Tomorrow, a NASA decision may be forthcoming on the cost-overrun and highly complex Mars Science Laboratory (MSL) mission. Will a decision be made to stay the course to Mars with a liftoff next year…or move it to 2011?…or decide its fate at a later time? But time is running out. The call itself is expected to come from NASA chief, Mike Griffin.

MSL is being tagged as “the first real astrobiology mission to Mars” - with a price tag sailing past $2 billion. The project has already exceeded the 15 percent “overguide”, (that’s an “overrun” in taxpayer parlance) set by Congress in the fiscal year 2008 NASA authorization law.

The next overguide benchmark is 30 percent. MSL’s total cost overrun is expected to be between 33 and 40 percent.

Why not delay the launch to 2011? Doing so will cost NASA an additional $300 million - $400 million.

MSL almost certainly will reach the 30 percent overguide ceiling say NASA insiders, at which point Congress has the authority to cancel the mission.

NASA officials anticipate that the Jet Propulsion Laboratory (JPL) — where MSL has been designed and is being built — has its hand out for more than $100 million extra that’s to be spread out over Fiscal Years 2009 and 2010.

Finding all the needed Mars moola for MSL is sure to have a ripple effect in other space science efforts. Possible sources of extra money for MSL include impacting the Jupiter Juno mission, the lunar Grail and LADEE missions, the newly picked MAVEN Mars Scout mission, and even NASA instruments to be flown on Europe’s ExoMars rover.

The technical readiness of the mission has to be weighed - and there’s worry that JPL’s MSL workers are already pushed to the limit in readying the huge Mars rover. They could be pushed even harder if a go for 2009 is given, raising the risk of errors and failure, according to senior management at NASA.

All concerned don’t want to see an expensive “smoking hole” or a “nuclear crater” on Mars instead of an MSL rock-solid soft landing on the red planet.

Indeed, one concern is MSL’s nuclear power sources. Smacking into Mars at high speed with those heat sources might lead to a subsurface melting of possible ice - a no-no in astrobiology circles.