NASA Announces ARM Candidate Asteroids, Study Contracts

NASA has found six valid candidates so far in its ongoing hunt to find an asteroid to use for its Asteroid Redirect Mission (ARM) agency officials announced on Thursday.  They also announced the award of 18 system concept study contracts valued at a total of $4.9 million.

The progress update comes roughly one year after the Obama Administration announced plans for ARM, a modification of President Obama’s 2010 directive to send humans to an asteroid by 2025 as the next step in human space exploration.  Instead of sending astronauts to an asteroid, the ARM concept would bring the asteroid to the astronauts.

NASA divides ARM into three phases:  identifying an appropriate asteroid; using a robotic spacecraft to capture the asteroid and nudge it into orbit around the Moon; and sending astronauts aboard an Orion spacecraft to collect and bring back samples of the asteroid.

“We don’t plan to, nor do we want to, stop looking for targets,” said Michele Gates, ARM program director, at Thursday’s press conference that featured panelists in Washington and others from around the globe joining in virtually.  “We actually wouldn’t need to make a final selection of a target until one year before launch.”

Under current plans, the ARM robotic spacecraft is scheduled for launch in 2019. Two mission concepts are being considered.  “Option A” would capture an entire asteroid less than 32 feet (10 meters) in diameter whereas “Option B” would collect a boulder less than 32 feet in diameter off of a large asteroid.  The agency will choose which option to move forward with likely in mid-December, Gates said.

More than 11,000 near-Earth objects have been discovered and approximately 100 are being found monthly, said Paul Chodas, program scientist at NASA’s Near Earth Object Program. “Discovery is not enough,” he added. “We also have to consider characterization—that is learning about the physical properties of the asteroids.”

The asteroid candidates are being categorized as “potential” or “valid”.  Potentials are “the ones that look good roughly and have roughly the right size,” Chodas said, whereas valids are those for which detailed information such as mass and boulders on the surface already have been derived and are “within the capability of the asteroid retrieval vehicle to bring back.”

The list so far is nine potentials for Option A, three of which are valids; and thousands of potentials, but only three valids, for Option B, Chodas said.

The panelists focused on asteroid 2011 MD, a valid candidate for Option A.  “What you need to have is the kind of asteroid orbit that is very similar to Earth’s orbit and 2011 MD is one of those type of asteroids,” said David Tholen, astronomer at the University of Hawaii.

Infrared data from NASA’s Spitzer Space Telescope reveal it is approximately 20 feet (6 meters) in diameter “perhaps resembling … a rubble pile” with a “remarkably low density” according to a NASA press release.  

The asteroid could fit in a home garage or might actually float in a swimming pool, Michael Mommert, a post-doctoral researcher at Northern Arizona University, said at the press conference.

“This is pretty unexpected because traditionally people thought that small asteroids like 2011 MD are just single pieces of rock or single boulders floating in space,” Mommert continued.  The findings from Spitzer were published Thursday in the Astrophysical Journal Letters.

The opportunity to capture 2011 MD would be in 2024, but more observations are needed to find out what the asteroid really looks like. Other candidates include asteroid 2008 HU4, which will pass close enough to Earth in 2016 for better observations of its size, shape and rotation rate, and Bennu, which will get close up shots by NASA’s Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer (OSIRIS-REx) mission in 2018. OSIRIS-REx is a robotic asteroid sample return mission.

At Thursday’s press conference the agency also announced 18 winners of contracts for system concept studies to further refine ARM. Approximately $4.9 million total will be awarded to fund the six-month studies, which will begin in July.  The awards are in five areas:  asteroid capture system, rendezvous sensors, adapting commercial spacecraft for the Asteroid Redirect Vehicle, partnerships for secondary payloads, and potential partnerships to enhance U.S. exploration activities in cis-lunar space in conjunction with the crewed mission.

NASA describes ARM as part of a pathway toward attaining the goal of eventually sending humans to Mars in the 2030s.   The mission is very controversial and has won little support outside of the Obama Administration.  The recently released National Research Council (NRC) report on the future of human space exploration was the latest to cast doubt on its utility as a step toward human exploration of Mars.  The House Science, Space, and Technology Committee will hold a hearing on the NRC study on Wednesday (June 25).

Thursday’s press conference kicked off a two-day public virtual workshop series that celebrated the one-year anniversary of the White House’s Asteroid Grand Challenge to engage the public in the ARM effort.