For years, NASA’s Perseverance rover has been drilling, sealing and storing pieces of Mars that scientists hope might hold signs of ancient life. The hard part has always been getting them back to Earth. Now NASA is taking another run at that problem.

The agency is starting a new effort called the Perseverance Sample Retrieval Architecture, or PSRA, to come up with a fresh plan for bringing those samples home. Here is what it is, why it matters and why China is part of the story.

What NASA announced

According to Space.com, PSRA was mentioned on November 9 by Tiffany Morgan, director of NASA’s Mars Exploration Program, during a virtual meeting of the Mars Exploration Program Analysis Group, a community forum for Mars scientists.

The goals of PSRA, as described there, are to:

  • Develop impartial recommendations for retrieving the samples collected by Perseverance and delivering them to Earth.
  • Assess the proposed mission requirements.
  • Review lessons learned from earlier plans.
  • Evaluate current capabilities and options for buying or building what is needed.

Morgan said a PSRA strategy team will kick off in January 2027, with a final report due in winter 2027-2028.

Why Mars Sample Return has been so hard

Perseverance landed in Jezero Crater in February 2021. Since then it has collected carefully selected rock, soil and even atmosphere samples, sealing them in tubes. Some were left on the surface in a depot, and others are stored inside the rover.

The challenge is that no spacecraft has ever launched from the surface of Mars and returned to Earth. Bringing the samples back would require landing, collecting the tubes, launching them into Mars orbit, catching them and flying them home.

That complexity has come with sticker shock. Space.com reports that one review put the price at about $11 billion, with samples arriving in 2040, a figure NASA itself considered too costly and too slow. Another assessment found a cheaper path of roughly $8 billion with a return as early as 2035. How PSRA will handle cost is still to be determined.

Why samples matter before humans go

Scientists want the samples to search for possible signs of past life using laboratory equipment far more powerful than anything a rover can carry. But there is another reason too.

At the same meeting, Bruce Jakosky of the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics argued that returning samples could reduce risk for future astronauts. “The purpose is to understand the risk to astronauts and to hardware,” he told Space.com. That includes chemicals like perchlorates already found on Mars, and fine dust that could be breathed in or wear down equipment.

Studying real Martian material would also help with spacesuit design and planetary protection planning, and would demonstrate a full round trip to the Red Planet.

The China factor

There is also a competitive angle. China’s Tianwen-3 mission is designed to bring back about 500 grams of Martian material in 2031. According to the China National Space Administration, as reported by Space.com, it will include a lander, an ascent vehicle, an orbiter and an Earth reentry module, and it appears on track to launch around 2028 on two Long March-5 rockets.

If that timeline holds, China could return Mars samples before NASA, which adds pressure to the new review.

The bottom line

NASA’s samples are already sitting on and inside Perseverance, waiting for a ride home. PSRA is the agency’s latest attempt to find an affordable, realistic way to make that happen. We’ll know much more when the team reports back in late 2027 or early 2028.

Image: 6th Perseverance Rock Sample Malay at Three Forks Sample Depot by NASA/JPL-Caltech via Wikimedia Commons, Public Domain Mark 1.0