Timeline for Why do the LRO's orbital elements appear to constantly oscillate - except recently?
Current License: CC BY-SA 3.0
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| Mar 23, 2017 at 6:23 | history | bounty ended | CommunityBot | ||
| Mar 21, 2017 at 7:45 | comment | added | uhoh | Simulations are used to generate simulated delay-doppler-type results and they are iteratively adjusted until they can reproduce measured delay-doppler data. Sometimes spacecraft data (cameras, accelerometers) might also be incorporated, but usually these don't offer enough precision to match the delay-doppler data. The three ground stations of DSN are busy day and night keeping eyes on spacecraft. Here is some cool delay-doppler data from a spacecraft around the moon, but in this case it is passive radar. | |
| Mar 21, 2017 at 7:41 | comment | added | uhoh | Interpolated is not exactly the right word, fitted might be better. Uusually, the only high-precision data we get from spacecraft orbiting other bodies is delay-doppler. A specially coded/modulated signal is transmitted from the Deep Space Network (DSN) to the spacecraft, which rebroadcasts it back to Earth at another frequency, but carefully phase locked to the incoming carrier. The doppler shift and the absolute delay give relative speed and distance with respect to the ground station, but these are not true state vectors wrt the body orbited yet. | |
| Mar 20, 2017 at 16:10 | history | edited | Schlusstein | CC BY-SA 3.0 |
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| Mar 20, 2017 at 10:49 | history | edited | Schlusstein | CC BY-SA 3.0 |
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| Mar 20, 2017 at 4:07 | history | answered | Schlusstein | CC BY-SA 3.0 |