An undated handout artist's concept made available by NASA on Dec 4, 2012 showing NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or present ability to sustain microbial life, examining a rock on Mars with a set of tools at the end of the rover's arm, which extends about seven feet (two meters). Media Reports on Dec 4, 2012 state that NASA has announced plans for a robust multi-year Mars program, including a new robotic science rover set to launch in 2020. [Photo/CFP]

SAN FRANCISCO - NASA plans to follow-up its Mars rover Curiosity mission with a duplicate rover that could collect and store samples for return to Earth, the agency's lead scientist said on Tuesday.

The new rover will use spare parts and engineering models developed for Curiosity, which is four months into a planned $2.5 billion, two-year mission on Mars to look for habitats that could have supported microbial life.

Replicating the rover's chassis, sky-crane landing system and other gear will enable NASA to cut the cost of the new mission to about $1.5 billion, John Grunsfeld, the US space agency's associate administrator for science, said at the American Geophysical Union conference in San Francisco.

Budget shortfalls forced NASA to pull out of a series of joint missions with Europe, designed to return rock and soil samples from Mars in the 2020s. Europe instead will partner with Russia for the launch vehicle and other equipment that was to have been provided by NASA.

Grunsfeld said NASA will provide a key organics experiment for Europe's ExoMars rover, as well as engineering and mission support under the agency's proposed budget for the year beginning Oct 1, 2013.

Details about what science instruments would be included on the new rover, whether or not it would have a cache for samples, and the landing site have not yet been determined.

NASA plans to set up a team of scientists to refine plans for the rover and issue a solicitation next summer.

The National Academy of Sciences last year ranked a Mars sample return mission as its top priority in planetary science for the next decade.

"The (science) community already has come forward with a very clear message about what the content of the next Mars surface mission should be, and that is to cache the samples that will come back to Earth," said Steve Squyres with Cornell University.

"That's really a necessary part of having this mission," he said.