ARLINGTON, Va. — Developing new space capabilities, including low-cost responsive launch, remains a priority for the U.S. Defense Department’s advanced technology agency even as it also works on terrestrial alternatives to critical space-based systems.

In a briefing with reporters at its headquarters here March 25, Defense Advanced Research Projects Agency Director Arati Prabhakar said the agency’s modest investments in space were focused on ensuring the nation had a “robust capability” in space, particularly in space launch.

“A major focus of our space investments is a realization that, number one, we are extremely reliant on space,” she said. “The question we’re asking is: How do we make launch flexible, how do we change what’s possible to do on orbit once you get there, and then how do we change space situational awareness?”

The briefing was tied to the release March 26 of a DARPA report titled “Breakthrough Technologies for National Security.” The report summarized the broad range of projects underway by the agency, from information technology to synthetic biology.

The report only briefly covered space projects, highlighting efforts funded by DARPA that would allow satellites to launch more quickly and less expensively than current launch systems.

“DARPA is developing new approaches to launching satellites into orbit on short notice and at low cost,” the report states, “which have the potential to enable launch of satellites from virtually anywhere with just 24 hours’ notice and at a fraction of current costs.”

DARPA ALASA launch
ALASA is meant to launch satellites weighing up to 45 kilograms for less than $1 million per flight.

While the report does not go into details about those efforts, DARPA is currently funding two such projects. One, called Airborne Launch Assist Space Access (ALASA), uses a rocket under development by Boeing that would be launched from an F-15 fighter plane. ALASA’s goal it to launch satellites weighing up to 45 kilograms for no more than $1 million per flight.

In a Feb. 5 presentation at the Federal Aviation Administration’s Commercial Space Transportation Conference in Washington, Brad Tousley, director of DARPA’s Tactical Technology Office, said ALASA was on schedule to begin launches in 2016. DARPA plans to perform up to 12 launches of the ALASA system before making a decision on its future, including whether to hand over the system to another military agency or the private sector.

A second space access project at DARPA is Experimental Spaceplane 1 (XS-1). That effort is designed to develop a reusable first stage for a system that could, with an expendable upper stage, place payloads of up to 2,200 kilograms into orbit. Tousley said in February that the XS-1 project is currently in phase 1 studies awarded last year to Boeing, Masten Space Systems and Northrop Grumman.

Prabhakar said it is essential for the Defense Department to reduce launch costs and increase launch frequency. “Where we are today is that it takes years to schedule a launch and billions of dollars to put anything of substance on orbit,” she said. “Huge shifts are going to be needed there, I believe.”

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The DARPA report, though, also mentions efforts to develop replacements for space-based capabilities, in particular the Global Positioning System. “DARPA is developing a family of highly precise and accurate navigation and timing technologies that can function in GPS-denied environments,” the report states.

“I think we’ve made great progress” on those GPS alternatives, Prabhakar said, that could allow those efforts to shift to other organizations. “We’re starting to see some real transition opportunities there.”

However, Prabhakar added that those systems are not intended to be permanent replacements for space-based navigation systems, but instead something that can be used in situations where GPS is not for some reason available. “Doing this is just a phenomenal reminder of how dependent we are on space and how hard it is to live without just one thing we rely on from space, GPS,” she said.

Prabhakar said both the development of improved launch systems, and terrestrial alternatives for space-based systems, are driven by a realization that the space environment today is very different than even the recent past, given increased use of space by a growing number of nations and companies. “It’s a very different way of thinking about space than what we’ve done historically, all for good reason,” she said.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...