NASA is that much closer to snatching an asteroid after the robotic half of its two-part Asteroid Redirect Mission (ARM) passed a key program review. The mission to retrieve an asteroid and move it into lunar orbit for study can now proceed to the next phase of design and development ahead of a planned launch in late 2021.

NASA's manned and unmanned mission to move an asteroid into lunar or cislunar orbit isn't just a cosmic rock collecting trip. The space agency regards it as a major demonstration of the technology and methods that may one day allow it to send astronauts to Mars.

The first robotic phase of the mission will demonstrate the capabilities of a number of key technologies, such as an advanced, high-power, high-throughput solar-electric propulsion system, the ability to carry out autonomous high-speed proximity operations near an asteroid, and the capability of touching down on one.

In addition, NASA hopes to try out advanced robotic systems for grappling with an asteroid and a gravity "tractor beam" technique that uses the mass of a spacecraft to steer a large object in space.

ARM will test advanced solar-electric propulsion systems(Credit: NASA)

NASA says that the target for the robotic phase won't be selected until 2020, but that it will be a near-Earth asteroid similar to asteroid 2008 EV – a primitive carbonaceous asteroid that may be rich in volatiles, water, and organic compounds. It's hoped that ARM will be able to recover core samples of such an asteroid that will not only reveal more about the origin of the Solar System, but also the commercial viability of asteroid mining.

The Key Decision Point-B review was carried out in July and approved on August 15. It's the latest in a series of development milestones leading to the mission liftoff. In this case, the milestone has to do with mission content, costs, and schedules for phase B of the project. The objective is to provide a baseline mission for risk, cost, and scheduling analysis for an independent review.

As part of the advancement to the next stage, NASA will be inviting government, private, and international participants to help in developing the robotic phase of the mission and selecting payloads. NASA says that it will provide spacecraft integration services, power, data storage, and payload telemetry. In addition, an ARM Investigation Team will provide technical expertise for the next three to five years for both the manned and unmanned phases of the mission.

Based on the most recent reviews, NASA has pushed back the launch date to December 2021 and the budget has been increased to US$1.4 billion for the prelaunch phase of the mission. The manned mission, which is pencilled in for 2026, is still in the concept phase.

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