KAGUYA lunar explorer (aka SELENE) |
KAGUYA lunar explorer (aka SELENE) |
Jun 6 2007, 08:29 PM
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#101
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Member Group: Members Posts: 370 Joined: 12-September 05 From: France Member No.: 495 |
SELENE has now a nickname : KAGUYA.
http://www.jaxa.jp/topics/2007/06_e.html Edit : And Emily searched for the origin of the name http://www.planetary.org/blog/article/00000996/ |
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Nov 19 2007, 03:08 PM
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#102
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Solar System Cartographer Group: Members Posts: 10175 Joined: 5-April 05 From: Canada Member No.: 227 |
I'm not so sure about the 'frozen orbits'. I could be wrong - I seem to remember being wrong once... - but here, I think this is probably talking about the orbit plane being fixed with respect to the sun, so you have the same surface illumination all the time. Certain inclinations and orbit shapes give just the right combination of gravitational effects that the orbit is always, let's say, 15 degrees from the terminator.
Low lunar orbits are unstable because of the 'lumpy' gravitational field caused by mascons, which in typical low orbits cause the perilune to migrate up and down over time in complex ways - if I understand it correctly, right now, Kaguya's perilune is ascending, but later it will descend until it has to be corrected. The effects of the Earth, the sun and mascons together make life complicated. I don't think this can be 'frozen'. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Nov 19 2007, 03:22 PM
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#103
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
I'd think mascons* are by far the greatest destabilizing factor for such a low orbit (10 km), with Earth and Sun getting progressively more important (and mascons less important) at higher orbits.
* mascons and high mountain peaks, that is. -------------------- |
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