CAPE CANAVERAL, Fla. — NASA intends to include an in-situ resource utilization (ISRU) experiment on its new Mars rover that would pull carbon dioxide from the planet’s atmosphere, remove dust and other contaminants and prepare the gas for chemical processing into oxygen.
Depending on what scientists propose for the Mars 2020 rover’s instrument package, a solicitation that closes in January, the ISRU technology demonstration also could include actual oxygen production.
“Our primary focus, at least for this demonstration, is separation [of carbon dioxide] because that’s absolutely essential to test and know that we can pull that off” on Mars, said James Reuther, deputy associate administrator of programs in NASA’s Space Technology Mission Directorate.
The space agency is interested in small, low-power, highly efficient machines that could handle Mars’ variable pressure and temperatures, dust levels, atmospheric conditions and seasonal changes. One flight-certified prototype already exists. The Mars ISRU Precursor (MIP) was planned for NASA’s 2001 Mars Surveyor Lander, but the mission was canceled.
“MIP included a very small solid oxide electrolysis device to electrolyze Mars atmosphere carbon dioxide into oxygen. The device is about one-twentieth scale of what is required for Mars 2020 mission,” said planetary scientist Paul Spudis with the Lunar and Planetary Institute in Houston.
“MIP got to a certain level of maturity where we thought we could make it work as a demo,” Reuther said. “It didn’t happen. We certainly understand that technology and in this [announcement of opportunity] that might be the one that actually ends up going forward. But there are several other technologies that we think are more efficient that are out there.”
NASA expects to select the Mars 2020 science instruments in April, though Reuther said because NASA’s human space exploration and technology directorates are paying for the ISRU demo, “we’re pretty confident” one will be aboard. How much mass, volume and power will be allotted to the device will be determined as part of the overall competition, he added.
The Mars 2020 Science Definition Team estimated a full ISRU demonstration, including capturing carbon dioxide and producing oxygen, would cost about $55 million. A device to demonstrate just the carbon dioxide capture would be about $22 million.
“We don’t know enough about the aerosols on the planet to know if [carbon dioxide capture] is going to be an easy task or an impossible task or an extremely long and tedious task. All those questions have to be answered before you can design a machine that will optimize the production of what you want to make,” Spudis said.
“That’s the purpose of doing an ISRU experiment. It’s to get your hands dirty and try to do it in the alien environment and then see, ‘What is it that I haven’t thought of that’s going to come and bite me in butt?’ That’s really the question you’re trying to answer,” he said.
NASA ultimately would like to produce oxygen on Mars so that it could fuel a Mars-launched rocket heading back to Earth.
“Oxidizer is typically the big mass fraction in launch systems. If you can demonstrate that you can make oxygen, that would serve not only Mars sample return, but also ultimately human missions as well,” Spudis said.
“Every pound that you don’t have to launch from the Earth of dumb mass — things like water and air and propellant — means that you can add a pound of intelligent mass — an experiment, a computer, something designed to accomplish some job or give us some capability. So doing ISRU gives you incredible leverage,” he said.
Mars is not the only body beyond Earth NASA is eyeing for an ISRU demonstration. The proposed Regolith and Environment Science and Oxygen and Lunar Volatiles Extraction, or RESOLVE, mission to the Moon, targeted for launch in 2018, is primarily a mission to inventory water, gases and other volatiles in the soil at one of the lunar poles. But the small rover also would include a device to try to extract water by heating some presumably oxygen-rich lunar soil and running hydrogen through it.
“We’ve been looking at ISRU for quite a number of years,” said ISRU chief engineer Gerald Sanders at NASA’s Johnson Space Center in Houston. “Some say if you incorporate ISRU into your architectures, whether it’s the Moon or Mars, you can get significant benefits, in mass reductions and potential long-term cost reductions and risk reductions.”
“The problem is sort of a chicken-and-the-egg: There’s an inherent risk of putting ISRU in the critical path of mission success, so it’s been stated that you need to do demonstrations. That said, a lot of times funding is associated only with things that are in the critical path for human missions. So we’ve been kind of in a Catch-22,” he said.
“The importance of a mission … like RESOLVE or even the Mars 2020 small ISRU demo that we’re talking about having, is that it kind of breaks that cycle. It starts showing that ISRU is potentially practical. … If it pans out, you can start seriously thinking about how you would change your exploration approach,” Sanders said.