Keep the shuttles flying? It’ll cost you

How many flights?
The launch manifest under the first option — not counting the November launch of space shuttle Endeavour — would include 12 flights during the next four years: four in 2009, four in 2010, three in 2011 and one in 2012. Space shuttle Discovery would make its final flight in August 2010 and Atlantis in February 2011.

The 22-launch manifest under the five-year extension option features four missions in 2009 and three in each of the following six years. Atlantis would be retired after 2010 and available to provide spares to Discovery and Endeavour.

While preserving NASA's ability to fly astronauts to the space station until Ares 1 and Orion come on line — albeit at a cost of $11.4 billion — the five-year shuttle extension would severely impact various other elements of the Constellation, including the heavy-lift Ares 5 cargo launcher.

Ares 1 and Ares 5 will lift off from a pair of launch pads currently used by the shuttle. Modifications to Pad A to accommodate the Ares 5 are scheduled to begin in 2012, but a five-year extension of shuttle operations would delay that by two to three years unless NASA can find a way to use Pad B both for shuttle missions and Ares 1 test flights, the report said. The five-year option also likely would require NASA to move Ares upper stage manufacturing operations to another facility at Michoud, the report said. The change could delay Ares 5 by 18 to 25 months.

More unanswered questions
Other issues NASA would have to resolve to keep the shuttle flying five more years include:

• A 15-month to 16-month development delay on the Ares J-2X upper stage engine, unless NASA can modify its A1 test stand at Stennis Space Center in Mississippi to accommodate testing of both that engine and the space shuttle main engine.
• The availability of North American Rayon, a specialty material used to manufacture shuttle and Ares solid-rocket motor nozzles, is limited, which means the capacity to produce Ares vehicles would be drastically reduced.
• Space shuttle solid rocket booster production would require $23 million in 2009 for skills retention, and the insulating material for the motor would require a new indemnification agreement or qualification of a replacement material, as production is scheduled to end in 2010.
• Orion's space station rendezvous and docking system would have to be altered to allow it to dock at a different location so the shuttle can continue to use its primary docking port.
• NASA would have to recertify vendors soon to enable extended operations.

The 2015 option assumes that the space shuttle will cease operations as soon as a replacement becomes available, be it Orion-Ares 1 or a commercially developed alternative.

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