Two (or more) ways to get samples back from Marsby Jeff Foust
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| “Either of these two options are creating a much more simplified, faster, and less expensive version of the original plans,” Nelson concluded. |
One concept involved a version of the “sky crane” used to land Perseverance and Curiosity. While that technology is proven, it was not considered in earlier designs for MSR because the sample retrieval lander was far larger than those rovers and beyond the design of it. That lander would have required a propulsive landing system instead.
However, efforts to shrink the size of the lander, in particular the Mars Ascent Vehicle (MAV) rocket the lander would carry to launch the collected samples into orbit, made returning to the sky crane architecture feasible. That is what JPL examined in its study over the summer.
“We took advantage of some features and factors and conditions that really did not exist three or four years ago,” said Matt Wallace, director of the planetary science directorate at JPL, at an advisory committee meeting in November, including confidence that the Perseverance rover would be able to return to the lander with the samples. The JPL study, he said, could cut in half earlier projections that MSR would cost $11 billion and could return samples as soon as 2035, versus 2040 of those earlier projections.
The other concept would deliver that sample retrieval lander with what NASA called a commercial “heavy lander,” details of which the agency did not disclose. However, both Blue Origin and SpaceX performed studies for NASA over the summer to examine how concepts they were developing for Artemis, like the Blue Moon and Starship lunar landers, could be applied to MSR.
Nelson said at the briefing that the agency determined the sky crane option would cost between $6.6 billion and $7.7 billion, while the commercial lander option would cost between $5.8 billion and $7.1 billion. Those options would return samples between 2035 and 2039.
“Either of these two options are creating a much more simplified, faster, and less expensive version of the original plans,” he concluded.
Either the sky crane or the commercial vehicle would carry a redesigned sample retrieval lander and MAV. Fox said the changes included replacing solar panels with a radioisotope thermoelectric generator (RTG) that would make the lander’s operations more robust, particularly in dust storm seasons that would degrade the performance of the solar panels.
The revised lander would also replace a European-developed robotic arm to transfer samples from Perseverance into the MAV with one using spare parts from the arm built for Perseverance. That transfer process would also be revised, she said, to simplify backward planetary protection to prevent Martian dust from contaminating Earth. That would allow for a simpler capture and containment system on the ESA-built European Return Orbiter (ERO) that would pick up the sample canister placed in Mars orbit by the MAV and return it to Earth. Both options would retain that ERO, which ESA has continued to develop while NASA studied new approaches to MSR.
“The main difference is in the landing mechanism,” she said of the two options.
NASA, though, is not rushing to decide which of those two architectures, sky crane or commercial lander, should be used. Nelson and Fox said the agency planned to spend the next 18 months studying the two options while refining other elements of the new architecture.
| “I think it was a responsible thing to do not to hand the new administration just one alternative if they want to have Mars Sample Return,” Nelson said, “which I can’t imagine that they don’t.” |
Fox said the goal is to get both options to a preliminary design review, including changes to the sky crane approach to accommodate a lander about 20% heavier than the rovers it previously delivered to the Martian surface. “It’s almost the normal engineering that we would do to get it up to the preliminary design review level of maturity,” she said.
Doing so will require additional funding. NASA had belatedly requested $200 million for MSR in its fiscal year 2025 budget proposal, but Nelson said in the call that the agency now believes it needs at least $300 million to keep the revised approach on track.
“A bottom line of $300 million is what the Congress ought to consider,” he said. “If they want to get this thing back on a direct return earlier, they’re going to have to put more money into it, even more than $300 million.”
A Senate spending bill last year would have provided NASA with the $200 million it sought for MSR, although a House version directed NASA to spend at least $650 million on the effort. NASA, like the rest of the federal government, is operating under a continuing resolution that keep it at 2024 levels until mid-March.
NASA make the announcement less than two weeks before Donald Trump takes office. Nelson, who will depart the agency at that time, said he had not spoken with the incoming administration’s transition team on the topic, deferring to the “formal transition apparatus” for such discussions. However, he argued it made sense to provide the incoming administration with some flexibility on how to carry out MSR.
“I think it was a responsible thing to do not to hand the new administration just one alternative if they want to have Mars Sample Return,” he said, “which I can’t imagine that they don’t.”
 Rocket Lab pitched NASA on its own end-to-end architecture for MSR using the company’s capabilities in spacecraft, rockets, and other technologies. (credit: Rocket Lab) |
“Lean into commercial capability”
Some in industry, though, don’t like either option handed to the Trump Administration on MSR. Among them is Rocket Lab, one of the companies that received an MSR study from NASA. That study, which was not publicly announced until early October, four months after the other awards, focused on a vertically integrated end-to-end system for picking up the samples and returning them to Earth.
“We think we’re the organization that can bring these Mars samples home faster and cheaper,” said Richard French, vice president of business development and strategy for space systems at Rocket Lab, in an interview after the NASA announcement. “Our architecture, as proposed to NASA, was to bring samples back for less than $4 billion and as early as 2031.”
The company provided a few details about its proposal after NASA outlined its MSR plans last week. Its architecture involved using the company’s expertise in spacecraft and launch vehicles to send to Mars a small lander to retrieve the samples from Perseverance and then launch them into orbit, where another Rocket Lab-built spacecraft would have returned them to Earth. Both missions, along with a separate spacecraft to serve as a telecommunications relay, would launch on Rocket Lab’s Neutron rocket under development.
| “If NASA wants to show leadership, it’s to lean into commercial capability and be bold and compete,” French argued. |
The company argued that it had, or was gaining, experience in various areas for the technologies needed for MSR, from constructing the ESCAPADE Mars smallsat mission for NASA to work on Victus Haze, a responsive space mission for the US Space Force that will involve proximity operations in Earth orbit.
French said that the company heard little from NASA after it submitted its study in the fall. “It was pretty frustrating,” he said. “We received very little to no feedback on our inputs.”
Rocket Lab wants the incoming administration to reconsider the approach NASA laid out and instead open up MSR to a wider competition. “If NASA wants to show leadership, it’s to lean into commercial capability and be bold and compete,” he argued. “We’re pretty hopeful with what the new administration is going to bring and how they respond to this set of recommendations.”
The pace of NASA’s approach to MSR is frustrating others, like the advocacy group The Planetary Society. “We remain concerned that NASA is again delaying a decision on the program, committing only to additional concept studies,” it said in a statement a day after the NASA briefing. “It has been more than two years since NASA paused work on MSR. It is time to commit to a path forward to ensure the return of the samples already being collected by the Perseverance rover.”
The organization did not endorse a specific approach to MSR, be it sky crane, commercial lander, or something like Rocket Lab’s architecture, but called on the Trump Administration to “expedite a decision on a path forward” on it.
At the briefing, Nelson faced questions about the perception that NASA was losing to China in a “race” to return Mars samples. Chinese plans call for launching a sample return mission called Tianwen-3 as soon as 2028 that could return samples in 2031, four or more years before MSR.
Tianwen-3 would be what some have called a “grab ‘n’ go” mission, collecting samples in the immediate vicinity of the lander. That simplifies the technical approach, but doesn’t provide the same degrees of science as MSR, where scientists have spent years curating a set of samples with Perseverance that they believe can provide greater insights into the past habitability of Mars.
“They’re just going to have a mission to grab and go,” Nelson said at last week’s briefing, rejecting the idea that there is a race between NASA and China on returning Mars samples. “That does not give you the comprehensive look for the science community. So, you cannot compare the two missions.”
Scientists, meanwhile, want to get samples Perseverance has collected back as soon as possible, showing little preference for one option over another. At a talk at the AIAA SciTech Forum the day before the NASA announcement, JPL director Laurie Leshin described the scientific interest in those samples, describing one in particular that showed characteristics that she argued would, in a terrestrial rock, be biosignatures of past life.
“That sample is now in the belly of Perseverance, waiting to come home and for us to tear apart in our labs and answer this question about life on Mars,” she said. “Our job is to go get it.”
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