LAS VEGAS — Companies selected by NASA to study alternative approaches to Mars Sample Return (MSR) have offered glimpses of their work that range from tweaking one component to overhauling the entire architecture.
NASA selected seven companies in June for 90-day studies, valued at up to $1.5 million each, to examine different concepts that could reduce the cost or improve the schedule for MSR. NASA requested the studies in April after concluding that its current plans for returning samples collected by the Perseverance rover would cost up to $11 billion and not bring the samples back until 2040.
“That architecture, we know, is too expensive. NASA has asked the industry how we can improve this,” said Jim Green, former NASA chief scientist, during a panel at the AIAA ASCEND conference here July 30 that featured three of the companies selected for those awards. Neither the companies nor NASA had released details about their studies beyond the titles of their proposals selected by the agency in June.
Some are looking at ways to revise the Mars Ascent Vehicle (MAV), the rocket that will be delivered to the surface of Mars by a lander that will then launch the samples collected by Perseverance into orbit. NASA, in its request for proposals, highlighted the MAV as a specific area of interest to the agency.
The MAV, as currently designed, is a two-stage rocket using solid motors that is about three meters tall. “We’re going to study how to best optimize going smaller,” said David McGrath, senior fellow at Northrop Grumman, about his company’s study.
That includes, he said, ways to improve the design of the interstage section between the two stages that includes attitude control systems to reduce the vehicle’s mass. “Our path forward is to take all of our knowledge of all of these systems and our heritage products and blend that into a size range where we think the mission will be affordable,” he said, but did not offer an estimate of the mass reduction he is targeting.
Quantum Space, a startup developing spacecraft that can operate in cislunar space, is focused on another element of MSR, the final return of samples to Earth. Ben Reed, co-founder and chief innovation officer of the company, said their study is looking at ways to simplify the Earth Return Orbiter (ERO), the ESA-developed spacecraft that will pick up the sample canister, known as the OS, placed in Mars orbit by the MAV and carry it back to Earth.
The study, he said, is “leveraging the investments we have made in cislunar capabilities to allow ERO to only have to bring the OS, the sample canister, back to lunar orbit.” That canister would then be picked up by a version of his company’s Ranger spacecraft for an “anchor leg” back to Earth.
That could simplify the design of both the ERO as well as the OS. He cited a case where the sample canister, rather than sent on an Earth entry trajectory to make a hard landing in the Utah desert, would instead be transferred to a spaceplane to return to Earth on a runway, subjected to far lower g-forces. “If we can reduce the g-loading on the sample canister colliding with the surface of Utah,” he said, “the sample canister can get lighter and everything upstream gets easier and better.”
Other studies are looking more broadly at the overall MSR architecture. That is what Lockheed Martin is doing, said Beau Bierhaus, principal research scientist at Lockheed Martin Space, making use of the company’s decades of experience developing Mars and other solar system missions and previous studies of MSR that date back to the 1970s.
One focus will be reducing complexity, he said. Past NASA flagship planetary missions typically have had no more than two elements, an orbiter and lander. MSR, he noted, has up to nine, depending on how an element is defined. “Complexity doesn’t scale linearly by the number of elements,” he said. “Each of these things is co-dependent, co-mingled, and there are ripple effects between them, so the complexity scales non-linearly.”
He did not discuss specifics of Lockheed Martin’s approach, but said it will be guided by several principles, from a focus on key mission requirements to “ruthless” mass control and balancing performance versus cost risks. “We have an opportunity to look across the whole program and think about what heritage elements can be applied and where it makes sense to bring in new technology.”
A fourth company on the panel that did not receive a NASA study is also pitching major changes to the MSR architecture. Ben Donahue of Boeing Exploration Systems said his company has been looking at a concept that would replace the current architecture with a single large lander that would carry a large MAV to launch the samples directly back to Earth. That lander would be launched on a Space Launch System Block 2 rocket.
“The SLS is the right rocket for this mission,” he said, allowing it to carry a lander weighing 23 metric tons that includes a MAV with high-performance liquid-propellant engines that can launch the samples directly back to Earth, bypassing the ERO. “You eliminate a lot of complexity and you use available technology.”
However, Boeing was not among the companies awarded NASA MSR study contracts. Donahue confirmed after the panel that the company submitted a proposal that was not selected.
The studies, which got underway earlier in July, are scheduled to be delivered to NASA in October. The agency will use them, along with separate studies by the Jet Propulsion Laboratory, Applied Physics Laboratory and a group of NASA centers, to see whether and how those concepts can be used to improve the current architecture.
“The results of the studies will inform them what in the architecture could change, what needs to be done,” Green said. Given the wide range of different approaches being considered, some worry it may be difficult to compare or even combine them, although McGrath noted that his company is sharing its work on the MAV with both Lockheed Martin and JPL to inform their own architecture studies.
“It’s a complicated problem,” Green said.
