Propulsion tests prove concept, but further development depends on backers
Space Launch is seeking backers for its low-cost, small-payload launch system after completing funded testing of the air-breathing propulsion concept on which the design is based. The system would use jet engines with mass injection pre-compressor cooling (MIPCC) to boost an existing supersonic aircraft out of the atmosphere.
In ground tests at Mojave, California, a Pratt & Whitney F100-200 modified with MIPCC was operated at a simulated Mach 3.2 and 80,000ft (24,400m) – well beyond the jet fighter engine’s normal operating conditions. Results were “right on our analytical predictions”, says Darren Festa, director, business development.
The US Defense Advanced Research Projects Agency (DARPA)-funded MIPCC testbench simulates high-Mach flight by filling a large plenum with the exhaust from a J79 jet engine, augmenting the hot gas with liquid air and oxygen to get the correct temperature, pressure and composition, then feeding it to the MIPCC duct of the F100 test engine.
The concept involves injecting water and oxygen upstream of the compressor to both increase mass flow and cool the engine, enabling it to operate to higher speeds and altitudes and allowing a MIPCC-powered aircraft to “zoom climb” to above 90,000ft then coast out of the atmosphere to release an expendable upper stage carrying a micro-satellite.
Testing started under DARPA’s Rascal programme to demonstrate the rapid launch of 150kg (330lb) payloads into low Earth orbit using an M3-plus aircraft powered by four modified F100s. The project was terminated last year, but Space Launch continued work on MIPCC and is in talks with DARPA on follow-on testing, says Festa.
The California-based company is seeking backers for a more modest system capable of launching 10-20kg nano-satellites. This would be based on an existing aircraft – the company’s website shows a McDonnell Douglas F-4 fighter – with MIPCC-modified engines.
GRAHAM WARWICK/WASHINGTON
Source: Flight International
