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Post by ka9q on Jan 31, 2012 14:50:38 GMT -4
Hey, does anybody know the inclinations of the lunar orbits used during each Apollo mission? This is surprisingly hard to find, as it's not in Apollo by the Numbers. I'm looking for the lunar orbit inclinations of the CSMs for each mission when the LMs were jettisoned, specifically for Apollos 11 and 16, the two missions that abandoned their LMs in lunar orbit.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Jan 31, 2012 15:34:19 GMT -4
Hey, does anybody know the inclinations of the lunar orbits used during each Apollo mission? That is something I've been curious about as well. I haven't seen that information in any of the resources I've read. |
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raven
Jupiter
That ain't Earth, kiddies.
Posts: 509
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Post by raven on Jan 31, 2012 16:43:00 GMT -4
Page 16 of this PDF of the "Apollo 11 Preliminary Science Report"seems to give the information desired, I think. Perusing this may be helpful for the other mission in question. |
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Post by ka9q on Feb 1, 2012 5:29:26 GMT -4
Page 16 of this PDF of the "Apollo 11 Preliminary Science Report"seems to give the information desired, I think. Yes, it does: 1.25 deg. Thanks! Here's why I ask. Two of the six LM ascent stages that lifted off the moon were abandoned in lunar orbit rather than being intentionally deorbited onto the moon to provide seismic signals: Apollos 11 and 16. 11 probably because no one had thought of it yet, or perhaps because the engineers wanted to conduct a stress test to see what happened when the consumables (mainly cooling water) ran out. This later became useful during the Apollo 13 emergency. 16's Orion was left in orbit because a procedural mistake deprived the ground of the attitude control needed to do the deorbit maneuver. Because lunar orbits are unstable, both LMs eventually struck the surface but we don't know where. But I'm wondering if it may now be possible to discover their craters. LRO has now mapped most of the moon at high resolution, and it has shown us what an LM ascent stage impact crater looks like (about 10m in diameter, slightly elongated because of the low angle of impact). With GRAIL's forthcoming improvements in the moon's gravity model it may even be possible to project the last known state vectors forward to estimate the impact points. But even without those estimates, it could be done with a lot of eyeballing of the LRO pictures to look for the characteristic craters, perhaps confirming that those craters are not present in the LO images of the same area. The impacts could have occurred anywhere in a latitude band defined by the inclination of their lunar orbits, and since A11 has the lower inclination this band would be much smaller and easier to search by eye than that for A16. |
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raven
Jupiter
That ain't Earth, kiddies.
Posts: 509
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Post by raven on Feb 1, 2012 5:41:05 GMT -4
You know what would be probably of use for this? The old blink comparator. By switching rapidly between the restored Lunar Orbiter images and the LRO images of the same locations, we can fairly quickly see if there has been an addition. It would still be a long, tedious process, but perhaps doable. It could also be of interest for cataloguing changes of a more natural origin. |
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Post by gwiz on Feb 1, 2012 6:29:39 GMT -4
Hey, does anybody know the inclinations of the lunar orbits used during each Apollo mission? This is surprisingly hard to find, as it's not in Apollo by the Numbers. I'm looking for the lunar orbit inclinations of the CSMs for each mission when the LMs were jettisoned, specifically for Apollos 11 and 16, the two missions that abandoned their LMs in lunar orbit. The following figures for final LM orbits are from the DRA Table of Space Vehicles. Note the orbits are retrograde, so subtract from 180 deg to get a more familiar number. Apollo 11 178.7 Apollo 12 165.6 Apollo 14 166 Apollo 15 151.28 Apollo 16 169.3 Apollo 17 159.9 |
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Post by Glom on Feb 19, 2012 14:55:40 GMT -4
You know what would be probably of use for this? The old blink comparator. By switching rapidly between the restored Lunar Orbiter images and the LRO images of the same locations, we can fairly quickly see if there has been an addition. It would still be a long, tedious process, but perhaps doable. It could also be of interest for cataloguing changes of a more natural origin. Sounds as tedious as Mike Brown's works to kill Pluto or upgrade the Tube. |
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Post by ka9q on Feb 20, 2012 12:01:15 GMT -4
Hey, there's a long and storied history of people doing that to discover new planets dwarf planets, asteroids or comets, and Brown certainly discovered a few.
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Post by gillianren on Feb 20, 2012 16:49:31 GMT -4
I found Mike Brown's book on the subject fascinating, actually, and not just because I used to live in Altadena and knew the places in town that he was talking about.
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