In the last couple of months, NASA has appeared to put a greater emphasis on the role its overall asteroid initiative, including the Asteroid Redirect Mission (ARM), could play in planetary defense. However, in a meeting last week, NASA administrator Charles Bolden appears to play down the role the mission could play in planetary defense or science.
“I don’t like saying we’re going to save the planet, for example,” Bolden said in a meeting of the NASA Advisory Council (NAC) on July 31 in Washington. “At some point, that may be done, but that’s not—we’re not in a position that we should be saying, ‘Fund the asteroid initiative and we’re going to save the planet.'”
He also deemphasized the role of science in the proposed mission to redirect an asteroid into a “distant retrograde” lunar orbit to then be visited by a crewed Orion spacecraft. “We should not be saying that this is going to benefit science. It is not a science mission,” he said. He said that the mission would accomplish some science, including by astronauts bringing back samples of the asteroid, “but it should not be characterized, or we should not try to characterize it, as a major science initiative.” What the asteroid mission will do for planetary science, he concluded, was “peanuts.”
Instead, the asteroid initiative was designed to advance long-term human space exploration in a time when the budget doesn’t exist for human missions to the Moon. “When I weigh the cost benefit of going back to the lunar surface in a limited budget environment, and going to Mars, I would rather take what little money I have upfront and advance the technologies we’re going to need” to do Mars missions, he said. He cited as one example the development of solar electric propulsion, something he said isn’t needed for a human return to the Moon but is useful for Mars and other deep space missions.
That downplaying of the role of the ARM for science or planetary defense aligns with the findings from last month’s meeting of NASA’s Small Bodies Assessment Group (SBAG) in Washington. Referring to the ARM as the ARRM (Asteroid Redirect and Return Mission), the SBAG found it wanting both in science and planetary defense.
“ARRM has been defined as not being a science mission, nor is it a cost effective way to address science goals achievable through sample return,” the SBAG found. “Robotic sample return missions can return higher science value samples by selecting from a larger population of asteroids, and can be accomplished at significantly less cost… Support of ARRM with planetary science resources is not appropriate.”
The SBAG also noted that since the mission would focus on redirecting an object no more than 10 meters across (although there is some discussion of visiting a larger asteroid and plucking a smaller boulder off it), “ARRM has limited relevance to planetary defense.” In addition, the group cited concerns about technical, cost and schedule risks, as well as poorly defined mission objectives.
With regards to schedule, one interesting item came up during the NAC meeting. Previously, NASA had talked about redirecting an asteroid to provide a destination for the first crewed SLS/Orion mission, designated Exploration Mission 2 (EM-2), planned for launch in 2021. One challenge has been, though, finding a target that, even in the most optimistic scenarios for the development of the robotic ARM spacecraft, could be put into te designed distant retrograde orbit by 2021. In a briefing about the initiative at the NAC meeting, NASA’s Michele Gates said “our current concepts are looking at either EM-3 or EM-4″ for the Orion mission to the asteroid. That would likely push out the mission into the mid-2020s, given the expected cadence of at least two years between SLS/Orion flights.