Space industry devotées will remember a short-lived NASA program called the Asteroid Redirect Mission, or ARM. The goal of the ARM was to send a robotic envoy to a near-Earth asteroid, “collect a multi-ton boulder from its surface,” and place said boulder into orbit around the Moon. From there, astronauts would visit the transplanted space rock, taking samples and hopefully testing technologies that would prove useful on future missions to deeper space destinations. While the program was shuttered in mid-2017, aspects of the ARM remain vital to ongoing industry initiatives—most notably, the advanced solar-electric propulsion (SEP) system which would have propelled the robotic spacecraft into asteroid territory.
As government agencies and private industry alike take steps to increase the human presence off-planet, the development of advanced propulsion systems like SEP are a key factor in the pace of progress. Long-term crewed missions to cislunar habitats or Mars will require novel means of managing momentum and efficient methods of generating thrust.