The US Department of Defense’s DARPA research arm is calling for proposals to develop a Mach 10+ suborbital space plane capable of launching small satellites.
Its Experimental Spaceplane (XS-1) programme aims to create a fully reusable unmanned…
The US Department of Defense’s DARPA research arm is calling for proposals to develop a Mach 10+ suborbital space plane capable of launching small satellites.
Its Experimental Spaceplane (XS-1) programme aims to create a fully reusable unmanned vehicle that could loft payloads of between 3,000lb and 5,000lb into low earth orbit.
With goals including being able to fly ten times in ten days, DARPA aims to cut the cost of access to space for small government and commercial satellites from more than US$50m to less than US$5m per flight.
Programme manager Jess Sponable said: “XS-1 aims to help break the cycle of launches happening farther and farther apart and costing more and more.
“It would also help further our progress toward practical hypersonic aircraft technologies and increase opportunities to test new satellite technologies as well.”
He said DARPA is looking for the most creative yet practical solutions possible for the vehicle, which aims to provide aircraft-like access to space without a large ground crew or expensive specialised infrastructure.
Once the reusable first stage flies at hypersonic speeds to a suborbital altitude, DARPA envisages it launching one or more expendable upper stages to take payloads to LEO before returning back to earth.
The plans are similar to those being developed by British manufacturer Reaction Engines for its Skylon space plane.
That plane will use the company’s SABRE engines to switch between jet and rocket modes mid-flight. Unlike conventional rockets, the engines would utilise oxygen when flying through the atmosphere, enabling Skylon to avoid relying on heavier liquid fuel that would make it more expensive to launch.
But even with that ability Skylon is aiming for speeds of Mach 5, and after receiving US$60m from the UK government the company said it needs more funding to develop a SABRE prototype by 2017. Flight tests have been pencilled in for around 2020.
DARPA has scheduled a proposals day for XS-1 on 7 October, with one-on-one discussions with potential partners being set for the next day.
The new programme is complementary to its Airborne Launch Assist Space Access (ALASA) scheme, which aims to modify existing conventional aircraft to loft smaller 100lb-class satellites.
Last year the UK’s Virgin Galactic, together with Lockheed Martin and Boeing of the US, won Phase 1 contracts to develop systems for ALASA that would be capable of launches for less than US$1m – a threefold reduction in current costs for this class of spacecraft.
ALASA’s Phase 2, scheduled to take place over the next two years, will include build and flight test demonstrations.
