Boeing and DARPA Aim for Mach 10
Boeing’s Phantom Works has scored a $6.6-million contract to continue working on a hypersonic drone aircraft as part of a program overseen by the Defense Advanced Research Projects Agency, the Pentagon’s fringe-science wing.
The XS-1 — short for “Experimental Spaceplane One” — is meant to test out a new way of quickly and cheaply launching satellites into low orbit. That requires the space plane to fly at hypersonic speeds up to Mach 10, essentially acting as the first stage of a rocket, lending velocity to a single-stage rocket carrying a small satellite.
The military hopes that using a hypersonic plane to help boost spacecraft into orbit will be cheaper and easier than traditional rocket launches. “Quick, affordable and routine access to space is increasingly critical for both national and economic security,” DARPA stated in a press release.
DARPA wants to test an XS-1 prototype no later than 2019. It’s actually possible that other companies could end up getting military funds to build prototypes. In the summer of 2014 DARPA gave Boeing, Northrop Grumman and Masten Space Systems $4 million apiece to do “phase one” design work.
Boeing has been keen to point out that the current, $6.6-million contract doesn’t cover vehicle production. “Boeing will continue design work in preparation for a phase two production competition,” said Cheryl Sampson, a Boeing spokesperson.
The U.S. military has struggled for decades to develop a reliable hypersonic vehicle. If XS-1 works out, it could help advance a wide range of other systems, from missiles and drones to manned aircraft.
Having sent a rocket on its way into orbit, the XS-1 would land like an airplane, refit, refuel, pick up another booster and satellite and, taking off from the same runway, head back into the upper atmosphere — up to 70 miles high — for another launch. DARPA wants an XS-1 to be able to fly a mission every 24 hours.
The key, according to Will Hampton — Boeing’s XS-1 program manager — is “applying operation and maintenance principles similar to modern aircraft.”
But that’s a tall order for a hypersonic vehicle, which must endure extreme heat and stress during high-Mach flight and must also be able to fly slow enough to land on a conventional runway. This combination of reliability, reusability, toughness and variable speed has so far eluded the designers in the United States — to say nothing of their counterparts in Russia and China.
DARPA and the U.S. Air Force tested unmanned hypersonic gliders in 2010 and 2011. Both tests ended prematurely when the gliders or their control links failed. DARPA and the Air Force had better luck with the hypersonic X-51 in trials in 2010 aand 2013. The U.S. Army successfully tested a hypersonic vehicle in 2011, but a follow-on experiment three years later ended in failure.
Virgin Galactic’s SpaceShipTwo, an experimental spaceplane for civilian applications, crashed during an October 2014 flight test, killing one of its two pilots.
To bolster its chances of success with the XS-1, Boeing has partnered with Blue Origin, the rocket company founded by Amazon.com billionaire Jeff Bezos. Boeing apparently wants to combine its XS-1 airframe with Blue Origin’s reusable BE-4 engine, which could produce half a million pounds of thrust.
The military wants XS-1 for space launches, but it’s easy to imagine other uses for a reliable hypersonic vehicle. In late 2013, Lockheed Martin announced it was developing the SR-72, a Mach-6 spy drone. “Hypersonic aircraft, coupled with hypersonic missiles, could penetrate denied airspace and strike at nearly any location across a continent in less than an hour,” said Brad Leland, Lockheed’s program manager for hypersonics.
“Speed is the next aviation advancement to counter emerging threats in the next several decades,” Leland added. And if Boeing and DARPA can get the XS-1 to work, it will be very, very speedy, indeed.