NASA will look to industry to build the spacecraft bus for the Asteroid Robotic Redirect mission spacecraft (above). Credit: NASA artist’s concept

WASHINGTON — NASA has kicked off a two-step competition for the spacecraft bus to be used for a proposed mission to haul a chunk of an asteroid to lunar space for astronauts to visit later, according to a procurement note posted online Oct. 20.

Those interested in providing the bus, or skeletal structure, for the agency’s proposed Asteroid Redirect Robotic Mission (ARRM) spacecraft can apply for a Phase 1 Conceptual Studies grant from NASA. Bids are due Nov. 16, with awards anticipated in spring 2016.

Only companies that win a Phase 1 contract will be eligible for follow-on funding, NASA said.

“For our Phase 1 contracts we’re planning $1 million per contract,” Brian Muirhead, ARRM program manager at NASA’s Jet Propulsion Laboratory, in Pasadena, California, said in an Oct. 23 conference call. “The period of performance is nominally through the summer of next year, at which time we would plan on issuing the [request for proposals] for the second phase, which is the procurement of the spacecraft.

“All of that is of course contingent on appropriations from Congress that would allow NASA to move forward,” Muirhead added. He did not say how many Phase 1 grants NASA planned to award.

NASA, like the rest of the government, is now operating under a stopgap spending bill that runs out Dec. 11 and maintains 2015 spending levels until then. Perhaps more importantly, Congress has shown little to no enthusiasm to date for funding the mission.

The ARRM aims to lop off a sample roughly 10 meters in diameter from a much larger asteroid and then haul it into lunar orbit for a close up inspection by astronauts. The craft will test out technology NASA believes it needs to mount a crewed Mars mission, including a high-power solar-electric propulsion system and high-power solar arrays. NASA says the robotic spacecraft itself will cost no more than $1.25 billion and launch in December 2020.

NASA’s 2016 budget request included $220 million for efforts associated with ARRM, which is not yet a formal mission. That will not happen until sometime after February 2016, when the mission is slated for its KDP-B review: the program milestone that formally lays out a mission’s requirements and informs its design.

Besides the spacecraft, NASA also hopes to get ARRM’s solar-electric thrusters from industry. In July, the agency’s Glenn Research Center near Cleveland solicited bids for a “Thruster and Power Processing Unit Development for an Advanced Electric Propulsion System Acquisition.”

NASA now has proposals in hand ­— agency officials did not say how many ­— and in spring 2016 plans to “award a contract to a company to build the engineering unit of this flight-type thruster, working closely with the team at Glenn and JPL,” said Andrew Petro, program executive for Solar Electric Propulsion and Small Spacecraft Technology at NASA Headquarters. “The second phase of that contract will be to produce the flight units that will actually go on the ARRM mission.”

NASA has not yet selected a target asteroid for ARRM but uses 2008 EV5, an asteroid measuring about 400 meters around, as a reference target.

The White House proposed ARRM in 2013 to provide a near-term destination for the Orion deep space crew capsule and Space Launch System Congress ordered NASA to build. The plan is for astronauts launched aboard SLS and Orion to visit the captured asteroid in a distant lunar retrograde orbit.

In the Oct. 23 ARRM briefing, Steve Stitch, director of exploration integration and science at NASA’s Johnson Space Center in Houston, said the crewed leg of ARRM will notionally launch in December 2025.

“We’re only going to fly two people because we’re going to utilize a couple of seats to store the suits,” Stich said.

It will take 11 days for SLS and Orion to reach the captured asteroid chunk, said Stich. The crew would remain in the asteroid’s distant lunar retrograde storage orbit for five days and perform two spacewalks to collect asteroid samples using modified space shuttle flights suits enhanced with a thermal protection layer and an Apollo-style life-support backpack.

NASA in September said the first crewed SLS-Orion mission, once planned for 2021, could slip to 2023. The agency has also said the inaugural SLS-Orion crewed mission will not take astronauts to the captured ARRM asteroid.

NASA continues to search for a target for ARRM, although at this point, 2008 EV5 is looking more and more like a finalist, another NASA official said during the Oct. 23 ARRM telecon.

“Right now 2008 EV5 looks like a good candidate for the mission,” Lindley Johnson said.

That is despite the recent discovery of four asteroids that, in terms of size and orbital accessibility, are similar to 2008 EV5.

“In 2015 we have found four objects that are at least 100 meters in size that are in orbits that are accessible, as accessible as 2008 EV5 and therefore could be accessible by the ARRM robotic spacecraft,” Johnson said.

However, the four new finds are passing by Earth either too early or too late for the ARRM spacecraft to reach them if it launches in 2020, as NASA now plans.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.