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Satellites Collide in First-Ever Mid-Space Crash
In sci.space.policy message
, Fri, 13 Feb 2009 11:46:23, John Schilling posted: Assuming the input data, i.e. the SpaceTrack elsets, is good enough for the job. I guess that published data is given to a predefined number of significant figures and the individual uncertainties of each number are not given. The raw material should be more useful than the published material. If better tracking data would help, ISTM that it could be done using measurements from simple satellite-borne radars. Satellites fitted with GPS or similar should know the time and their position rather accurately, by fitting a track constrained by the laws of motion to individual GPS readings. Give them an omni/multi- directional radar (by that, I mean one without a scanning "dish"; it just shouts and listens) with a range if possible of maybe tens of kilometres or more; fairly frequently, returns will "appear" on its "screen", come closer, and move away. It should report the time and distance of each closest approach. That will usually be identifiable as matching, to within the accuracy expected, a known object tracked from the ground; the data will be able to refine the current knowledge of the course of the object. Reporting other times and distances would indicate the relative speed. For unknown objects, the data means that it was at a certain distance from a known point at a known time, and had a particular approximate radar size. It might be possible to discern that a set of the "unknown" readings refer to one object, which then becomes a known object. XP SAA,SSP -- (c) John Stockton, nr London, UK. Turnpike v6.05 MIME. Web URL:http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms & links; Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc. No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News. |
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