Top NASA managers will decide next week the fate of the Mars Science Laboratory, a nuclear-powered astrobiology rover that already has cost $1.5 billion and is likely to hit the 30-percent overrun ceiling that could trigger cancellation by Congress.

Officials from the agency's Mars Exploration Program (MEP) and the Jet Propulsion Laboratory (JPL) are set to brief Administrator Mike Griffin and Science Associate Administrator Ed Weiler on the program next week.

Doug McCuistion, the MEP manager, told the NASA Advisory Council Oct. 2 that JPL probably will ask for a $100 million-$150 million increase to its $223 million fiscal 2009 budget - spread over FY '09-10 - to meet its September 2009 launch window. The program overran its $355 million FY '08 budget by $190 million, and is expected to overrun the total program cost reflected in the FY '08 NASA authorization by 33-40 percent. This could bring its total cost to more than $2 billion (Aerospace DAILY, Feb. 28). McCuistion doesn't expect JPL's request to be granted, due to the center's traditionally shaky cost estimating, but outside cost estimates have been prepared as well.

A slip to the 2011 launch window will add another $300 million-$400 million to the price tag, but Weiler worries JPL is so stretched trying to make the 2009 window that the result could be "a nuclear crater on Mars" from the rover's radioisotope thermoelectric generator. The MEP is out of cash, and the agency's Planetary Science Division has identified only about $70 million it can pull from other programs in the near term.

The MEP is stretched to its limits, McCuistion said, with no funding for technology development and "next to nothing" for education and public outreach. Research & Analysis (R&A) funding hasn't been touched yet, but NASA has faced harsh criticism from Capitol Hill for past R&A cuts. Since MSL itself can't be scaled back, additional funding might have to come from other Mars efforts, including development work for a future sample return mission, or from whatever mission is approved for the 2016 launch opportunity.