Boeing, Lockheed Martin and Virgin Galactic have been funded to explore different Alasa system concepts. Northrop Grumman, Space Information Laboratories and Ventions are working on enabling technologies that could be used by any or all of the system teams. The launch platform is to be a “fundamentally unmodified” aircraft. “We do not want an aircraft dedicated to the mission. That is key to the affordability of Alasa,” he says. Apart from software, Darpa's goal is that the aircraft “does not have any modifications preventing it from performing its primary mission.”

Boeing declines to detail its initial “point of departure” system concept, but Lockheed Martin says its design “uses a tactical aircraft to provide a high energy-state, reusable first stage, enabling launches from bases worldwide.” Lockheed's team includes Alliant Techsystems Operations and Defense Propulsion System. “All three have different approaches to the basic problem,” says Burnside Clapp, indicating that Virgin Galatic's Alasa concept is “what you might expect” given the company's plan to air-launch the SpaceShip2 suborbital passenger vehicle from the WhiteKnight2 carrier aircraft.

Darpa's goal is not only an air-launch system that can place a 100-lb. satellite in low Earth orbit for $1 million, but one that requires just 24 hr. from call-up to integrate and launch the payload, with the ability to replan the launch in flight and relocate the aircraft to a different airport on short notice. The aircraft must be able to operate from civil as well as military airfields, anywhere in the world, in a crisis.

“One million dollars to LEO including range costs is very aggressive. We will need lower range costs as well as [enabling] affordable manufacture of the launch vehicle,” Burnside Clapp says. Instead of ground-based radar tracking, Alasa will use onboard GPS/inertial position reporting via satellite. And instead of completely separate flight-termination hardware, the launch vehicle will continuously compute its impact point and make its own decision when to self-destruct. Some of this technology could spin off to update current ranges, he believes.

Darpa has budgeted $46 million for the 18-month first phase through September 2013, when it plans another competition to select at least one team to conduct up to 36 launches in 2015 “to demonstrate [the Alasa system] at a persuasive scale,” he says.

Alasa supports Darpa's System F6 fractionated satellite program, under which the functionality of a large, monolithic satellite will be provided by a networked cluster of smaller spacecraft flying in formation. “System F6 is disaggregating big satellites into their components to improve resilience. Alasa will do the same on the launch side,” Burnside Clapp says. “We will be able to launch spacecraft constellations incrementally at lower cost and be less exposed to a launch catastrophe.”