Could NASA Use Space Based Fuel Depots to Explore Space? (ContributorNetwork)

A kerfuffle has arisen over the revelation of a study NASA conducted of the use of space based fuel depots in conjunction with existing launchers in lieu of building the heavy lift Space Launch System.

Some space advocates are demanding that the SLS project be scrapped and yet another space exploration plan using fuel depots be implemented. Others respond that fuel depots are too risky and too complicated. NASA found the study unconvincing and too singularly focused.

What Does the NASA Study Say?

The NASA study looks at several scenarios involving missions to Near Earth Asteroids or the moon using existing or soon to be built launch vehicles such as the Delta IV and the Falcon Heavy and fuel depots. The idea is to launch a fuel depot that would contain cryogenically stored rocket fuel into low Earth orbit. Several other launches of space craft would be required to fill the depot. Then more launchers to deliver the Multi Purpose Crew Vehicle and either a lander, for lunar missions, or a habitation module, for asteroid missions, would be required. The spacecraft would dock at the fuel depot, top off, and then proceed on their mission.

What are the advantages of fuel depots?

The NASA study claims "tens of billions of dollars" cost savings and an advance to the left of the schedule, allowing missions to the moon or asteroids sooner than those using a heavy lift SLS. Other advantages claimed include multiple launches over several months, which increases workforce experience which in turn enhances reliability and reduces costs. A group calling itself Tea Party in Space is championing the use of fuel depots,

What are the disadvantages?

Because of the many launches required using the fuel depot architecture, no more than one mission to either the moon or an asteroid can be launched every two years. Multiple launches create more opportunities for mission delay or even failure due to a launch failure. This can prove problematic for asteroid missions, the windows of which are few and far between. While the cost of developing an SLS heavy lifter is avoided, there is likely no savings in operational costs if one adds up the published costs of launching several Delta IVs or Falcon Heavies vs. a few SLSs. The storing of cryogenic fuels in space and its transfer to spacecraft are unproven technologies. Former NASA administrator Mike Griffin pointed out these drawbacks in recent congressional testimony,

What is NASA's Response?

NASA is suggesting that it eventually intends to combine the use of the SLS heavy lifter with fuel depots. The idea is that fuel depots would not be in the "critical path" of developing the capability to go back to the moon or to an asteroid. Instead, space based fuel depots would be enhancement, allowing heavier payloads to be sent to various destinations in the solar system. This is in keeping with recommendations of the Augustine Committee, which advised the building of a heavy lifter and further study of fuel depots.

Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker. He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post, USA Today, the L.A. Times and The Weekly Standard.

Source: http://us.rd.yahoo.com/dailynews/rss/science/*http%3A//news.yahoo.com/s/ac/20111024/us_ac/10279703_could_nasa_use_space_based_fuel_depots_to_explore_space

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