Concerns have been raised about how to pay for the project's escalating costs and whether engineers can ready the rover in time for a safe launch next fall. NASA has poured $1.5 billion into the project but the final price tag is expected to be close to $2 billion Doug McCuistion, who heads the Mars exploration program at NASA headquarters, said significant work lies ahead and the space agency will revisit the mission's progress in January.
Meanwhile, "our intent is to keep our eye on the ball and keep pressing" for a 2009 liftoff, McCuistion told reporters in a conference call.
The Mars Science Lab is designed to roam the Martian plains and study rocks to determine whether the environment could support microbial life. It will carry a suite of powerful instruments that can probe rocks and soil in finer detail than previous missions including a laser that can zap boulders from a distance.
Scientists expect the six-wheel, SUV-size rover to build on the successes of twin rovers, which have uncovered geologic evidence of ancient water on the planet, and the Phoenix lander, which recently confirmed the presence of ice at its Martian north pole landing site.
Developing such a scientifically capable spacecraft has proven to be a challenge for engineers at the NASA's Jet Propulsion Laboratory, which manages the mission. Earlier this year, engineers had to redesign the craft's heat shield and fix problems with the parachute. The mission's timetable has also been affected by delays in the delivery of motor parts.
In recent public meetings, McCuistion noted that the Mars Science Lab would likely cause "financial collateral damage" to other space missions to pay for cost overruns.
Last week, James Green, who heads NASA's planetary science division, said possible funding sources could come from the Juno Jupiter mission and the lunar Grail and Ladee projects.
A group of scientists that advises NASA on planetary missions called this week for an outside investigation into the Mars Science Lab's financial troubles. The scientists noted that the pricey project was a "poor model for future missions."
--- On the Net: Mars Science Laboratory: http://mars.jpl.nasa.gov/msl/