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Enhanced Gravity Tractor Technique for Planetary DefenseGiven sufficient warning time, Earth-impacting asteroids and comets can be deflected with a variety of different "slow push/pull" techniques. The gravity tractor is one technique that uses the gravitational attraction of a rendezvous spacecraft to the impactor and a low-thrust, high-efficiency propulsion system to provide a gradual velocity change and alter its trajectory. An innovation to this technique, known as the Enhanced Gravity Tractor (EGT), uses mass collected in-situ to augment the mass of the spacecraft, thereby greatly increasing the gravitational force between the objects. The collected material can be a single boulder, multiple boulders, regolith or a combination of different sources. The collected mass would likely range from tens to hundreds of metric tons depending on the size of the impactor and warning time available. Depending on the propulsion system's capability and the mass collected, the EGT approach can reduce the deflection times by a factor of 10 to 50 or more, thus reducing the deflection times of several decades to years or less and overcoming the main criticism of the traditional gravity tractor approach. Additionally, multiple spacecraft can orbit the target in formation to provide the necessary velocity change and further reduce the time needed by the EGT technique to divert hazardous asteroids and comets. The robotic segment of NASA's Asteroid Redirect Mission (ARM) will collect a multi-ton boulder from the surface of a large Near-Earth Asteroid (NEA) and will provide the first ever demonstration of the EGT technique and validate one method of collecting in-situ mass on an asteroid of hazardous size.
Document ID
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Mazanek, Daniel D.
(NASA Langley Research Center Hampton, VA, United States)
Reeves, David M.
(NASA Langley Research Center Hampton, VA, United States)
Hopkins, Joshua B.
(Lockheed Martin Space Systems Co. Denver, CO, United States)
Wade, Darren W.
(Lockheed Martin Space Systems Co. Denver, CO, United States)
Tantardini, Marco
Shen, Haijun
(Analytical Mechanics Associates, Inc. Hampton, VA, United States)
Date Acquired
June 17, 2015
Publication Date
April 13, 2015
Subject Category
Spacecraft Design, Testing And Performance
Report/Patent Number
Meeting Information
Meeting: IAA Planetary Defense Conference
Location: Frascati, Roma
Country: United States
Start Date: April 13, 2015
End Date: April 17, 2015
Sponsors: International Academy of Astronautics
Funding Number(s)
WBS: WBS 220933.01.04
Distribution Limits
Public Use Permitted.
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