Asteroid Redirect Mission
The Asteroid Redirect Mission (ARM), also known as the Asteroid Retrieval and Utilization (ARU) mission and the Asteroid Initiative, is a potential future space mission proposed by NASA. Still in the early stages of planning and development, the spacecraft would rendezvous with a large near-Earth asteroid and use robotic arms with anchoring grippers to retrieve a 4-meter boulder from the asteroid.
The spacecraft will characterize the asteroid and demonstrate at least one planetary defense technique before transporting the boulder to a stable lunar orbit, where it could be further analyzed both by robotic probes and by a future manned mission. If funded, the mission would be launched in December 2020, with the additional objectives to test a number of new capabilities needed for future human expeditions to deep space, including advanced ion thrusters.
The Asteroid Retrieval and Utilization mission, excluding any manned missions to an asteroid which it may enable, was the subject of a feasibility study in 2012 by the Keck Institute for Space Studies. The mission cost was estimated by the Glenn Research Center at about $2.6 billion, of which $105 million was funded in 2014 to mature the concept. NASA Administrator Charles Bolden has stated that: "This mission represents an unprecedented technological feat that will lead to new scientific discoveries and technological capabilities and help protect our home planet." NASA officials emphasized that ARM was intended as one step in the long-term plans to send humans to Mars.
The two options studied to retrieve a small asteroid were Option A and Option B. Option A would deploy a large 15-metre (50 ft) capture bag capable of holding a small asteroid up to 8 m (26 ft) in diameter, and a mass of up to 500 tons. Option B, which was selected in March 2015, would have the vehicle land on a large asteroid and would deploy robotic arms to lift up a boulder up to 4 m (13 ft) in diameter from the surface, transport it and place it into lunar orbit.
The crewed portion to retrieve asteroid samples from the Moon orbit (Orion EM-3) has been criticized as an unnecessary part of the mission, as thousands of meteorites have already been analyzed, and that the technology used to retrieve one boulder does not help develop a crewed mission to Mars.
The NASA Advisory Council suggested in 10 April 2015 that NASA should not carry out its plans for ARM, and suggested instead to develop solar electric propulsion and use it to power a spacecraft on a round-trip flight to Mars.
Additional mission aims include demonstrating planetary defense techniques able to protect the Earth in the future - such as using robotic spacecraft to deflecting potentially hazardous asteroids. Under consideration for deflecting an asteroid are grabbing the asteroid and directly move it, as well as employing gravity tractor techniques after collecting a boulder from its surface.
The mission would also test the performance of advanced solar electric propulsion (ion engines), and broad-band laser communication in space. These new technologies will help send the large amounts of cargo, habitats and propellant to Mars in advance of a human mission to Mars.
|NASA Asteroid Redirect Mission|
The vehicle would land on a large asteroid and grippers on the end of the robotic arms would grasp and secure a boulder from the surface of a large asteroid. The grippers will dig into the boulder and create a strong grip. An integrated drill will be used to provide final anchoring of the boulder to the capture mechanism. Once the boulder is secured, the legs will push off and provide an initial ascent without the use of thrusters.
The advanced ion engine uses 10 times less propellant than equivalent chemical rockets, it can process three times the power of previous designs, and increase efficiency by 50%. It will use the Hall-effect, which provides low acceleration but can fire continuously for many years to thrust a large mass to high speed. Hall effect thrusters trap electrons in a magnetic field and use them to ionize the onboard xenon gas propellant. The magnetic field also generates an electric field that accelerates the charged ions creating an exhaust plume of plasma that pushes the spacecraft forward. The spacecraft concept would have a dry mass of 5.5 tons, and could store up to 13 tons of xenon propellant.
Each thruster system will have a 30- to 50-kilowatt power level, and several thrusters can be combined to increase the power of an SEP spacecraft. This engine, which is scalable to 300 kilowatts and beyond, is being research and developed by Northrop Grumman with Sandia National Laboratories and the University of Michigan. NASA Glenn Research Center is managing the project.
Proposed mission timeline
If funded, the mission would be launched with an Atlas V rocket in December 2020, and returning the boulder to lunar orbit by late 2025. If the Asteroid Redirect Mission and the Space Launch System are both completed on schedule, a manned mission to the asteroid brought to lunar orbit could be launched as early as 2026.
As of June 2014[update] more than 1,000 new near-Earth asteroids have been discovered by various search teams and catalogued by NASA's Near-Earth Object Observation Program. The carbonaceous asteroid chosen for capture by NASA (4 meter diameter, 94 tons ) will have a mass too small to harm the Earth because it would burn up in the atmosphere. Redirecting the asteroid mass to a distant retrograde orbit around the Moon will ensure it will not hit Earth and also leave it in a stable orbit for future studies.
NASA has yet to select a target for ARM, but for planning purposes it is currently using a near Earth asteroid named (341843) 2008 EV5 of about 400 m (1,300 ft) in diameter to pick up a single 4 m (13 ft) boulder from it. The decision on the target asteroid could be deferred to as late as 2019, allowing additional time to find alternative targets.
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- NASA Solar System Exploration, Asteroid Redirect Mission (ARM) (accessed September 30, 2014)
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- NASA 2014 budget proposal on ARU mission. (PDF)
- Incredible Technology: How to Grab an Asteroid and Park It Near Earth, Space.com., 16 April 2014, Miriam Kramer
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- Staff (13 April 2015). "News from the 31st Space Symposium: Bolden Not Concerned About ARM Criticism". Space News. Retrieved 2015-04-15.
- How Will NASA's Asteroid Redirect Mission Help Humans Reach Mars?. NASA, June 27, 2014.
- NASA YouTube video:ARM, 'Option B': Boulder collection from a large asteroid.
- Kathleen C. Laurini and Michele M. Gates, "NASA's Space Exploration Planning: the Asteroid Mission and the Step Wise Path to Mars]", 65th International Astronautical Congress, Toronto, Canada, Sept-Oct. 2014. This paper (and related papers from the 65 IAC) can be found on the NASA page Asteroid Initiative Related Documents (accessed 5 January 2014)
- John Brophy, Fred Culick, Louis Friedman and al. (12 April 2012). "Asteroid Retrieval Feasibility Study" (PDF). Keck Institute for Space Studies, California Institute of Technology, Jet Propulsion Laboratory.
Table 1: Asteroid Mass Scaling (for spherical asteroids). Page 17.
- Advanced Solar Arrays: Powering Exploration. NASA.
- "Hall Thruster Research: Propelling Deep Space Missions". NASA (Space Ref). March 31, 2015. Retrieved 2015-03-31.
- Solar Electric Propulsion (SEP). NASA.
- Blake, Mary (January 31, 2012). "Northrop Grumman Tapped by NASA to Develop Solar Electric Propulsion Flight Concepts for Future Space Missions". Northrop Grumman Corporation. Retrieved 2015-03-31.
|Wikimedia Commons has media related to Asteroid Redirect Mission.|
- Asteroid Initiative Program by NASA
- YouTube videos
- Video: Asteroid Redirect Mission, 'Option A', Capture of an 8m free-flying asteroid.
- Video: Asteroid Redirect Mission, 'Option B', Boulder collection from a large asteroid.
- Video: Asteroid Redirect Mission: Crewed Orion spacecraft rendezvous with ARM in lunar orbit