WASHINGTON — While the $2.5 billion Mars Science Laboratory has been approved for a two-year mission extension that will cost NASA roughly $115 million, senior scientists warned that the flagship rover is at risk of underachieving, and that its status as crown jewel of the agency’s planetary science division appears to have gone to the mission team’s head.

The Mars Science Laboratory’s Curiosity rover landed on the red planet in August 2012. Equipped with a drill to gather surface samples and spectroscopy equipment to analyze the samples, the rover has collected and analyzed five surface specimens so far and, according to the extended mission proposal just approved by NASA, would analyze another eight over the next two years.

That is “a poor science return for such a large investment in a flagship mission,” a 15-person senior review panel chaired by Clive Neal, a geologist at the University of Notre Dame in South Bend, Indiana, wrote in a report published Sept. 3.

The report also chided John Grotzinger, the lead Curiosity project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, for neglecting to show up in person during a Mars-focused senior review panel meeting in May.

“This left the panel with the impression that the [Curiosity] team felt they were too big to fail,” the senior review panel wrote.

So while NASA endorsed the senior review panel’s recommendation to extend the rover’s mission through September 2016, the agency has also directed the Curiosity team at JPL to “develop a new task plan and get back to us,” William Knopf, a NASA program executive, said during a Sept. 3 meeting of the NASA Advisory Council’s planetary science subcommittee at agency headquarters here.

Knopf would not say exactly how long the JPL team has to turn in a new task plan.

Senior review panels are convened periodically to decide whether it is worth NASA’s while to continue funding missions that have accomplished their primary science objectives. Curiosity got the nod even though the senior review team was not sure whether the flagship rover had completed its primary science mission at all.

“It was unclear from both the proposal and presentation that the Prime Mission science goals [of Curiosity] had been met,” the panel wrote in a report summarizing its nearly five-month-long senior review of ongoing planetary science missions. “In fact, it was unclear what exactly these were.”

NASA accepted the senior review panel’s recommendation to extend all seven missions that were up for review this year. Only two missions, the Lunar Reconnaissance Orbiter and Europe’s Mars Express orbiter, will see notable operational changes as a result of the senior review. Besides Curiosity, the missions that won extensions, and the approximate cost of those extensions, are:

  • The Cassini Saturn orbiter, which arrived at the gas giant in 2004 on a four-year primary mission. The flagship outer planets mission will continue for three years at a cost of roughly $175 million. The mission will end around September 2017, when the orbiter is set to plunge into Saturn’s atmosphere.
  • The Moon-mapping Lunar Reconnaissance Orbiter, which launched on a one-year primary mission in 2009. The senior review panel wanted to turn off three of the orbiter’s seven instruments, but NASA agreed to shut off only the Mini-RF instrument: a synthetic aperture radar. The two-year extension will cost about $40 million.
  • The Mars Exploration Rover Opportunity, which landed in 2004 on a 92-day mission. Opportunity, which outlasted its twin, Spirit, will need about $30 million to rove for another two years.
  • The Analyzer of Space Plasma and Energetic Atoms-3, a partially NASA-funded instrument aboard the European Space Agency’s Mars Express orbiter, which arrived at Mars in 2004 on a primary mission of just under two years. Two more years will cost NASA about $6 million, but the agency is pulling support for the team that calibrates the orbiter’s High Resolution Stereo Camera. NASA accepted the senior review panel’s advice that calibration efforts would be substantially cheaper if done automatically.
  • Mars Odyssey, an orbiter that arrived at Mars in 2001 on a 32-month primary mission. Although the senior review team said the orbiter has actually become more useful to the agency’s heliophysics and human spaceflight divisions, owing to radiation measurements it makes, NASA agreed to a two-year extension costing roughly $25 million. Odyssey is also a telecommunications relay for Opportunity.
  • The Mars Reconnaissance Orbiter, which arrived at Mars in 2006 on a two-year primary mission. The orbiter will get roughly $60 million for two more years of operations.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.