The U.S. Defense Advanced Research Projects Agency (Darpa) awarded Boeing a $30.6 million contract to develop an airborne satellite launch vehicle the company has designed to attach to an F-15E Strike Eagle. The aim of Darpa’s Airborne Launch Assist Space Access (ALASA) program is to reduce the cost of routinely launching microsatellites into space.

Boeing said it will build up to 12 of the belly-mounted, 24-foot launch vehicles under the contract award the Department of Defense announced on March 21. An F-15 would release the ALASA launch vehicle at about 40,000 feet. The vehicle would then fire its four main engines and launch into low-earth orbit to deploy one or more microsatellites weighing up to a total of 100 pounds.

Small satellite payloads cost more than $30,000 per pound to launch and must share a launcher with other satellites, Darpa explains. The ALASA program, which the agency announced in 2011, endeavors to cut the launch cost of 100-pound satellite payloads by two thirds. The program’s second, build and demonstration phase is slated for completion by next February.

Boeing’s Phantom Works rapid prototyping arm designed a launch vehicle that economizes the number of engines used by a multi-stage rocket. “We developed a cost-effective design by moving the engines forward on the launch vehicle,” explained Steve Johnston, Boeing Phantom Works director of advanced space exploration. “With our design, the first and second stages are powered by the same engines, reducing weight and complexity.”

Launching payloads from an aircraft allows for more frequent missions and the ability to relocate to other runways instead of relying on fixed launch sites. It provides “launch point offset, which permits essentially any orbit direction to be achieved without concerns for launch direction limits imposed by geography at fixed-base launch facilities,” Darpa said.