NASA to narrow asteroid retrieval options

MELBOURNE, Fla. — A meeting this week will determine what kind of asteroid astronauts might take a chisel to in a decade or so, if NASA succeeds in capturing such a target for human exploration missions.

Associate NASA Administrator Robert Lightfoot on Tuesday will choose between two options for the robotic spacecraft that would attempt to capture the rock and haul it back near the moon where astronauts could reach it in Orion, the capsule NASA test flew (without a crew) for the first time Dec. 5.

One option for the Asteroid Redirect Mission, or ARM, would capture a small asteroid up to about 32 feet in diameter. The other would pluck a loose boulder from the surface of a larger asteroid.

Key to the decision, Lightfoot said recently at Kennedy Space Center, would be which option best tested technologies and operations that will be needed for an eventual journey to Mars or one of its moons.

"We really think if we can bring this asteroid back into this area around the moon, we'll have plenty of things we can prove, all that will have to be extensible to a mission to Mars at some point," said Lightfoot.

The proposed mission has skeptics in Congress and among scientists, but would give astronauts something interesting to do in Orion after its launch from Kennedy Space Center by the new Space Launch System rocket.

Orion can only fly missions lasting about three weeks, so it can't get to an asteroid in its "native" deep space orbit, a mission Lightfoot said would take two years going out and two in.

"So that's a four-year mission, and we just don't have the systems ready to go do that kind of mission," he said.

Without a lander, moon landings are not an option, and NASA says that would only be a distraction from its long-range goal of reaching Mars by the 2030s.

"For us the focus has got to be extensibility to Mars," Lightfoot said. "And if I'm building systems that are specific to the moon, that's systems I'm not building to get to Mars."

The robotic spacecraft envisioned to capture the asteroid will be powered primarily by solar energy, a technology NASA says will be essential to robotically staging supplies on Mars in advance of a human mission.

So even if the spacecraft whiffs on the asteroid or can't pry off a boulder, the ARM mission could prove out an important system in space.

"That's one of the reasons we love this potential mission," Lightfoot said.

If successful, NASA says the ARM mission also will test techniques that could be used to deflect an asteroid that threatened Earth, offer a sample for science research, and provide valuable operational experience.

The planned mission would fly two astronauts who would perform one or two spacewalks. Orion is designed to carry four, but mass will be reserved for mission-specific equipment, including a kit to repressurize the capsule after spacewalks, and for asteroid samples to be returned.

The timing of a human visit depends on which asteroid ultimately is pursued and when it becomes reachable, probably not before the mid-2020s. That means NASA will probably fly at least one or two flights with a crew before then.

Those flights also would probably be in the vicinity of the moon, which NASA calls its exploration "proving ground" — days farther from home than the International Space Station, but not as risky as trying to send people straight to Mars.

This week's decision will prompt additional study leading up to a more thorough Mission Concept Review in February. That should give the go-ahead to start work on the robotic spacecraft and set a price tag for the asteroid mission, now estimated at $1.2 billion, not including launch vehicles.