Wednesday, October 19, 2011

Did Congressional SLS Mandate Bury NASA Fuel-Depot Study?


Representative Dana Rohrabacher. Image source: U.S. House of Representatives.

Space News reported on September 13 that Rep. Dana Rohrabacher (R-CA) asked 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" ...

“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.


Now an October 12 SpaceRef.com article suggests Rohrabacher had reason to be suspicious.

... [D]espite what NASA may or may not have been telling Rep. Rohrabacher about its internal evaluations regarding the merits of alternate architectures that did not use the SLS (and those that incorporated fuel depots), the agency had actually been rather busy studying those very topics.

And guess what: the conclusions that NASA arrived at during these studies are in direct contrast to what the agency had been telling Congress, the media, and anyone else who would listen.

This presentation "Propellant Depot Requirements Study - Status Report - HAT Technical Interchange Meeting - July 21, 2011" is a distilled version of a study buried deep inside of NASA. The study compared and contrasted an SLS/SEP architecture with one based on propellant depots for human lunar and asteroid missions. Not only was the fuel depot mission architecture shown to be less expensive, fitting within expected budgets, it also gets humans beyond low Earth orbit a decade before the SLS architecture could.

Moreover, supposed constraints on the availability of commercial launch alternatives often mentioned by SLS proponents, was debunked. In addition, clear integration and performance advantages to the use of commercial launchers Vs SLS was repeatedly touted as being desirable: "breaking costs into smaller, less-monolithic amounts allows great flexibility in meeting smaller and changing budget profiles."


Click here to download the report. You will need Adobe Acrobat Reader to read the report.

Satellite Spotlight contributing editor Doug Mohney comments:

By using existing hardware and a propellant depot, the first asteroid mission can be flown in 2024 at a cost of $64 billion – and remember, that's before buying in bulk or lower pricing due to competition and lower launch rates. Using a big rocket – a.k.a. the Space Launch System – costs $143 billion with the first mission in 2029; more than double the cost and 5 years later.

The advantages for using existing commercial launchers are numerous, according to the presentation. “Tens of billions of dollars” of cost savings and lower “up-front” costs, accrue. Missions happen by 2024 using “conservative budgets” with launches happening every few months like clockwork, rather than a single large rocket launch every 12 to 18 months. More launches provide an experienced and “focused” workforce to improve safety, as well as providing experience to lower cost and provide higher launch reliability.

Since multiple launches are used, multiple competitors can compete for delivering propellant to orbit and open the door for international partners to contribute. And as a nice benefit, it creates a stimulus for the U.S. commercial launch industry, because more flights open up for existing rockets.


Edward Ellegood of the Florida SpaceReport observes:

Seems like NASA's hands were tied on this. President Obama had wanted to delay a heavy-lift rocket decision until 2016, in favor of other space priorities. But powerful members of the Senate (and some in the House) pushed hard for the SLS, and NASA was blamed repeatedly (and threatened harshly) for putting up roadblocks to SLS. Release of the fuel depot study would surely have been viewed as another roadblock by the Senate.

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