Darpa urgently wants a space plane it can fly day after day

The Pentagon is building another space plane. It already has one, the Air Force’s secretive X-37B, but DARPA, the Pentagon’s future-focused project’s research agency, wants another. This new space plane is the XS-1, with a deeply ambitious goal: deliver 3,000 pounds to orbit, daily, at a cost of $5 million for delivery.
In a solicitation that went out earlier this week, DARPA says it’s looking to “enable routine, low cost space access,” making the delivery of satellites to orbit as routine as, say, shipping cargo across the oceans. DARPA’s been at this for a while; they announced initial contracts in 2014, and have steadily kept up with the program, funding the second stage in 2015.
What makes the new announcement stand out is that it seems almost impatient. Space isn’t necessarily hard, but it’s hard to do cheap, and the cost savings are key to DARPA’s whole vision of the XS-1 program. Normally, a project with the agency goes through three phases, with ideas winnowed down and more successful alternatives buoyed by further funding.
The latest announcement is for both Phase II and Phase III at once, spelling out what a company needs to do to “finalize a design, fabricate, assemble, and fly the XS-1 through a series of test campaigns that will validate critical technologies and capabilities necessary to drive down cost and time-to-space by an order of magnitude.“
The immediate goals are for a successful booster launch on 10 consecutive days, and a launch carrying a payload of at least 900 pounds. While many DARPA projects often call for entirely new designs, the XS-1 program is open to existing spacecraft, if they can meet the standards set out by DARPA.