Space Launch looks at going it alone as US agency focuses on Falcon small vehicle
Small US firm Space Launch hopes to continue work on a satellite-launching supersonic aircraft, despite a decision by the US Defense Advanced Research Projects Agency (DARPA) not to proceed with a flight demonstration.
California-based Space Launch completed a "successful preliminary design review of a closed point design" in November last year, at the end of Phase 2 of DARPA's Responsive Access Small Cargo Affordable Launch (Rascal) programme, says chief executive Bill Olson. But DARPA has decided not to proceed into Phase 3 - flight demonstration - and instead is to focus its efforts on the Falcon small launch vehicle programme.
The Rascal design comprises a high-speed, high-altitude aircraft carrying a two-stage expendable rocket capable of boosting a 150kg (330lb) satellite into low-Earth orbit (LEO). The aircraft, which is designed by Scaled Composites, is powered by four turbojets incorporating mass injection pre-compressor cooling (MIPCC).
This injects liquid oxygen and water into the inlet to cool the compressor and increase massflow, allowing operation to higher speeds and altitudes.
The MPICC turbojets, based on Pratt & Whitney's F100 fighter engine, enable the aircraft to take off conventionally, accelerate to beyond Mach 3 then "zoom climb" to above 200,000ft (61,000m) - essentially outside the atmosphere - to deploy the expendable upper stage from its payload bay, before returning to a runway landing.
DARPA's goal was to launch a small intelligence-gathering satellite on an hour's notice, then be able to orbit a second spacecraft within 24h, at a cost of $10,000/kg. Since the Rascal programme was started in 2002, however, significant progress has been made in the Falcon programme, which is developing a responsive capability to launch 450kg payloads for less than $5 million, the agency says.
Under the original programme, DARPA planned to build a prototype Rascal system and conduct two demonstration flights beginning in 2008.
Olson says Space Launch is keeping the critical members of its team together as it looks at how to proceed with the programme.
"Lowering the cost of launch is the way to proceed for small payload and the Rascal model is much better [than expendable rockets]."
The team plans to review the point design "and see if we can do better", he says. Space Launch will continue rig testing of the MIPCC concept with funding from DARPA, which says results from Phase 1 and 2 were "wholly worthwhile".
An accident at the rig in Mojave, California shut down testing for several months last year, says Olson, delaying tests of the MIPCC-modified F100. These are due to begin shortly, he says.
Source: Flight International
