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NASA is looking to simplify a multispacecraft campaign to return samples from Mars while also preserving its partnership with the European Space Agency, which is developing an orbiter (pictured), to fly the samples from Mars to Earth.
NASA is aiming to complete reviews by year-end of 11 proposals from inside and outside the agency to cut costs and speed up the return of samples collected by the ongoing Perseverance rover mission on Mars.
“We think we’re going to be able to come forward with a plan,” Jeff Gramling, director of the Mars Sample Return (MSR) Program at NASA headquarters, told a Mars Exploration Program Analysis Group (MEPAG) meeting on Nov. 6. “Some interesting things have come out through these studies, and I think we’re going to be able to help the [MSR] architecture . . . that hopefully results in our cost estimates coming down.
- A smaller Mars Ascent Vehicle is proposed
- Recommendation is expected by year-end
“I am optimistic, but let’s keep in mind the fundamental complexity of the first roundtrip mission to the surface of another planet is never going to be easy,” he added.
Returning a cache of scientifically selected rock, regolith and atmospheric samples from Mars could reveal whether life ever existed on another planet besides Earth, as well as provide insights into the evolution of the Solar System. The MSR program has consistently been the top goal of the U.S. National Academies of Sciences, Engineering and Medicine, whose decadal surveys identify the most important scientific questions in planetary science and other disciplines.
“For half a century, NASA has engaged in a systematic effort to determine the early history of Mars, assess its biological potential and understand the formation and evolution of habitable worlds, including our own planet,” said Lindsay Hays, NASA senior scientist for Mars exploration. “All of this is building to where we are with MSR.”
NASA Administrator Bill Nelson decided to look for options to the agency’s flagship MSR campaign after a pair of independent studies determined the multilaunch, multispacecraft program would cost up to $11 billion and likely take seven years longer than planned for the collection to be returned to Earth.
“The value of this science is high, regardless of whatever changes may be happening to schedule and architecture,” Hays said at the MEPAG meeting. “These samples will answer key questions about the geological and climatological history of Mars and whether life could have developed there.”
The baseline MSR plan was to launch a spacecraft in 2028 that would land near the Perseverance Mars rover, which has been collecting samples since 2021. Thirty collection tubes would be placed into a canister, launched into Mars orbit, picked up by a second spacecraft, flown back to Earth and released for a parachute landing in the Utah desert in 2033. Independent assessments determined NASA’s estimated $6-7 billion mission costs were $4-5 billion short, and its schedule was unrealistic.
The agency posted a solicitation in April for alternative MSR ideas and received 48 proposals. It selected Aerojet Rocketdyne, Blue Origin, Lockheed Martin, Northrop Grumman, Quantum Space, SpaceX, Whittinghill Aerospace and later Rocket Lab to conduct 90-day studies, which were received Oct. 15. The agency also commissioned studies from the Jet Propulsion Laboratory, the Johns Hopkins University Applied Research Laboratory (APL) and a joint assessment by NASA field centers.
“We basically left the scope wide open,” Gramling said at the MEPAG meeting. “People were able to study the entire mission or particular elements of the mission. We put a pretty forward-leaning schedule in place because we’re trying to get to agency decisions by the end of the calendar year.”
The design studies ended up in three categories:
• End-to-end mission architecture options.
• Viability of developing a smaller, less expensive Mars Ascent Vehicle (MAV).
• A proposal to fly samples to cislunar space, which opens more options for their return to Earth.
The studies are being assessed by a seven-member MSR Strategy Review Team, composed of scientists, technical experts and program managers, with support for cost and schedule estimates by a panel of NASA and outside consultants.
The team will not recommend specific partners, and it is free to evaluate benefits represented in the whole span of studies. “They can put together the architecture they think gives us the best chance of returning samples to Earth before 2040 and/or cost less than the $11 billion architecture,” Gramling said. “It doesn’t have to be any of the studies as proposed.”
The European Space Agency’s Earth Return Orbiter (ERO) likely will remain an anchor component of a revised mission architecture, with a potential launch still on track for 2028.
In a handful of studies summarized during the MEPAG meeting, the MSR’s baseline, two-stage, solid-fuel MAV emerged as a primary candidate for change, along with the system to land it on Mars. A few studies propose using NASA’s sky crane system, which previously landed the Perseverance and Curiosity rovers on Mars, to deliver a smaller—and possibly liquid-fueled—MAV.
The APL, which partnered with NASA’s Wallops Flight Facility, proposed a Mars Integrated Launch System derived from legacy and ongoing missile and sounding rocket programs. “We approached this study not as scaling down a large launch vehicle, but [rather] as starting with a small-missile system and then adapting it for the Mars environment,” Doug Eng, technical lead for the APL/Wallops study, said at the MEPAG meeting.
The APL’s Mars Integrated Launch System is a combination Mars ascent vehicle and launch platform that includes a two-stage, solid-rocket motor launch vehicle housed in a launch platform that doubles as a protective shell during liftoff from Earth, atmospheric entry and landing on Mars and Mars surface operations. The platform would then be elevated for liftoff from Mars, allowing the ascent vehicle to hot-fire and put the sample canister into Mars orbit.
“It will enable NASA the ability to move to a lower-cost, heritage lander system approach,” Eng said. “That is the linchpin in getting the cost savings down by a large scale.”
The APL design can return the 30 higher-priority samples aboard the Perseverance rover, rather than the 10-sample cache deposited on the Martian surface as a backup option. “The approach reduced the mass and size considerably from the reference concept,” Eng said. “With proper funding, the samples could be returned in the mid-2030s, depending on how NASA moves forward with this.”
NASA’s JPL team proposes to replace the program’s baseline Capture, Containment and Return System (CCRS) with a simpler spacecraft, use the proven sky crane technology to land a smaller Sample Retrieval Lander and fly the samples back to cislunar space. The lander would be powered by a radioisotope thermoelectric generator, which provides electrical power by converting the heat generated by the decay of plutonium-238.
“It’s a more benign thermal environment for the systems on the lander, and it reduces the challenges of a compressed surface mission, since we now have that nuclear power source,” said Matt Wallace, the JPL planetary science director.
The JPL study, which also supports return of 30 samples, estimates the collection could be back on Earth as early as 2036 at a cost of roughly half the projected $11 billion baseline mission. “This gets us back in the range of decadal-class missions . . . and fiscal year budget requirements that support a broad planetary portfolio,” Wallace said.
“We took advantage of some features, factors and conditions that really did not exist three or four years ago, starting with Perseverance itself,” he continued. “In the 2020-21 time frame, we had not landed the vehicle and started our surface campaign. Today, we’re two-thirds through, and the vehicle is exceptionally healthy, with all redundant systems operational.”
The health of the rover allowed JPL to eliminate backup plans for fetch helicopters and other vehicles to retrieve the cache that will be loaded aboard the ascent vehicle for launch into Mars orbit. The JPL also looks to leverage capabilities in development for NASA’s Artemis Moon program for the MSR campaign. “There are multiple ways to return from lunar orbit,” Wallace said.
Quantum Space, co-founded by Ben Reed, a 22-year NASA veteran with expertise in NASA Hubble Space Telescope repair and robotic spacecraft servicing, also proposes a cislunar stop for the Mars samples, along with a lighter-weight, simpler CCRS and a new Anchor Leg Space Vehicle (ALSV) to send the collection back to Earth.
Under Quantam’s plan, ESA’s return orbiter, the ERO, would release the volleyball-size sample container into a distant retrograde lunar orbit, where it would be detected, tracked and captured by the ALSV. The container, housed in an Earth Entry System (EES), would then be released to target a much smaller landing zone. Being in a highly elliptical Earth orbit on release—rather than an Earth flyby—reduces the size of the error ellipse by about 560 times over the baseline plan, Reed noted.
“An ASLV could launch either before or after ERO is captured into lunar orbit,” he added. “The dynamics in distant retrograde lunar orbit are very slow, and so that allows for a very methodical, very orderly rendezvous.”
The cislunar return also offers schedule flexibility. “We could hold on to the sample canister, essentially indefinitely,” Reed said. “The delta V requirements for station-keeping [in distant retrograde lunar orbit] are extremely small. We could wait for astronauts to come get it. We could wait for a winged body to fly them onto a runway.”
Quantum’s proposal leverages the agency’s work on the proposed crewed asteroid-retrieval mission and maintains the agency’s baseline CCRS and EES elements for the Mars sample return plan.
L3Harris Technologies vetted 52 options for single- and two-stage MAVs in search of configurations that reduced mass, cost, development schedule and mission complexity, or some combination of those. It also looked at how the lander might change as a result.
The company concluded that a single-stage Mars launch vehicle using a pressure-fed, bi-propellant propulsion system is the best option, particularly one fueled by low-temperature propellants, said Britton Reynolds, senior specialist at the company’s Aerojet Rocketdyne Advanced Propulsion & Technology division.
The MSR review team’s recommendation is to be presented to senior NASA leaders, including Nelson, before year-end. “Hopefully, the administrator will approve the recommended architecture,” Gramling said. “That would be followed by an agency acquisition strategy in the spring.”
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