Asteroid Redirect Mission

The Asteroid Redirect Mission (ARM) was a NASA mission concept announced in 2013 and later cancelled. It was intended to demonstrate technologies for human exploration beyond low Earth orbit while also advancing planetary-defense techniques and solar-electric propulsion. The planned robotic spacecraft, known as the Asteroid Retrieval Robotic Mission (ARRM), would have traveled to a large near-Earth asteroid, surveyed its surface, and used robotic arms, anchoring grippers, and a drill to secure a boulder approximately four meters across. The spacecraft would then have transported the boulder into a stable lunar orbit, specifically a distant retrograde orbit, where it could have been examined by robotic instruments and potentially visited by astronauts using an Orion spacecraft. NASA presented ARM primarily as a precursor to future human missions to Mars and other deep-space destinations. Its solar-electric propulsion system was designed to operate continuously at low thrust, using electricity from large solar arrays to accelerate ionized xenon. Compared with chemical propulsion, this approach could reduce propellant requirements for slow cargo movement and support reusable space-tug concepts in cislunar space. The proposed spacecraft was also intended to test autonomous rendezvous and proximity operations, asteroid characterization, surface anchoring, sample or boulder acquisition, high-power electric propulsion, and advanced communications. The mission evolved from broader asteroid-retrieval studies. Two principal retrieval concepts were examined: one would have enclosed a small free-flying asteroid in a large capture bag, while the other would have extracted a boulder from a larger asteroid. NASA selected the boulder-retrieval approach in March 2015 because it was judged more relevant to technologies for spacecraft servicing, autonomous operations, planetary defense, sampling, and future resource-utilization activities. The near-Earth asteroid 2008 EV5 was used as a planning example, although NASA had not selected a final target before the program was terminated. Other asteroids discussed in studies included Itokawa, Bennu, and Ryugu. ARM faced scientific, engineering, policy, and budgetary criticism. Critics questioned whether retrieving a single boulder would justify the mission's cost or contribute sufficiently to a crewed Mars program, particularly because meteorite samples and asteroid observations were already available. NASA's Advisory Council recommended in 2015 that the agency reconsider the mission and prioritize solar-electric propulsion for a Mars round trip. Nevertheless, design work and technology development continued for several years. In March 2017, the proposed NASA budget called for ARM to be cancelled in favor of the emerging Artemis approach. NASA issued a defunding notice in April and announced a closeout phase on June 13, 2017. Although ARM itself never flew, several technologies associated with the concept continued in NASA development. In particular, high-power solar-electric propulsion was subsequently associated with plans for cislunar infrastructure, including the Power and Propulsion Element of the Lunar Gateway. ARM therefore remains significant as a cancelled mission concept that connected asteroid exploration, planetary defense, reusable space logistics, and NASA's changing strategy for human deep-space exploration.

Ideas related to asteroid retrieval predated ARM by decades. In July 1980, NASA Administrator Robert Frosch testified to Congress about the possibility of bringing an asteroid to Earth, while acknowledging that the concept was not then feasible. A more focused feasibility study was conducted in 2012 by the Keck Institute for Space Studies. NASA subsequently developed the Asteroid Retrieval and Utilization concept into a proposed mission intended to combine robotic asteroid operations with technologies useful for human exploration. NASA introduced the Asteroid Redirect Mission in 2013. The initial architecture envisioned a robotic vehicle visiting a near-Earth asteroid, altering its trajectory or extracting material, and moving the object or a substantial piece of it into lunar orbit. NASA described the mission as part of a flexible pathway toward Mars. The robotic mission was to demonstrate deep-space propulsion, autonomous operations, asteroid characterization, and planetary-defense techniques. A later crewed mission, called the Asteroid Redirect Crewed Mission, would have used Orion to rendezvous with the retrieved object and allow astronauts to collect samples. Two retrieval approaches were studied. Option A proposed enclosing a small, free-flying asteroid in a large capture bag. The bag would have been designed for an object up to roughly eight meters in diameter and with a much larger mass than the boulder ultimately selected for the baseline concept. Option B called for a spacecraft to approach a larger asteroid, stabilize itself near the surface, and use robotic arms and grippers to capture a boulder. NASA selected Option B in March 2015. The approach was considered more relevant to future autonomous rendezvous, docking, surface interaction, sampling, servicing, and planetary-defense activities. The planned robotic vehicle would have used high-power solar-electric propulsion, potentially based on Hall-effect thrusters. Large solar arrays would supply electricity to ionize and accelerate xenon propellant. The system offered low acceleration but could thrust for long periods, making it suitable for moving substantial cargo through deep space with less propellant than a comparable chemical-propulsion architecture. The spacecraft concept also included robotic arms, anchoring equipment, drilling capability, advanced solar arrays, and proposed high-bandwidth laser communications. Its design was discussed as a possible foundation for reusable space tugs operating between Earth orbit, lunar orbit, and future Mars logistics nodes. NASA had not selected a final asteroid target before ARM was cancelled. The near-Earth asteroid 2008 EV5 served as a planning and simulation example, while Itokawa, Bennu, and Ryugu were among other objects discussed in relation to asteroid missions. The intended boulder was small enough that it would not pose a significant impact threat if it returned toward Earth, and placing it in a distant retrograde lunar orbit would provide a stable location for later robotic or crewed examination. The concept attracted criticism from scientists, advisers, and policy commentators. Questions centered on the cost, the scientific value of retrieving a single boulder, the relationship between the mission and Mars exploration, and whether the crewed component was necessary. NASA's Advisory Council recommended in April 2015 that NASA reconsider ARM and focus instead on solar-electric propulsion for a Mars round trip. NASA continued technical development, however, and in January 2016 the Jet Propulsion Laboratory awarded design-study contracts to Lockheed Martin Space Systems, Boeing Phantom Works, Orbital ATK, and Space Systems/Loral. The Italian Space Agency joined a joint study in May 2016. The proposed NASA budget released in March 2017 called for ARM to be cancelled and resources to be redirected toward the Artemis lunar program. The mission received a defunding notice in April 2017, and NASA announced its closeout on June 13 of that year. ARM never reached flight development or launch. Its most durable legacy was the continuation of high-power solar-electric propulsion research and related cislunar logistics concepts, including technology intended for the Lunar Gateway's Power and Propulsion Element.

• 2017

  Mission defunded and closed out

  [1]Asteroid Redirect Missionen.wikipedia.org

  The mission was defunded during the 2018 budget process and formally entered closeout in June.

• 2016

  Industrial design studies begin

  [1]Asteroid Redirect Missionen.wikipedia.org

  NASA commissioned design studies for the solar-electric-propulsion robotic spacecraft.

• 2015

  Boulder-retrieval architecture selected

  [1]Asteroid Redirect Missionen.wikipedia.org

  NASA selected the option involving robotic extraction of a boulder from a larger near-Earth asteroid.

• 2013

  ARM proposed by NASA

  [1]Asteroid Redirect Missionen.wikipedia.org

  NASA proposed ARM as a robotic asteroid-retrieval and deep-space technology mission.

• 2012

  Keck Institute feasibility study

  [1]Asteroid Redirect Missionen.wikipedia.org

  The Keck Institute for Space Studies examined the feasibility of robotic asteroid retrieval and utilization.

• 1980

  Early congressional discussion of asteroid retrieval

  [1]Asteroid Redirect Missionen.wikipedia.org

  NASA Administrator Robert Frosch testified that retrieving an asteroid had been considered but was not feasible with the technology available at the time.

A NASA technology-demonstration and exploration program positioned as a precursor to human Mars missions, a testbed for planetary-defense methods, and an early concept for reusable cislunar logistics.

• Robotic spacecraft mission · 2021

  Asteroid Retrieval Robotic Mission

  The proposed robotic phase of ARM would have rendezvoused with a large near-Earth asteroid, characterized its environment, captured a surface boulder with robotic arms and anchoring grippers, and transported the boulder to a stable lunar orbit. It would also have demonstrated autonomous operations, asteroid-interaction techniques, planetary-defense concepts, advanced solar-electric propulsion, and potentially laser communications.

• Crewed lunar-orbit mission concept

  Asteroid Redirect Crewed Mission

  The proposed crewed follow-on would have used an Orion spacecraft to rendezvous with the retrieved boulder in lunar orbit. Astronauts could have inspected the object and collected samples, although the crewed mission remained a future concept and was never approved as a flown mission.

• Space propulsion technology

  Advanced solar-electric propulsion system

  ARM was designed around high-power solar-electric propulsion, potentially using Hall-effect thrusters supplied by large solar arrays. The system was intended to provide efficient, continuous low-thrust acceleration for deep-space cargo and reusable space-tug applications.

• 2017

  NASA cancels ARM in favor of lunar exploration prioritiesStrategy

  Background

  The proposed 2018 NASA budget called for ARM to lose its funding amid a shift toward the Artemis lunar exploration program.

  Action taken

  NASA issued a defunding notice in April and announced a formal closeout phase on June 13, ending work on the mission as an integrated flight program.

  Aftermath

  Solar-electric propulsion and related technologies continued in other NASA programs, including planned cislunar infrastructure.

  Source

• 2015

  NASA selects the boulder-retrieval optionStrategy

  Background

  NASA had studied both a capture-bag architecture for a small free-flying asteroid and a robotic system for extracting a boulder from a larger asteroid.

  Action taken

  The agency selected the surface-boulder approach, judging it more applicable to autonomous rendezvous, sampling, servicing, and planetary-defense technologies.

  Aftermath

  The selected architecture became the baseline for the proposed Asteroid Retrieval Robotic Mission.

  Source

1. 1Asteroid Redirect Missionen.wikipedia.org