL rocket using LNG/ LOX engines, the CAC-1 was intended to carry six passengers from port city to port city as a rapid transit service, a transatlantic flight taking about 12 minutes. Designed and promoted by Advent Launch Services, the project was eventually scrapped after the company failed to raise sufficient financing through a deposit scheme. The original start of commercial service was to be July 4 1999. A former X-Prize contender.
A piloted, reusable SSTO VTOL rocket designed in the 1960s by Philip Bono of the (then) Douglas Aircraft company - the source of much SSTO VTOVL thinking. Base