tag:blogger.com,1999:blog-3596550435682943926.post4531127750763382884..comments2024-03-21T17:50:42.377-07:00Comments on Hop's Blog: Catching an AsteroidHop Davidhttp://www.blogger.com/profile/12923433894475072056noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-3596550435682943926.post-91053378800643026232018-07-21T09:34:42.253-07:002018-07-21T09:34:42.253-07:00This is incredible. Thanks so much for putting har...This is incredible. Thanks so much for putting hard figures to a loosely defined concept.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-3596550435682943926.post-20625091164907490502013-04-15T22:57:54.478-07:002013-04-15T22:57:54.478-07:00I think they're pretty comparable in terms of ...I think they're pretty comparable in terms of delta V.<br /><br />A high lunar orbit deeper in the moon's Hill Sphere would be more stable than a rock parked at EML2. It'd stay put in the moon's neighborhood for a long time, no station keeping needed. <br /><br />A rock at EML2 would need minor station keeping. But if PR successfully extracts propellant from a water rich carbonaceious asteroid, EML2 would be a great place for propellant depots. EML1 and EML2 are hubs that can be exploited by 3 body mechanics as described in the online textbook http://www.cds.caltech.edu/~koon/book/KoLoMaRo_DMissionBk.pdf .<br /><br />EML2 moves at the same angular velocity as the moon (a revolution every 27.3 days or so). A natural two body orbit at that distance from the earth would move .94 km/s, but EML2 moves 1.2 km/s. A slight burn would suffice to tear loose from the moon's influence and the rock could either drop towards the moon or fly out to an 1,800,000 km apogee. Using a lunar gravity assist, Farquhar found an 8 day route from low earth orbit to EML2 that takes only 3.4 km/s. Hop Davidhttps://www.blogger.com/profile/12923433894475072056noreply@blogger.comtag:blogger.com,1999:blog-3596550435682943926.post-1772403028048626662013-04-15T22:08:41.440-07:002013-04-15T22:08:41.440-07:00Is your near EML2 orbit comparable to the Keck'...Is your near EML2 orbit comparable to the Keck's suggested 'high lunar orbit'?Mark Dowhttps://www.blogger.com/profile/17864061121760358984noreply@blogger.com