NASA’s mega Mars rover — the Mars Science Laboratory (MSL) — seems to be headed for a major decision point next month. Will it fly in 2009 or be delayed until 2011?

A major review meeting on the nuclear-energized MSL is slated for NASA Headquarters in October - with the space agency then or shortly after deciding whether the powerful rover is ready to set sail toward Mars next year.

Meanwhile, the folks building the mechanized wonder at Jet Propulsion Laboratory (JPL) are number crunching, coming up with current dollar numbers for the already over-budget mission. At last ka-ching of the cash register the planetary mission was roughly $2 billion.

There are cost implications for delaying MSL’s sendoff to the red planet to 2011.

Hall talk at yesterday’s Mars Exploration Program Analysis Group (MEPAG) meeting in Monrovia, California seems to suggest that the 2009 launch is still the plan. MEPAG is chartered by NASA Headquarters to assist in planning the scientific exploration of Mars.

The buzz at MEPAG is that the cost of missing the launch is so high that JPL and the MSL team are running hard to get the spacecraft off to Mars in the fall of 2009.

So a go/no go decision on the one-off MSL appears to remain up in the air at the moment…so keep an eye on this one.