11.09.2018

Experimental Spaceplane, formerly XS-1, is one of a number of ongoing DARPA programs related to launch and other space technologies. (credit: DARPA)

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Last week, the Defense Advanced Research Projects Agency celebrated its 60th anniversary with a conference, D60, held just outside Washington. It was an opportunity for past and current DARPA, as well as those who have worked with the agency, to talk about its past successes and failures and ongoing projects.

That included work in space. But the event was a reminder that, for an agency established in the aftermath of Sputnik, DARPA has had only a limited impact on the space industry. That’s particularly the case for launch, where recent decades have seen initiatives that have fallen short of expectations or failed entirely.

“We’ve been doing a series of programs over a span of almost 30 years” to try and reduce launch costs, said Todd Master, a program manager in DARPA’s Tactical Technology Office, during one panel session September 6. That dates back to the development of the Pegasus and Taurus vehicles by Orbital Sciences Corporation (later Orbital ATK and now Northrop Grumman Innovation Systems.) “Both of them were technical successes but never really got widespread adoption by either the DOD or the commercial industry, primarily because they were much too expensive.”

Later efforts ran into technical problems, like the Responsive Access, Small Cargo, Affordable Launch (RASCAL) program and, most recently, Airborne Launch Assist Space Access (ALASA), a program Master inherited when he joined DARPA two years ago. ALASA involved the development of a small launch vehicle that could be air-launched from an F-15, placing a 50-kilogram satellite into orbit.

“You can almost put something into space with an F-15 and the right launch vehicle underneath, but it requires a very energetic launch vehicle,” he said. That “very energetic” vehicle, using an unconventional mixed monopropellant fuel, is what doomed ALASA. “The challenge with an energetic fuel is that it’s very energetic. So, we wound up blowing up a few engines before we figured out that we weren’t exactly on right technical path.”

DARPA has not given up on space access, or other space-related projects, despite those problems. “DARPA has had significant activity in space that tends to oscillate over time,” said Tony Tether, former director of the agency, on another conference panel. “About every ten years it has a major program in space. We are in one of those cycles now.”

DARPA, in fact, has several space programs ongoing, both related to launch and other space technologies. Master is leading one effort, called the DARPA Launch Challenge, that is offering a prize for pursuit of responsive launch capabilities that the agency has tried to develop with more traditional programs in the past (see “The challenge of agile launch”, The Space Review, April 23, 2018). The competition offers a $10 million grand prize and several smaller prizes to companies whose vehicles are able to perform two launches on short notice from two separate ranges.

“This is significantly more money than we’ve offered before” in previous DARPA competitions, Master said. The original DARPA Grand Challenge, for example, which helped jumpstart the development of driverless cars, offered a $1 million grand prize, later increased to $2 million. “There’s a good reason for that. Launch vehicle development costs significantly more money than a self-driving car.”

DARPA also has the Experimental Spaceplane (formerly XS-1) program, where the agency is working with Boeing a reusable flyback first stage that could be used to deploy an expendable upper stage for placing medium-sized payloads in development. Boeing’s vehicle, dubbed Phantom Express, is in development, with its AR-22 engine—a repurposed Space Shuttle Main Engine—completing a series of static fire tests to demonstrate its ability to be used ten times in ten days, a major goal of the program.

In space, DARPA’s Robotic Servicing of Geosynchronous Satellites seeks to develop, as its name suggests, a robotic system capable of servicing satellites in geosynchronous orbit. DARPA is working with satellite manufacturer SSL on the system, and SSL will be able, after completing tests of the system on orbit, to use it commercially.

One other satellite effort, Blackjack, wants to leverage growing smallsat capabilities for military applications. The goal of the effort, said DARPA’s Paul “Rusty” Thomas at the conference, is to demonstrate the utility of constellations of dozens to hundreds of satellites “to provide a persistent, resilient ISR [intelligence, surveillance, and reconnaissance] network unlike any that we’ve seen before.” DARPA plans to award contracts for Blackjack satellites this fall, with a goal of placing a 20-satellite “subconstellation” into orbit by 2022.

But what about future space-related DARPA projects? A panel titled “The Future of Space” didn’t directly address what DARPA specifically should be working on in the future, but one of the panelists offered his wish list of technologies that need to be developed to make spaceflight more capable and robust.

“Where we are with space today is, to my mind, analogous to where we were with open ocean voyaging when what we had was wind power,” said Mike Griffin, the current undersecretary of defense for research and engineering and a former NASA administrator. “Lots of different technologies converged to make seapower a real thing.”

The key technology to make that analogous shift in space is nuclear propulsion, he said. “The no-brainer will be nuclear power and propulsion,” he said. “The only reason that’s not the case today is politics, and the politics of the irrational. If we do not grasp onto the rational, then others nations will and we’ll be watching it on TV.”

Another key technology—or, perhaps, suite of technologies—is in situ resource utilization. “I would say the most valuable aspect of returning to the Moon would be to extract liquid oxygen from the Moon and ship it up to zero potential,” rather that launch it from the Earth. “When we start using extraterrestrial materials, whether they come from asteroids or the Moon, that will be one of the technologies that gets us over the hump.”

“I’m fond of reminding people who want to talk about mining near Earth objects,” he added, “that the Moon is a near Earth object.”

A third key technology is “large-scale directed energy” to collect power in space and beam it not to the Earth, as space-based solar power advocates seek to do, but instead elsewhere in space. “Being able to beam that from spot to spot in the same way use copper wire to send power… that will be very critical.”

Griffin didn’t explicitly state that DARPA should pursue any of those technologies, only that they’re needed for humanity’s future in space. All would qualify as being “DARPA-hard” to some degree, although there are, or have recently been, work in many of those topics elsewhere, such as at NASA.

And as DARPA moves ahead with its current space programs, and ponders potential future ones, the checkered history of DARPA’s past space launch efforts does have a bright side. One of those previous programs was Force Application and Launch from CONUS (Continental US), or FALCON. And a beneficiary of that program was a small launch startup called SpaceX, with its Falcon 1 rocket (a naming coincidence.)

DARPA’s role in Falcon 1’s development was limited, and it had moved on by the time SpaceX got the vehicle to work on its fourth launch attempt. SpaceX eventually shelved the Falcon 1 because of a lack of demand, but it set the stage for SpaceX to pursue the bigger and ultimately far more successful Falcon 9 and Falcon Heavy, with the Big Falcon Rocket now in development.

Gwynne Shotwell, president of SpaceX, recalled the development of the Falcon 1 on the panel, and DARPA’s role in the rocket’s, and the company’s, development. “DARPA was enormously helpful to SpaceX,” she said. That success can balance out a lot of other failures.

Quelle: The Space Review