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| ID No : | 141 Edit | Title: | A Gravitational Tractor for Towing Asteroids |
| Summary / Review : |
Regarding an asteroid on a collision course with Earth, the authors propose sending out a spacecraft with a significant mass to just hover over the asteroid in a spot whereby the spacecraft's mass will be enough to gravitationally nudge the asteroid over time to modify its trajectory sufficiently so that it is no longer a threat to collide with Earth.
For this to work, the asteroid must be small enough and detected long enough before impact. The authors present the equations for a quantitative analysis, and a couple of examples. For example, if a 200 meter wide asteroid appears on an impact trajectory, then a 20 ton spacecraft with 400 kg of propellant could sufficiently deflect it over a period of 20 years. (What would be the cost of managing that program over 20 years?) With nuclear electric propulsion, an additional 5 tons of fuel could deliver it to an asteroid with a delta-v of 15 km/sec. Qualitative comparisons to other methods is covered in a cursory way. In my (the reviewer's) opinion, it's an analysis that needed to be done but it still seems to be of questionable economical competitiveness to other methods, and also is not applicable to asteroids larger than 200 meters width or perhaps heavier metallic asteroids. If the spacecraft fails for any reason over its 20 year mission, then better have a good Plan B ready for quick launch. -MP |
| Author(s) : |
Lu, Edward T., [NASA Johnson Space Center] Love, Stanley G., [NASA Johnson Space Center] |
| Publication Type : | Web = resource available on the web |
| Publication Date: | 2005 |
| Pages : | 3 pages and 1 figure |
| # of References : | 6 |
| Copyright By : | public domain? |
| Category(s) : |
Environment / Asteroid impact |
| Web URL : | No known web URL exists. If you know of one, please Add Comment below. |
| PERMANENT code(s) : | L |
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(Explanation of the last 3 rows above) |
In the row above, there are up to 4 possibilities: U = URL you can click on to get a copy instantly from another source on the internet, or request it from that source D = Downloadable from PERMANENT (such as because no other URL known...) L = LAN copy, PERMANENT has a digital copy but not downloadable from our website P = Paper copy in the PERMANENT office Typically, only 0 to 3 methods are available. |
| Submitted by : | Sam Fraser and Mark Evan Prado |
| Comments: |
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