NASA Launches New Plan to Bring Mars Samples Home by 2035

The samples are already waiting

One thing isn't in question: the goods exist. Perseverance, a car-sized rover that touched down in Jezero Crater in February 2021, has spent years drilling select rock specimens. It has stashed sealed tubes inside its body and dropped others onto the Martian surface.

Scientists think those tubes may hold evidence of past life on Mars. NASA and the European Space Agency have spent years planning spacecraft that would collect the rover's pickings — including sniffs of Martian atmosphere — and fly them home for study with lab equipment too heavy to fly to Mars.

Why robots instead of astronauts?

Speaking at the same MEPAG meeting, Bruce Jakosky of the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder argued samples must come back before humans go. He drew on recommendations from a workshop last May organized by Explore Mars, Inc.

That report focused on how Mars Sample Return reduces risk for crewed missions rather than on pure science, Jakosky told Space.com. "The purpose is to understand the risk to astronauts and to hardware," he said.

"The risk includes that from compounds that are present in the soil that are hazardous to astronauts if breathed in," Jakosky said. "This includes perchlorates and chloromethanes that have been identified already, and detection of other species that might be present. It also includes dust that can be breathed in by astronauts and that can affect hardware wear and tear."

His list of reasons to return samples before humans land includes:

• Identify and characterize hazardous chemicals such as perchlorates and chloromethanes to protect astronaut safety
• Characterize fine dust particles that could cause respiratory problems for crews
• Study dust and regolith behavior to inform spacesuit design and wear patterns
• Search in advance for any existing Martian life that could interact with terrestrial life
• Provide early context that boosts astronaut effectiveness and science return on the surface
• Demonstrate a successful round trip to Mars, including entry, descent, landing and surface ascent
• Rehearse planetary protection protocols, making equivalent rules for human missions easier to plan

The China factor

Pressure is also coming from abroad. China's Tianwen-3 Mars Sample Return mission is moving forward, and it's moving fast.

According to the China National Space Administration, the Tianwen-3 probe will carry a lander, an ascender, a service capsule, an orbiter and an Earth reentry module. The mission appears on track to launch around 2028 aboard two Long March-5 heavy-lift rockets from the Wenchang Space Launch Site on Hainan, China's southernmost island province.

China's target: roughly 500 grams of Martian material back on Earth in 2031 — about the weight of a stick of butter. That would be four years before NASA's cheapest projected timeline, and nine years before the 2040 date NASA already rejected as too slow.

For now, NASA's answer is a study team that won't even meet until January 2027. Whether PSRA can close that gap is the open question hanging over the entire program.