NASA rescinded a directive Tuesday that would have forced millions of dollars in cuts from the popular Mars rover program, saying the budget reductions had not been cleared with NASA Administrator Michael D. Griffin.
James Green, head of NASA's Planetary Science Division, last week sent a private communication to the Jet Propulsion Laboratory ordering $16 million in cuts to the Mars program, including $4 million in rover operations this year. If those cuts had been implemented, they would have required that at least one of the rovers, probably Spirit, be put in a state of hibernation.
Since Spirit is already curtailing operations for the Martian winter, the order was not expected to pose a major threat to the rover program. But, more ominously, Green's letter, addressed to Fuk Li, head of JPL's Mars Exploration Program, warned that larger cuts might be necessary later.
Green said an additional $8 million might be cut from the rover program and $8 million from the Mars Odyssey mission. The Odyssey has been mapping Mars' surface since 2001.
Green's letter said the cuts were necessary to offset cost overruns in the Mars Science Laboratory mission, scheduled to launch in 2009. The MSL is a much bigger rover than Spirit or Opportunity, and is packed with sophisticated instruments to determine the planet's habitability. The rover will be landed on Mars with a sky crane spacecraft that will lower it on ropes.
The order sent a shudder through the rover operating office at JPL in La Canada Flintridge and through the wider science community that views the rovers as one of NASA's most glittering successes during a time when the manned exploration program has suffered tragedy and delay.
In a statement Tuesday, Griffin said no Mars rover operations would "be suspended or shut down. This means that the Mars Exploration Program will not take any action as a result of the initial letter."
Griffin said budget reviews were continuing within the space agency to find additional money for MSL, a mission that has cost about $1.8 billion, about $100 million over budget.
Although Green has stated publicly that MSL remains on track for a 2009 launch, his communication to JPL appeared to raise doubts about that, saying that additional cuts of $43 million would be needed to make that deadline.
Griffin's statement blamed the cost overruns "in large part" on an underestimate of the design problems connected with building a rover as complex as the MSL, which has cooking ovens and a laser that can zap rocks from a distance.
Other factors include a need for a larger than expected workforce at JPL, as well as the cost of redesigning the heat shield for the rover after the original shield failed in tests.
This incident marks at least the second recent occasion when NASA was forced to reverse itself after trying to cut a program popular with Americans. Last year, Congress ordered NASA to repair the Hubble Space Telescope, despite concerns from Griffin that the repair mission could be dangerous. The repair mission is scheduled for August.