Last week, a 69 page NASA Powerpoint presentation on the costs of in-orbit fuel depots was leaked to SpaceRef.Com.   The July 21, 2011 document, a preliminary report of a more detailed in-house NASA study that at least one Congressman has requested and been promised, says it would be dramatically faster and cheaper to use existing rockets in combination with in-orbit fueling to get to the Moon, an asteroid, and other deep space destinations than to build the heavy-lift Space Launch System (SLS) rocket.  The Tea Party in Space (TPIS) is calling it an “integrity issue” for NASA.

“Propellant Depot Requirement Study Status Report, HAT Technical Interchange Meeting” is a pretty dry piece of literature, buried in tech-speak acronyms. It looks at four approaches to moving around human exploration in space, ranging from a baseline large (100 metric ton) rocket without refueling to using existing medium commercial launch vehicles to put up the pieces of a larger vehicle in-orbit, followed by fueling the vehicle from a propellant depot and going beyond low earth orbit to the Moon or an asteroid.

Building a heavy lift rocket is “dominated” by high unique fixed costs, says the report, because you won't fly it that much, while using existing commercial vehicles cuts out the expense and time of R&D to build a low-use rocket.   The study assumes there's no benefit costs for buying in bulk or lower prices at higher launch rates. 

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.

Congressman Dana Rohrabacher (R-CA (News - Alert)) has been waiting for NASA to forward over its in-orbit fuel depot study since July.   At a September hearing, he said NASA Administrator Charles Bolden had promised him documentation, but he later sent a letter to big rocket proponent and ex-NASA administrator Michael Griffin asking for Griffin's support in getting the agency to hand over the documentation.

TPIS bemoans the lack of “clamor” to fully investigate why NASA hasn't been more forthcoming with the cost-saving fuel depot study. Worse yet, SLS will consume at least $2.5 billion a year in R&D money across the next decade two decades.  

It isn't clear what TPIS will do next, but this is the sort of thing that would get Senator John McCain in a tizzy if he was paying attention to this and the proposed five year United Launch Alliance (ULA) launch buy that would effectively give Boeing and Lockheed Martin (News - Alert) an 80 percent monopoly of U.S. Air Force launches by guaranteeing a buy of 8 rockets a year – when the Air Force is projecting a peak of 5 launches per year, and an average of 3-4.