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ARM astronauts
A NASA illustration shows an astronaut examining an asteroid captured by the Asteroid Redirect Mission. At a meeting last week, some planetary scientists derided ARM as a “stunt.” (credit: NASA)

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To the outside observer, it might seem logical at first that planetary scientists, particularly those whose who study asteroids, would be supporters of NASA’s Asteroid Redirect Mission (ARM) plans. That mission, after all, will shift a small near Earth asteroid (NEA) into an orbit around the Moon to be visited by astronauts. They will return with tens of kilograms of samples of that asteroid, orders of magnitude more than what NASA’s OSIRIS-REx robotic mission will return from the asteroid Bennu in the early 2020s.

Scientists, though, have been wary to buy into ARM. In the past, they have expressed doubts about the scientific benefits of the mission and concerns it might siphon funding from other missions they feel are more scientifically important. At a meeting last week in Washington of the Small Bodies Assessment Group (SBAG), a NASA-chartered advisory group, debate—and criticism—of ARM was front and center.

Updating the ARM options

The middle day of the three-day SBAG meeting last week, July 30, was devoted to ARM and NASA’s broader Asteroid Initiative. NASA officials came in to present updates on the status of the mission and get feedback from SBAG members, while other scientists weighed in on various aspects of the mission.

Muirhead said NASA is still working towards a cost goal for ARM of $1.25 billion, excluding launch, operations, and the later crewed mission.

The details of ARM have not changed much since the agency did a public forum about the mission in March (see “After a year, NASA’s asteroid mission still seeks definition”, The Space Review, March 31, 2014). NASA is currently evaluating two options for the mission: one where the robotic spacecraft redirects an entire small NEA, no more than about 10 meters in diameter, into a distant retrograde orbit around the Moon, and one where the spacecraft grabs a smaller boulder, a few meters across, from a larger asteroid and returns that to lunar orbit. In both cases, astronauts would visit the captured asteroid on a later Space Launch System/Orion mission, likely in the mid-2020s.

Studies of the two options, designated simply A and B, are ongoing, and NASA plans to select one of the options in December, in advance of a mission concept review planned for February 2015. Brian Muirhead, NASA/JPL chief engineer and the pro-project manager for the Asteroid Redirect Robotic Mission, said NASA is still working towards a cost goal for ARM of $1.25 billion. That cost, he said, would cover development of the ARM spacecraft, but not include launch or operations costs, nor would it include the cost of the later crewed mission.

NASA has identified several candidate asteroids for both Option A and B. With the exception of 2009 BD, an asteroid that could be returned to lunar orbit in 2023, the other candidates would not be in lunar orbit until 2025. That would, in turn, mean the crewed mission would not be until the SLS/Orion EM-4 mission, tentatively slated for 2025, said Steve Stich, deputy director of engineering at the Johnson Space Center (JSC).

That crewed mission would feature two four-hour spacewalks by the two-person crew. NASA has already been working on plans to carry those out, including use of a modified Space Shuttle-era pressure suit as the EVA suit for those spacewalks, and techniques to move from the Orion to the captured asteroid to collect samples. That work has included EVA tests in the Neutral Buoyancy Laboratory at JSC to demonstrate some of the tools and techniques needed to perform those spacewalks, said Stephanie Silipa, exploration Eva architecture lead at JSC.

In her talk, Silipa discussed the notional timeline for each of those EVAs, from preparatory work at the beginning of the spacewalk to cleanup activities at the end. The actual scientific work—collecting samples from the captured asteroid—would only take up one hour of the four-hour EVA, given the time needed to move from Orion to the asteroid and back, as well as other set-up and tear-down activities.

That limited science time has raised concerns from the scientific community, who wonder just how useful that limited time would be. “I think those times are maybe a little pessimistic,” Stich said of the one hour currently planned for scientific work. “I suspect we’ll end up with a little more time to get samples.”

A “one-and-done stunt”

That update from NASA did little, though, to ameliorate concerns many SBAG attendees expressed about the utility of ARM. The meeting featured some of the strongest criticism to date of the proposed mission from scientists, some of whom worry that the failure of ARM could adversely affect other small body science work.

“I think that ARM is a one-and-done stunt, and if we get behind this in any way, it’s going to irreparably damage small body exploration,” Binzel warned.

“I think ARM is a stunt,” said Richard Binzel, a professor of planetary sciences at MIT, in a presentation at the SBAG meeting devoted to criticism of the proposed mission. “A stunt kind of gets handed to you at the top, and there’s nothing underneath to support it.” That’s in contrast, he argued, to the process for selecting science missions, which are supported by rigorous science and compelling questions that only a space mission can answer.

He illustrated his concerns with a whimsical slide about a fictional mission titled Far Away Robotic sandCastle Experiment (FARCE): a spacecraft mission that would go and build a sandcastle on another world. The slide got laughs from the audience, but the message Binzel was trying to convey with it was serious. “The moral here is that you can go that route, or, alternatively, you can dig heels your heels in and advocate that everything we do be on a sustainable path with compelling objectives that serve the national interest through broadly developed, prioritized goals.”

FARCE slide
A slide shown by Binzel of his fanciful FARCE mission, part of his presentation critical of ARM.

ARM, in his opinion, is not sustainable. “I think that ARM is a one-and-done stunt, and if we get behind this in any way, it’s going to irreparably damage small body exploration,” he warned.

Others at the meeting expressed the same worries, particularly if ARM does not survive the change in administrations after the 2016 elections. “There are groups of people who believe that ARM is associated with the current White House” and could be cancelled by the next, said Tom Statler of the University of Maryland and Ohio University. “If it so happens that ARM gets pushed aside because it was the product of the previous administration, there is a risk that the rest of asteroid science could be collateral damage simply because, in the minds of most people, ARM equals asteroid stuff.”

Binzel made it clear he did not oppose crewed missions to NEAs in general, only NASA’s plans to send a human mission to an asteroid redirected to lunar orbit by ARM. “The lunar samples were transformative science,” he said of the samples returned by the Apollo missions, because it was an “absolute first.” By contrast, he said, the ARM samples will be “incremental at best” given the large number of meteorites already studied. “I think it’s actually irrational from the human risk [involved] to get a sample. I don’t think you need to risk human lives for this.”

What he proposed as an alternative were crewed missions to NEAs in their native (that is, not redirected by ARM) orbits. This would, he acknowledged, take more time to carry out than ARM, since it would require developing infrastructure in cislunar space to support longer-duration missions to these asteroids, as well as astronomical surveys to identify potential targets with delta-Vs that are potentially not much greater than an ARM mission.

Those capabilities, particularly for long-duration spaceflight, are on “the true path to Mars,” he argued. “It’s going to take patience. It’s going to take time. It may take 20 years” to carry out such a mission, he cautioned. “So be it. I think we should wait, because if we do wait until these two paths converge, then what we have are asteroids as sustainable stepping stones.”

Some other SBAG meeting attendees separately expressed questions about how ARM fit into the long-term plans for human Mars missions. “What the agency has not articulated is how we’re magically go from cislunar space missions of about a month in duration to anything greater,” said Brent Barbee of NASA’s Goddard Space Flight Center. “If this is all you’re going to do in the mid-2020s,” he said of ARM, “then it’s not very credible to talk about humans on Mars in the early to mid 2030s.”

The NAC and Congress weigh in

At the same time that Binzel was giving his arguments against ARM in Washington, the NASA Advisory Council was meeting at the Langley Research Center, where some members discussed their own issues with ARM.

“So you would downselect between the two concepts before you would assess the costs?” Squyres asked about the two current ARM options.

In a presentation to the NAC, Greg Williams, deputy associate administrator in NASA’s Human Exploration and Operations Mission Directorate, gave an overview of NASA’s exploration plans in general, including ARM. He noted, as other NASA officials did at SBAG, plans to select one of the two options for ARM in December.

That schedule raised questions from some on the NAC. “I’m wondering where in here you do a hard-nosed, non-advocate, independent cost estimate for this. Where does that happen?” asked Steve Squyres, the Cornell University planetary scientist who is the chair of the NAC.

Williams responded that such a cost estimate would take place in time for the mission concept review in February of next year. “So you would downselect between the two concepts before you would assess the costs?” Squyres asked. Williams said internal cost estimates would take place for the two options before picking one, but the independent cost estimate would come after that selection. The NAC later recommended that NASA develop those independent cost estimates for the two options before the downselect.

Later in the meeting, some NAC members were harshly critical of the mission. “It really dumbs down NASA,” said retired aerospace executive Tom Young, as reported by Florida Today. “NASA is better than this, in my view.”

After the NAC and SBAG meetings, Rep. Lamar Smith (R-TX), chairman of the House Science Committee and a critic of ARM, weighed in on the ARM discussions that took place at the two meetings. “The NASA Advisory Council warns that NASA ‘runs the risk of squandering precious national resources’ if they move forward with ARM,” he said in a statement released Friday. “For months, the Obama administration has downplayed such criticism. I appreciate the good work of NASA’s technical advisors and encourage the Obama administration to take their recommendations seriously.”

SBAG’s role in ARM

Binzel discussed his concerns about ARM at the SBAG meeting because that group may be tasked to officially weigh in on the mission’s prospects. The version of a NASA authorization bill passed by the House in early June includes a provision calling for a “complete assessment” by SBAG “of how the proposed mission is in the strategic interests of the United States in space exploration.”

The Senate, though, has yet to either take up the House bill or introduce its own; key members of the Senate have not been quite as critical of ARM as their House counterparts. For now, nothing will happen with the bill, as Congress is on recess until early September.

“A lot of people do not feel neutral about this,” Chabot said of ARM.

There are widely varying predictions about the fate of the authorization bill. At the NAC meeting Wednesday, NASA administrator Charles Bolden was pessimistic a bill would make it through Congress this year. “They have talked off and on about an authorization bill, but we don’t see any serious movement there right now,” he said of the Senate. “I am not optimistic that we will get an authorization bill until 2015.”

However, in an interview a few days earlier at the NewSpace 2014 conference in San Jose, California, Rep. Donna Edwards (D-MD), ranking member of the House Science Committee’s space subcommittee, was more optimistic. “I feel confident that the Senate is going to move forward on its authorization,” she said in a July 26 interview there. “I do hope that it’s one of those things that can be done by the end of this year.” She added that a Senate bill would likely mirror many elements of the House bill, but did not specifically discuss the provisions in the House bill dealing with ARM.

The SBAG meeting concluded on Thursday with no specific findings or recommendations about ARM, although SBAG chair Nancy Chabot of the Applied Physics Lab said ARM-related findings were being developed by the SBAG steering committee. Some worried that a lack of consensus could result in findings that could make SBAG appear neutral on the issue, which Chabot acknowledged as the meeting drew to a close. “A lot of people do not feel neutral about this,” she said.

That may be one thing everyone with an opinion about ARM can agree upon.