DARPA Picks Boeing for XS-1 Program

DARPA’s Experimental Spaceplane (XS-1) program seeks to build and fly the first of an entirely new class of hypersonic aircraft that would break the cycle of escalating launch costs and make possible a host of critical national security options. As the next step toward a future of routine, responsive, and low-cost space access, DARPA has awarded Phases 2 and 3 of the program to The Boeing Company. (Credit: Boeing)

WASHINGTON, DC (DARPA PR) — DARPA has selected The Boeing Company to complete advanced design work for the Agency’s Experimental Spaceplane (XS-1) program, which aims to build and fly the first of an entirely new class of hypersonic aircraft that would bolster national security by providing short-notice, low-cost access to space.

The program aims to achieve a capability well out of reach today—launches to low Earth orbit in days, as compared to the months or years of preparation currently needed to get a single satellite on orbit.

Success will depend upon significant advances in both technical capabilities and ground operations, but would revolutionize the Nation’s ability to recover from a catastrophic loss of military or commercial satellites, upon which the Nation today is critically dependent.

“The XS-1 would be neither a traditional airplane nor a conventional launch vehicle but rather a combination of the two, with the goal of lowering launch costs by a factor of ten and replacing today’s frustratingly long wait time with launch on demand,” said Jess Sponable, DARPA program manager. “We’re very pleased with Boeing’s progress on the XS-1 through Phase 1 of the program and look forward to continuing our close collaboration in this newly funded progression to Phases 2 and 3—fabrication and flight.”

The XS-1 program envisions a fully reusable unmanned vehicle, roughly the size of a business jet, which would take off vertically like a rocket and fly to hypersonic speeds. The vehicle would be launched with no external boosters, powered solely by self-contained cryogenic propellants. Upon reaching a high suborbital altitude, the booster would release an expendable upper stage able to deploy a 3,000-pound satellite to polar orbit. The reusable first stage would then bank and return to Earth, landing horizontally like an aircraft, and be prepared for the next flight, potentially within hours.

In its pursuit of aircraft-like operability, reliability, and cost-efficiency, DARPA and Boeing are planning to conduct a flight test demonstration of XS-1 technology, flying 10 times in 10 days, with an additional final flight carrying the upper-stage payload delivery system. If successful, the program could help enable a commercial service in the future that could operate with recurring costs of as little as $5 million or less per launch, including the cost of an expendable upper stage, assuming a recurring flight rate of at least ten flights per year—a small fraction of the cost of launch systems the U.S. military currently uses for similarly sized payloads. (Note that goal is for actual cost, not commercial price, which would be determined in part by market forces.)

To achieve these goals, XS-1 designers plan to take advantage of technologies and support systems that have enhanced the reliability and fast turnaround of military aircraft. For example, easily accessible subsystem components configured as line replaceable units would be used wherever practical to enable quick maintenance and repairs.

The XS-1 Phase 2/3 design also intends to increase efficiencies by integrating numerous state-of-the-art technologies, including some previously developed by DARPA, NASA, and the U.S. Air Force. For example, the XS-1 technology demonstrator’s propulsion system is an Aerojet Rocketdyne AR-22 engine, a version of the legacy Space Shuttle main engine (SSME).

Other technologies in the XS-1 design include:

  • Advanced, lightweight composite cryogenic propellant tanks to hold liquid oxygen and liquid hydrogen propellants
  • Hybrid composite-metallic wings and control surfaces able to withstand the physical stresses of suborbital hypersonic flight and temperatures of more than 2,000o F
  • Automated flight-termination and other technologies for autonomous flight and operations, including some developed by DARPA’s Airborne Launch Assist Space Access (ALASA) program

XS-1 Phase 2 includes design, construction, and testing of the technology demonstration vehicle through 2019. It calls for initially firing the vehicle’s engine on the ground 10 times in 10 days to demonstrate propulsion readiness for flight tests.

Phase 3 objectives include 12 to 15 flight tests, currently scheduled for 2020. After multiple shakedown flights to reduce risk, the XS-1 would aim to fly 10 times over 10 consecutive days, at first without payloads and at speeds as fast as Mach 5. Subsequent flights are planned to fly as fast as Mach 10, and deliver a demonstration payload between 900 pounds and 3,000 pounds into low Earth orbit.

Another goal of the program is to encourage the broader commercial launch sector to adopt useful XS-1 approaches, processes, and technologies that facilitate launch on demand and rapid turnaround—important military and commercial needs for the 21st century. Toward that goal, DARPA intends to release selected data from its Phase 2/3 tests and will provide to all interested commercial entities the relevant specs for potential payloads.

“We’re delighted to see this truly futuristic capability coming closer to reality,” said Brad Tousley, director of DARPA’s Tactical Technology Office (TTO), which oversees XS-1. “Demonstration of aircraft-like, on-demand, and routine access to space is important for meeting critical Defense Department needs and could help open the door to a range of next-generation commercial opportunities.”



  • JamesG

    Uh… right. Unless this is a ploy to bring a preexisting previously black project into the light without declassifying, there’s not a chance Boeing is going to make those dates even WHEN DARPA hands Big B a blank check. Probably never will considering the ridiculously optimistic performance specs.

    You know that tingling feeling you got when reading this post? That was the sensation you get when you stare into a bottomless pit your government is going to try to fill with your money.

  • windbourne

    It will be interesting to see if it is even close to being on-time.

    Personally, I find it interesting the goals of this.
    $5 million / flight, and turn around in 24 hours 10x in 10 days.
    This is pretty small load though.
    .5-1.5 tons to LEO.

    I suspect that by next year this time, SpaceX will have their 15 tonnes to LEO for under 15 million costs ( what they charge will be a different issue ).

  • Larry J

    The DARPA goals are to not only lower the costs of getting payloads of that size to orbit compared to existing systems but to greatly increase the launch cadence. Even SpaceX takes a lot of time between signing a contract for launch services to delivering the payload to orbit. The military wants the ability to launch small satellites quickly to replace those taken out by an adversary.

  • windbourne

    I suspect that last part is going to be very important.
    Hopefully not,but ….

  • Zed_WEASEL

    If the USAF wants to quick launch a lot of small satellites in quick succession from a single platform. They would would be better off just converting some 747 like the Virgin Orbit’s Cosmic Girl. A lot cheaper than tinkering with the SSME.

  • The news about it using a SSME (essentially) is a little weird imo. Especially since
    they are talking about AJRD making them from spare parts found in their
    warehouses and NASA centers…If I remember correctly, SSME is not
    re-startable. This means that the spaceplane will launch from one
    airport, and land on another. Moreover, the SSME was not known to be a
    very fast turnaround engine. And this program is about 10 flights in 10

    Lastly, what the hell happened to Blue Origin? They were the original engine partner for Boeing in this program.

  • JamesG

    The last part won’t matter. They would be deploying sats into a minefield of debris and they won’t last long at low alt. and/or will simply provide more grist to Kessler’s mill.

    This toy spaceplane won’t be able to lift anything armored enough to be worth putting into orbit. If it actually works at all. It is a literal waste of money.

  • Andrew Tubbiolo

    A LOX/H2 operationally responsive space launcher? Doubtful. I’m believe it if it had something like pintle injection for JP-8 and ran it off of JP-8/LOX. Every USAFB has JP-8, and LOX. The old Fastrac engine program comes to mind.

  • therealdmt

    “They would be deploying sats into a minefield of debris…”

    That’s what I was thinking. Still, in an all out war, even a few hours of data or comms might be critical. The capabilities enabled by space-based assets are a big part of what allows the US to have the only world-spanning military force, but the vulnerability of those assets means that it’s all a bit of a house of cards. If the gloves come off, those satellites are going down, and then, due to our reliance on those satellites that’s built into everything we do, we’ll be a bit like a great heavyweight boxer whose suddenly blinded in the ring. Uh oh

    Rapid replenishment could be one strategy (or one part of an overall strategy including other strategies such as hardening, maneuverability, intercepting, etc.) for dealing with that vulnerability, but could we really replace ’em faster than Russia and/or China could shoot ’em down? And then, like you say, the debris from a first attack wave will be constantly doing part of the job for them, with no further effort on their part needed.

    A real tricky problem, for sure.

  • JamesG

    We had a world-spanning military long before we ever had satellites.

    Perhaps we should be addressing WHY we are so dependent/vulnerable on space based assets instead of trying to find ways to remain so. Everything from teaching soldiers map reading, land navigation, and signalling and naval officers nautical navigation, to adjusting TTPs so that they are not a technology driven micromanger’s dream.

    When the war in LEO starts, everyone is going to be blinded equally. Its who is prepared for it and can adapt to it fastest that is going to win. Not who can burn money the fastest.

    But that would get away from selling ever more expensive gadgets. Can’t do that.

  • JamesG

    This whole thing does have a soup-sandwich feel to it…

  • Saturn13

    nd fast turnaround of military aircraft. For example, easily accessible
    subsystem components configured as line replaceable units would be used
    wherever practical to enable quick maintenance and repairs.
    Just like the F-4 I worked on. Replaced a lot of LRU. 60 year old tech. We did have to repair the LRU though.

  • Jeff2Space

    The USAF demonstrated the launching of a (quite large) missile from a C-5 Galaxy long ago. If they wanted to do air launch, that would be the way to go.

  • Jeff2Space

    Because satellites are perfect for facilitating global communications and surveillance (optical, signal intelligence, and ICBM launch detection). There really is no suitable ground based replacement for ICBM launch detection. And anything in the air would be shot down (e.g. remember the U-2 that was shot down).

  • JamesG

    “Because satellites are perfect for facilitating global communications and surveillance”

    Sure, but they aren’t the only way to do it. And they have always been extremely vulnerable.

    There really is no suitable ground based replacement for ICBM launch detection.

    Not really. We would just have to dust off BMEWS, most of which is already reconstituted as part of NDM.

    And anything in the air would be shot down (e.g. remember the U-2 that was shot down).

    No SR-71 was ever shot down.

  • Pete Zaitcev

    Look at the upside: at least it’s not a SCRAMJET!

  • Jeff2Space

    True, but the SR-71s have been in museums for quite some time. The U-2 is fulfilling that role now.

  • JamesG

    The U-2 isn’t busting anyone-that-could-care-about-it’s airspace.

  • redneck

    Spelling flame, there is no R in SCAMJET.

  • Jeff2Space

    I know, which is why I said satellites are our best asset for intel collection. Yes, we *could* develop an SR-71 replacement to fly over enemy territory, but it would either be shot down right away or after a few tries. Ground to air missiles are quite good these days.

    There simply is no good (non-orbital) replacement for our existing ICBM launch detection satellites which operate continuously.

  • JamesG

    “Ground to air missiles are quite good these days.”

    True. But so are low observable UAV/UCAVs.

    ” There simply is no good (non-orbital) replacement for our existing ICBM launch detection satellites which operate continuously.”

    Eh, it depends on what the requirements are. If you want to see the launch sites and boost phases so your politicians and generals can dither for a few minutes before launching a counter strike, yes. But if you just need to know they are coming to do the same, the old radar arrays work fine.

    We should be careful not to get sucked into expensive nostalgia for the 70s and 80s. Even if other nations develop peer level defensive and offensive strategic weapons, the US still has enough power to smite the rest of the world. But beyond that, none such has any incentive or motive to launch such an attack. The states and non-state actors who do, aren’t going to use an ICBM and surely don’t have the capacity to destroy a significant percentage of orbital asset capacity.

    The real threat is going to come out of the blue, not where we’ve concentrated our power. And by spending an inordinate amount of our resources because its comfortable to hide behind our tech (and the MIC benefits enormously), we may be blind to that threat until it strikes.

  • publiusr

    Poor Masten. No love or money.