NASA calls for rover instrument proposals, but some resent the space lost to storage of samples for retrieval by an unspecified future mission

Image: NASA/JPL-Caltech

Have rover, need payload. Thats the state of things for NASA, which is planning to launch its next rover to Mars in 2020. The rover has ambitious goals, including searching for signs of habitability and life on the Red Planet, and collecting rock samples to be stored for future return to Earth. Now, NASA is asking scientists to propose instruments that will help the spacecraft accomplish its mission.

The space agency released an announcement of opportunity on September 24 calling for proposals by December 23. Researchers who plan to put an instrument in the hat must file a heads-up about their plans, called a notice of intent, by October 15.

The design of the 2020 rover will hew closely to that of Curiosity, which landed on Mars in August 2012. The new vehicle will have the same basic body, called a chassis, and will use the same sky crane landing system to be lowered onto the surface. But the innards of the rover will be all new, featuring a suite of instruments that move beyond what Curiosity can do.

The instruments must accomplish specific goals for the rover set out in a July report by its Science Definition Team, which disbanded after the report was issued. The goals include scouting for habitable locations and looking for possible signs of past life there, such as microbial fossils and concentrations of organic material. The rover will also be tasked with digging up rock core samples and storing them for future retrieval and return to Earth by a future spacecraft, where they can be studied in laboratories with much more sophisticated instruments than anything that can be sent to Mars.

Because sample storage will take up room inside the rover, however, it wont be able to carry instruments for analyzing dug-up samples on Mars as Curiosity does. Curiosity has flown really high-end instruments to do its measurements on the surface of Mars, says Jack Mustard of Brown University, who chaired the Science Definition Team. What this coming rover will do is arguably a better job of finding materials that are interesting. Its somewhat upgraded in its capabilities to do remote measurements. It doesnt try to do any in situ analysis like Curiositys Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments do.

But that decision has angered some Mars scientists, who say the rover will have to sacrifice too much of its instrument space for caching samples. I think if were going to have a Curiosity duplicate rover in 2020, it should be loaded with instruments to do in situ science, says Robert Zubrin, co-founder and president of the Mars exploration advocacy nonprofit, The Mars Society. This one says its going to have 28 kilograms of science instruments. Curiosity has 80 kilograms. Theyve reduced the science payload by a factor of three in order to have this caching function, which may not have any utility whatsoever. Zubrin says it leaves too much up to chance to have the return of these samples rely on an unspecified mission in the future making a precision rendezvous and landing at the same spot to collect them.

The Science Definition Team members say the 2020 rover will still be able to do significant science, and its important to initiate Mars sample return now. This mission I think will be on par, in terms of what we learn, with Curiosity, and hold the future prospect of being able to learn 10 times more by bringing samples back to Earth. None of us are going looking for Klingons, but wed be thrilled if we could help find a sample that contains microbes, says Scott Murchie at Johns Hopkins Universitys Applied Physics Laboratory, who was a member of the team.

The rovers goal of collecting samples for return follows from the conclusions of the planetary science decadal survey published by the National Research Council in 2011. It combined input from hundreds of scientists to prioritize the various science projects of interest to the planetary science community over the coming decade. Rated above all other goals, including a mission to Jupiters intriguing moon Europa, was the aim to begin the process of returning samples from Mars to Earth.

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Cache and Not Carry: Next Mars Rover to Collect Samples for Return to Earth—Someday