WASHINGTON — U.S. Rep. Dana Rohrabacher (R-Calif.) called on NASA Administrator Charles Bolden to deliver the space agency’s assessment of a space exploration architecture that uses in-space propellant depots and a fleet of commercially built rockets as an alternative to a single government-owned heavy-lift vehicle.

In July, Bolden testified before the House Science, Space and Technology Committee, answering questions from lawmakers about NASA’s delay in producing a reference design for the Space Launch System (SLS), a heavy-lift rocket for deep-space missions that Congress has ordered NASA to build.

In a Sept. 6 letter, Rohrabacher pointedly reminds Bolden that he testified during the July hearing “that the studies have been done, and the fuel depot solution proved to be more expensive.”

Rohrabacher wrote in the letter, a copy of which was obtained by Space News, that a propellant depot-based architecture might allow NASA to fly astronauts beyond low Earth orbit aboard the Multi-Purpose Crew Vehicle (MPCV) sooner and more often than would be possible if the capsule had to wait on SLS for a ride into space. With depots, Rohrabacher said, commercially operated rockets could be used to send MPCV on deep-space missions. Commercial rockets could also be tapped to fly propellant depots into space, and to deliver a serviceable supply of rocket fuel in low Earth orbit, Rohrabacher said.

“We need to know that NASA completed a fair and balanced analysis to justify a down-select to a super-heavy-lift launch vehicle, which is a commitment of tens-of-billions of taxpayer dollars,” Rohrabacher wrote in the letter.

MPCV is the congressionally mandated companion vehicle for SLS.

NASA spokesman J.D. Harrington did not immediately return a request for comment.

Rohrabacher has lately been as vocal in his support for commercial space companies as he has been in his opposition to SLS.

Proponents of depot-based exploration argue storing propellant in space would allow crews and cargo to launch from Earth aboard smaller rockets. If propellant was available in space, rockets would no longer have to launch with all the fuel they will need already on board. Rather, the rockets could head to a propellant depot in low Earth orbit and pick up the fuel needed to reach deep space.

NASA is interested in in-space propellant storage and transfer — the underpinning technology for depots — and in August awarded four companies study contracts totaling $2.4 million to develop concepts for storing and transferring cryogenic propellants in space.


See Rep. Rohrabacher’s Letter Here

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.