In Simple Terms
NASA’s Perseverance rover has collected samples from Mars, but getting them back to Earth is difficult, expensive, and still not planned out. NASA will start a fresh review in 2027 to find a workable way to bring them home. Studying the samples could reveal more about Mars and help prepare for future astronauts.
A mission caught between ambition and cost gets a fresh review
NASA is facing a deceptively simple question that requires a complicated series of spaceflight steps: How do you get samples collected by a rover on Mars into laboratories on Earth? For years, Perseverance has been filling sealed tubes with material from the Red Planet’s surface. But collecting the samples does not guarantee they will ever reach scientists. NASA has now launched a new planning effort to revisit the options, after earlier estimates raised concerns about the project’s cost and how long it would take.
The initiative is called the Perseverance Sample Retrieval Architecture, or PSRA. It is not an announcement of a ready-to-launch spacecraft or a final decision on the mission’s design. Instead, it is a process for developing a new strategy to recover the samples collected by the rover and bring them to Earth. The work falls under the broader Mars Sample Return program, known as MSR.
Tiffany Morgan, NASA’s Mars Exploration Program director, presented the initiative during a virtual meeting of the Mars Exploration Program Analysis Group on November 9. Under the announced schedule, the strategy team will begin work in January 2027 and deliver its final report in winter 2027–2028. In other words, the expected outcome at this stage is a set of recommendations and options—not the samples’ immediate return or a settled implementation schedule.
The team will be asked to assess the mission’s proposed requirements, learn from earlier attempts and designs, and examine available capabilities and contracting and implementation options. It is also expected to offer impartial recommendations on how best to retrieve the material Perseverance has collected. The scope matters because it brings engineering, financial, and organizational questions into the same discussion instead of treating them separately.
The word retrieval does not mean the samples are waiting in one easy-to-reach spot. Perseverance has placed sealed tubes at locations on the Martian surface and kept other samples inside the rover. Any workable plan will therefore need to determine how to reach the material, handle the tubes, and transport them from Mars to Earth. The new planning effort still needs to assess which spacecraft would carry out these steps and how the work would be divided among them.
A small sample cache in Jezero Crater
Perseverance landed in Jezero Crater in February 2021. Since then, it has explored the area and selected rocks and other material that may be worth examining. Roughly the size of a car, the rover uses its arm and tools to carefully collect samples and seal them inside tubes. It has deposited some of the tubes on the surface and kept others on board. NASA images show a group of tubes placed in a sample depot known as Three Forks.
Choosing which rocks to collect is not random. The material may preserve a record of ancient conditions on Mars and could help scientists determine whether the planet once had environments with the ingredients needed for life. That possibility does not mean ancient life has been found—or that it is certain to be found. These are questions that require detailed analysis, and laboratories on Earth have a wider range of tools for examining samples than equipment that can be sent to the Martian surface.
For years, NASA and the European Space Agency have planned to return material from Perseverance’s collection so it can be examined with advanced instruments. The scientific value lies not simply in having a rock, but in being able to carry out different analyses, compare the results, and perhaps examine the sample again as laboratory tools improve. If the tubes remain on Mars, the opportunities to study them will depend on the capabilities of robots and equipment that can operate there.
The return effort would connect robotic exploration already underway with a broader program of future research. The rover collects the material and chooses where to place it, but bringing it home requires a system that can work across vast distances in space and handle the samples without damaging them. The plan must also account for identifying what the materials contain and treating them carefully, especially since scientists want to study them without altering their properties or mixing them with other substances.
Why NASA is back at the planning table
The biggest obstacle so far is that earlier estimates have not produced a solution with both an acceptable cost and a workable schedule. Independent reviews produced very high figures. One concept put the project’s cost at about $11 billion and projected that the samples would reach Earth in 2040. NASA judged that scenario too expensive and the wait until then unacceptably long.
In another review, an assessment team concluded that the samples might be returned earlier, by 2035, at a cost of about $8 billion. That scenario lowered the estimated cost and brought the projected return date forward by five years compared with the 2040 estimate, but it was still a multibillion-dollar project. These figures come from earlier assessments; they are not a final budget approved by NASA or a promise that the samples will return in either of those years.
That is where PSRA comes in. The new review is expected to examine why earlier plans stalled and assess the requirements, capabilities, and available options before a path is chosen. Decisions could involve dividing the mission into stages, finding a way to retrieve the tubes, or working out how to launch them and bring them back. But announcing the initiative does not predetermine which design NASA will adopt. Nor does it yet answer how much money could be saved or what return date might be achievable.
Planning is difficult because the mission does not end when the tubes are collected. The plan must link activities on the Martian surface with the systems needed to transport the material to Earth, while ensuring that the different parts of the mission work together. The longer or more complicated the journey, the more questions arise about reliability, resources, and timing. Reviewing the requirements and lessons from earlier work is therefore not a formality. It is an attempt to avoid building a plan that looks compelling on paper but cannot be carried out within realistic cost and schedule limits.
The samples could help prepare for human missions
The value of bringing the material home goes beyond looking for evidence of past life. At a meeting of the Mars Exploration Program Analysis Group, Bruce Jakosky called for human-mission requirements to be included in integrated planning for Mars exploration. Jakosky is associated with the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder and with the Department of Earth and Space Sciences at the University of Washington. His comments drew on recommendations from a workshop organized by Explore Mars, Inc. in May. The workshop report focused on reducing risks to crews and equipment, not just on scientific returns.
Jakosky noted that Martian soil may contain compounds that could harm astronauts if they breathe them in. Perchlorates and chloromethanes are among the substances already identified, and other compounds may also be present but not yet recognized. Fine dust could pose a respiratory hazard, too, and may gradually affect equipment through friction and wear. Learning about the soil’s composition and the properties of its dust before sending people to Mars would help scientists and mission planners assess these dangers instead of discovering them for the first time while a crew is on the surface.
The samples could help answer questions such as: What are the tiny dust particles made of? How do Martian soil and surface materials behave? And how might they affect spacesuit design and wear? The answers could inform choices about protective equipment and help estimate how much exposure crew members might have to airborne material. A limited collection of samples cannot, by itself, represent every location on the planet. The goal is to gather data from suitable places and materials and interpret it in the geological context from which it came.
There is also a planetary-protection question: how to safeguard life on Earth and Mars. Examining the material in advance could help scientists search for signs of life that might exist today and assess whether such life could interact with organisms from Earth. At the same time, transporting material from another world to Earth requires procedures that prevent contamination of the samples and the transfer of unwanted contaminants. The recommendations noted that applying planetary-protection protocols during a robotic mission could provide practical experience for planning later human missions, even if those missions do not use precisely the same procedures.
The benefits are not limited to safety. Information from the samples could give future crews a clearer initial picture of the environment where they will work, helping them carry out tasks effectively and get more scientific value from their missions. Demonstrating the ability to make a round trip to Mars—including reaching and landing on the planet, taking off from its surface, and returning—would also be an important step in building experience for human exploration. That is an additional reason to study the samples, not a replacement for the scientific questions that led to their collection.
China’s plans add a race-against-time element
NASA is also watching China’s progress on Tianwen-3, a mission designed to return samples from Mars. According to information released by the China National Space Administration, the proposed mission includes a lander, an ascent vehicle that would launch from the planet’s surface, a service spacecraft, an orbiter, and an Earth reentry module. This arrangement illustrates why returning samples takes coordination among spacecraft with different jobs, rather than simply sending one probe to collect rocks.
The Chinese mission is expected to begin around 2028, using two heavy-lift Long March-5 rockets. They are planned to launch from the Wenchang Spacecraft Launch Site in Hainan Province, in China’s far south. The mission’s announced goal is to return about 500 grams of Martian material to Earth in 2031. Those dates and quantities are targets in the plan, not evidence that the samples have already arrived or that the mission’s execution is guaranteed.
China’s program gives NASA an additional reason to reassess its own project, but it does not remove the scientific motivation or solve the financial and engineering challenges. China’s progress adds a sense of competition over timing, while NASA still has to show that any option it chooses can be completed within realistic resource limits. Differences in the designs and systems also limit direct comparisons between the missions. The shared challenge is to transport material from the Martian surface to Earth through a series of demanding steps that require precision.
What the next phase needs to settle
The PSRA team’s report will show whether NASA can turn repeated reviews into a plan that can actually be carried out. It should clarify which requirements are truly essential, which capabilities can be used, and which options have the best chance of balancing cost, schedule, and reliability. The team will also need to learn from earlier efforts rather than repeat the assumptions that led to high estimates or distant timelines.
The report will not make the risks disappear. Sending spacecraft to Mars, handling sealed samples, and transporting them to Earth remain challenging. Even if a target date is set, the plan may change if some requirements prove impossible to meet or too expensive for the available resources. The report expected in winter 2027–2028 should therefore be seen as a milestone for making better decisions, not as a predicted date for the samples’ arrival.
The central question is how NASA can preserve the mission’s scientific value without allowing the plan to grow prohibitively expensive or fall further behind schedule. Perseverance’s samples offer a rare chance to study Martian material in Earth laboratories and may deepen our understanding of the planet’s history and the hazards of exploring it. But that opportunity will produce results only if the return journey is planned realistically and every stage is carried out in a way that protects the samples and makes their recovery possible.
The Bottom Line
NASA is launching a new review of how to retrieve Perseverance’s samples, with work beginning in January 2027 and a final report expected in winter 2027–2028. Earlier estimates ranged from about $11 billion and a return in 2040 to $8 billion and a possible return in 2035. The samples could advance research and help identify dust and chemical hazards before astronauts go to Mars. China’s Tianwen-3, which aims to return about 500 grams in 2031 after a planned launch in 2028, adds urgency to the discussion. But NASA has yet to settle on a final route for bringing its samples home.