Space Launch Corp. is trying, so far without success, to drum up U.S. Defense Department interest in a scaled-down version of a small-satellite launching system that the company designed under a program that has been marked for cancellation.

The proposed system consists of a modified military aircraft that would take off and land from a runway and launch expendable rockets carrying 10- to 20-kilogram satellites from high altitudes. The design is based on the more complex Response Access, Small Cargo and Affordable Launch (RASCAL) system, which was intended to handle satellites weighing roughly 150 kilograms.

The U.S. Defense Advanced Research Projects Agency (DARPA) sponsored the RASCAL effort as part of a broader effort to foster development of rockets capable of launching small military satellites inexpensively on short notice. A demonstration flight was planned for 2008, but DARPA elected to cancel the program after it ran into developmental snags.

Robert Parker, chief technology officer and director of product development at Irvine, Calif.-based Space Launch, said the company could build on the RASCAL work done to date to demonstrate the capability to launch payloads — albeit much smaller ones — for about $1 million apiece. He declined to say, however, how much more funding his company would need to complete development of such a system.

DARPA awarded Space Launch a $22 million RASCAL design and development contract in 2003. The company expects to wrap up its work under the contract soon with tests of a special component called a Mass Injected Compressor Cooled System that would allow an aircraft to operate temporarily at altitudes beyond the reach of conventional, air-breathing jet aircraft, he said.

DARPA initially estimated that the RASCAL program would cost $88 million through the 2008 flight demonstration, a projection that was based on the assumption that Space Launch could use a modified U.S. Air Force fighter jet as the system’s first stage. It quickly became clear, however, that the system would require a custom-designed aircraft, and that caused RASCAL’s developmental cost projections to soar.

The scaled-back system now being proposed by Space Launch would make use of an F-4 fighter jet equipped with the Mass Injected Compressor Cooled System for operations near the edge of the atmosphere, Parker said.

Space Launch has been pitching its RASCAL resurrection idea to Pentagon organizations including DARPA, the Air Force Space and Missile Systems Center in Los Angeles, which buys satellites and launch vehicles, and the Air Force Academy in Colorado Springs, Colo., Parker said. The idea is to sow seeds of support for the effort, he said.

The Space and Missile Systems Center has yet to climb on board. Air Force Col. Richard White, director of the center’s Detachment 12, which finds rides for small experimental military payloads, characterized the need for satellites in the 10- to 20-kilogram class “small” — perhaps one per year. The service is more interested in 180-kilogram spacecraft platforms that could host multiple experiments , White said in a written response to questions.

Jan Walker, a DARPA spokeswoman, said the agency is aware of the Space Launch proposal but is not interested.

But the Air Force Academy, whose students on occasion build spacecraft in the size class that Space Launch is talking about, might have a different view.

John Van Winkle, a spokesman for the school, said he expects students there to do “a fair amount of work” on satellites in the 10- to 20-kilogram size range in the years to come. He noted that academy students built Falconsat-2, a 19.5-kilogram satellite designed to monitor ionospheric effects that could interfere with satellite navigation and communications signals whose launch is scheduled for Sept. 30.

DARPA is sponsoring that launch, which will be the first of the Falcon-1 expendable rocket developed by Space Exploration Technologies of El Segundo, Calif., Van Winkle said.