Skeptical about NASA’s plans—mandated by last year’s authorization act—to develop the heavy-lift Space Launch System (SLS), Congressman Dana Rohrabacher (R-CA) is demanding to find out details about alternative architectures that use smaller rockets coupled with propellant depots. In a press release this week, Rohrabacher is calling on NASA to release a study about propellant depots that he said NASA administrator Charles Bolden promised in July to provide, but has yet to do so. The agency, Rohrabacher noted, has played up the potential of depots in the past, “then the depots dropped out of the conversation, and NASA has yet to provide any supporting documents explaining the change.”
Advocates of propellant depot architectures argue that using them, in combination with existing launch vehicles, could obviate the need for a heavy-lift vehicle like the SLS. “The promise and potential of on-orbit fuel depots is the ability to use our existing fleet of launch vehicles, including Delta IV, Atlas V, Falcon 9, Taurus II, and Liberty, to enable deep space missions,” Rohrabacher said in his statement. “Using this system instead of a huge ‘monster’ rocket would increase flight rates, bringing greater efficiency into operations, increasing flight experience and providing data leading to greater reliability; and would increase the market potential for the commercial systems we will use for crew and cargo transportation to the International Space Station.”
This is not the first time Rohrabacher has pushed for the release of this NASA depot study. Earlier this month, as Space News reported, Rohrabacher wrote a letter to Bolden asking him for the study that the administrator had promised back in July. Bolden at the time had said that the study indicated that depot architectures were more expensive than the SLS approach, but Rohrabacher pressed him for details. “A wrong decision now could commit this nation to wasting tens-of-billons-of-dollars of taxpayer dollars,” Rohrabacher wrote. “My concern is that committing the nation to building a super-heavy-lift system is the wrong decision.” The article about the letter, though, came out around the same time as the SLS decision was announced, and hence got limited attention at best.
In this week’s statement, Rohrabacher tries a very different tack: seeking to enlist the support of former NASA administrator Mike Griffin. That seems at first an odd choice, since Griffin has been skeptical at best about the efficacy of propellant depots, such as in his testimony before the House Science Committee last week. Rohrabacher argues that if Griffin thinks depots aren’t the best approach, he would suport the release of a report that supports that. “Due to your continuing interest in this topic, as well as your strong belief in the importance of accountability and transparency in human space exploration, which you reiterated in [last week's] testimony, I ask that you join me in calling for NASA to make public the analysis and conclusions performed as part of the Human Exploration Framework Team activities,” Rohrabacher wrote in a letter to Griffin included in the press release.