The solar-powered version of NASA’s Curiosity Mars rover that the agency plans to send to the Red Planet in 2020 could wind up finding and storing samples for eventual return to Earth, a panel of agency “Mars czars” said this week.

Speaking at the Humans to Mars Summit in Washington, D.C., three current or former heads of NASA’s Mars Exploration Program said the science-definition team now deciding what instrumentation will ride on the 2020 rover has sample-caching as a top priority, in keeping with the priority set in the current decadal survey of planetary scientists.

“I think we will see, after the science definition team comes back from their consideration on the 2020 mission, an absolutely fabulous array of measurements that need to be made on samples, decision processes on whether we keep those or not, how we keep those,” said James Green, director of the Planetary Science Division at NASA headquarters and acting director of the Mars program.

Budget pressures threw NASA’s plan to work with the European Space Agency on a Mars sample return campaign into disarray in 2011, when the U.S. agency told ESA it would not be able to continue its partnership in Europe’s ExoMars effort. ESA ultimately entered a partnership with Russia on ExoMars, but NASA continued to work with the European agency to salvage what it could.

Once the nuclear-powered Curiosity rover was down and operating on Mars last year, NASA announced that it would build a solar-powered version to launch in 2020. Doug McCuistion, who preceded Green as head of NASA’s Mars Exploration Program, said he directed the Jet Propulsion Laboratory in 2005 to consider the “sky crane” landing technique “the workhorse system for the next 10-20 years.”

“It was very clear that pretty much any science that we could conceive of, and maybe even experimentation technology demonstrations, we could probably do within a one-ton-to-the-surface capability” provided by the sky crane approach, McCuistion said.

That included the ExoMars rovers, he said, making it logical to use the 2020 U.S. rover to carry out the sample-return caching originally considered for the joint missions.

“We knew that along the line one or more of those was going to be rebuilt, whether it was for what began in 2009 or so, which was a joint mission with ESA that everybody combined themselves into a chassis and an entry system looking like MSL [Mars Science Laboratory], or that was an MSL copy, or whether it’s now the 2020 rover,” McCuistion said.

Scott Hubbard, NASA’s first Mars czar, said the capabilities of terrestrial laboratories to analyze Mars samples will far exceed anything that can be accomplished in situ, and will guide the eventual decision on where to land humans.

“You can analyze samples here on Earth by not just a handful of investigators, but by hundreds of investigators, maybe thousands,” said Hubbard, now a professor at Stanford University. “You cannot just use the laboratory that you guessed was the right lab and took to the surface of Mars, but by every conceivable national laboratory on the face of the Earth that will apply for the samples. And you can use instrumentation that, right now, no one can conceive how to shrink it down.”