SEPT. 8, 2014
Every two years, NASA reviews its long-running scientific missions — currently, the rovers trundling across Mars, the Cassini spacecraft exploring Saturn, and four others — to determine whether they are justifying their cost.
Last week, NASA presented the findings of the most recent review, conducted by a panel of outside experts, to the planetary science subcommittee of the NASA Advisory Council, which provides guidance to the agency’s management.
All seven will continue, assuming NASA can find the money to pay for them.
In particular, Cassini is to continue orbiting Saturn for three more years, making detailed measurements of the ringed planet’s gravitational and magnetic fields. The Curiosity rover is to continue searching for organic molecules in the Martian rocks — though the panel sharply criticized the rover’s mission team, saying its extension proposal “lacked scientific focus and detail” and placed too much emphasis on driving across the terrain rather than stopping to study the rocks.
Two of Saturn’s moons, Titan and Rhea, as seen from the Cassini spacecraft. Credit NASA/JPL-Caltech, via Space Science Institute, via Associated Press
Still, “all extended missions were rated higher than ‘good,’ some after adjustments to scope, as it was recognized that they continue to add important new data and observations for our understanding of solar system bodies and processes,” the review panel concluded.
Supporters of NASA’s planetary program seemed happy. “I think fundamentally we were excited that every mission was given the go-ahead to go on,” said Casey Dreier, the director of advocacy at the Planetary Society, a nonprofit organization that promotes space exploration. “I think that was the biggest takeaway.”
This year, the financial calculus for the review appeared more complex than usual, because Curiosity ended its two-year primary mission in June. Its costs now come out of the budget set aside for extended missions, and that led to speculation that agency officials might turn off Cassini to fit within fiscal constraints.
The Obama administration has proposed deep cuts to the planetary science portion of NASA the last few years, and Congress has partly restored the cuts each year.
The extensions, which would cost $200 million a year, or about 15 percent of NASA’s planetary science budget, still hinge on whether enough money is available. Congress has yet to pass a budget for fiscal year 2015, which begins next month.
“If we do not end up with sufficient funds, NASA will revisit the senior review findings and make the necessary programmatic decisions across our portfolio,” said William P. Knopf, the lead program executive for mission operations in the planetary science division.
A subcommittee of the House Committee on Science, Space and Technology will hold a hearing about the planetary science program Wednesday.
Cassini, which has been in orbit around Saturn for a decade, was the only mission to receive an “excellent” rating from the panel. It was also the only mission to receive a three-year extension, long enough to conduct all of the planned science.
“And best of all, we know now we will live out the full promise of one extraordinary mission,” Carolyn C. Porco, the head of Cassini’s imaging team, wrote on Twitter. “Happy tears in the eyes.”
In 2017, fuel for the maneuvering thrusters will run out, and the spacecraft will be sent on a dive into Saturn.
In giving a “very good/good” grade to the extension proposal for the $2.5 billion Curiosity mission, the panel was especially displeased that John P. Grotzinger, the project scientist, did not present the extension proposal in person, leaving it to a deputy.
“This left the panel with the impression that the team felt they were too big to fail and that simply having someone show up would suffice,” the panel wrote. Dr. Grotzinger said in an interview that he had been scheduled to give a talk about Mars on the day the panel met, and, after consulting with NASA officials, decided not to cancel the talk. “I like to honor my existing professional commitments, especially when they involve outreach,” he said.
He said the team was making the requested revisions. “The review panel was asking us to do more drilling and less driving, and we’re going to do that,” Dr. Grotzinger said.
Curiosity, by coincidence, has just arrived at the destination to begin its main scientific investigation, the base of a three-mile-high mountain in the middle of Gale Crater. By examining the layers of rock as it drives up the mountain, planetary scientists hope to extract the climate history of early Mars when it was warmer and wetter.
The Curiosity team will hold a news conference on Thursday to present its latest findings.
Ranking above Curiosity was the older Opportunity rover, which received an “excellent/very good” rating, allowing it to continue driving to a large deposit of clays. Clay minerals form in aqueous environments that are not acidic, promising sites that could have once been hospitable to life.
The Opportunity rover just had its memory erased and reformatted last Thursday, eliminating the 0.7 percent that had gone bad over the past decade. The rover has had several computer glitches in recent months.
The other missions under review were the Lunar Reconnaissance Orbiter, the Mars Reconnaissance Orbiter, the Mars Odyssey orbiter and the Mars Express orbiter. (Mars Express is a European Space Agency spacecraft, but NASA helps operate two of the of the instruments.)
NASA/Lunar Reconnaissance Orbiter
NASA/Mars Reconnaissance Orbiter
ESA/Mars Express orbiter
The next two years will be busy for NASA’s robotic probes. A new spacecraft, Maven, will arrive at Mars this month to look for clues why Mars long ago dried out and turned cold.
Next July, the New Horizons spacecraft will zip past Pluto for the first close-up look at it; in 2016, another spacecraft, Juno, will arrive at Jupiter to study its interior.
After 2017, however, the pipeline slows. An ambitious mission to study Europa, a moon of Jupiter with an ocean beneath its outer layer of ice and signs of plate tectonics, is not expected to launch until the 2020s.
But Mr. Dreier, of the Planetary Society, said he was optimistic. “We’ve stemmed the bleeding and we’re making a strong case for why planetary is important,” he said. “It’s one of the few parts of NASA that really does explore.”
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