NASA is contemplating two methods to return its invaluable Mars samples back to Earth; however, the agency will not determine a preferred choice for around 18 months.
Evaluating those samples, which are being gathered by NASA’s Perseverance rover, could uncover a plethora of information about Mars and its past — potentially including insights into whether the Red Planet has ever supported life.
Consequently, NASA is keen to bring the Martian material — approximately 30 sealed tubes the size of cigars that contain rock cores and sediments — back home, and subsequently distribute it to laboratories worldwide. However, accomplishing this goal has turned out to be more challenging and significantly more costly than initially anticipated.
For instance, in July 2020, the total projected expense of the Mars sample return (MSR) initiative — a joint effort between NASA and the European Space Agency (ESA) — was around $3 billion. Yet, just three years later, the expected budget had escalated to between $8 billion and $11 billion. Even with such an expenditure, the samples are unlikely to reach Earth before 2040.
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Nasa has recently found this predicament unacceptable. In April 2024, agency leader Bill Nelson declared that a redesign of the MSR strategy is on the horizon, indicating that NASA will pursue innovative solutions from its research facilities, private sectors, and academic institutions.
A few months afterward, the agency selected 11 MSR proposals from academic and industry teams for additional development. Eight of the private entities received up to $1.5 million each to continue refining their ideas over the upcoming 90 days.
Such efforts have resulted in another accomplishment, which NASA announced during a press briefing this afternoon (Jan. 7): The agency is now concentrating on two potential MSR designs, which differ in how they would deploy hardware on Mars.
The first alternative would utilize a rocket-powered “sky crane,” the system that successfully landed NASA’s Curiosity and Perseverance rovers on Mars back in August 2012 and February 2021, respectively. The second option would depend on private companies to provide the landing mechanism.
Opting for the sky crane would yield an MSR expenditure of $6.6 billion to $7.7 billion, Nelson stated today. The commercial alternative — which NASA chose not to elaborate on due to concerns regarding proprietary technologies and designs — would be slightly less expensive, estimated at $5.8 billion to $7.1 billion.
“Both of these options have resulted in a notably simpler, quicker, and more cost-efficient approach than the initial plan,” Nelson mentioned.
He added that, with the recently revealed overhaul, the samples could potentially land on Earth as soon as 2035, assuming Congress allocates adequate funding. Approximately $300 million may be necessary for MSR research and development in this fiscal year and for each subsequent year, according to Nelson.
Both possibilities would deploy the same hardware on the Martian landscape — a lander equipped with a small rocket known as the Mars Ascent Vehicle (MAV).
The lander will land close to Perseverance, which will move to the more recent spacecraft. The lander will then use a spare robotic arm designed for Perseverance’s mission to grasp the sample tubes and place them inside a canister on the MAV. (Apparently, there is no space in the new design for a helicopter like Ingenuity for sample recovery, which was considered in previous plans.)
The rocket will subsequently launch the samples into Martian orbit, where they will rendezvous with a spacecraft provided by ESA to transport them back to Earth.
In either scenario, the MAV and lander will be less heavy than initially imagined, making the use of a sky crane feasible. (The original MAV/lander concept was too bulky for a sky crane, necessitating a new and untested landing mechanism. Even with the new considerations, the sky crane would need to be about 20% larger than the one that landed Perseverance, agency representatives stated today.)
The lander will also utilize a nuclear energy source — a radioisotope thermoelectric generator (RTG), similar to what Curiosity and Perseverance employed — rather than solar panels as previously planned. The RTG presents two significant benefits, according to Jeff Gramling, NASA’s MSR program director.
“One is that it allows us to operate during dust storm periods. The surface operational timeline is one of the primary factors here, to ensure we have sufficient time to transfer the 30 tubes,” Gramling shared during today’s press briefing.
“The second advantage is that it helps us maintain the warmth of those solid rocket motors on the MAV, which is their preferred state,” he added.
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NASA is investigating both landing strategies — including the in-depth engineering work needed for each — and does not expect to finalize a decision until mid-2026. Given this schedule, the European return orbiter could not launch before 2030, and the lander/MAV would not depart prior to 2031, remarked Nicky Fox, head of NASA’s Science Mission Directorate.
Consequently, Perseverance’s samples may not be the first untouched Martian material to return to Earth. China plans to initiate its own sample-return mission in 2028, which could bring the samples back as early as 2031. However, that mission will gather material from a single location, while Perseverance has been collecting samples from diverse environments, many of which were previously exposed to liquid water in ancient times.
China’s proposed “grab and go” design “does not offer a comprehensive perspective for the scientific community,” Nelson stated today.
“Will individuals suggest there is a competition?” he queried. “Certainly, individuals will think that. But these are two entirely different missions.”