Apollo Sites from LRO |
Apollo Sites from LRO |
Jul 17 2009, 02:52 PM
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Founder Group: Chairman Posts: 14433 Joined: 8-February 04 Member No.: 1 |
Thought this deserved a new thread- we can't talk about EVERY LRO target in the one thread
I made a mistake in this one - I didn't include the thruster plume guards. My MER/MPF simulation for HiRISE seemed to come out about right - so fingers crossed that this will be there or there abouts as well. Still in a comissioning phase, something of a slant angle - I'd expect approx 1.5m/pixel if it's at the 120km figure mentioned earlier. |
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May 23 2016, 06:34 PM
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Solar System Cartographer Group: Members Posts: 10197 Joined: 5-April 05 From: Canada Member No.: 227 |
I think you are right about topographic maps. We have this problem everywhere on the Moon. Consider the locations of the Ranger 4 and Lunar Orbiter impacts on the lunar far side. When they occurred we knew nothing about farside topography, so the calculations combined the best estimate of trajectory with a spherical moon to predict the impact location. Today we could re-do the analysis with LOLA topography to get a much better idea of the location. But as far as I know the re-analysis has never been done.
For Apollo 12 and other Earthside impacts, obviously they did have better topography to work with, but it was still quite uncertain compared with today's topography - they had not yet had even the late Apollo altimeters. So a re-analysis with LOLA topography would be really useful. The precision in those quotes is unwarranted. Incidentally, if you put those coordinates for Apollo 12 into Quickmap, the position is about 500 m south of the dark streaks I noted. 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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May 23 2016, 07:19 PM
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Junior Member Group: Members Posts: 62 Joined: 30-July 09 Member No.: 4887 |
"APOLLO MISSION 12, TRAJECTORY RECONSTRUCTION AND POSTFLIGHT ANALYSIS VOLUME 1"
An excerpt: "The rev 34 (deorbit) trajectory for the LM was reconstructed from MSFN doppler data from RID (Madrid, 2-way), MIL, ACN (100 observations pre-burn and 159 observations post-burn), 5 SXT shaft angles, 2 SXT trunnion angles, 7 VHF ranging points, and the thrust profile of the deorbit burn obtained from IMU accelerometer data. The converged residual statistics for all of the observations used in the fit are as follows: No. OBS. Station Type Mean Sigma 86 RID MSFN .348 cps 1.404 cps 87 MIL MSFN .235 cps 1.416 cps 86 ACN MSFN .342 cps 1.356 cps 5 CSM SXT Shaft .001 deg .019 deg 2 CSM SXT Trunnion .033 deg .128 deg 7 CSM VHF Range -470 ft 506 ft The accumulated thrust velocities in IMU platform coordinates due to the deorbit burn are: Delta Vx = -188.57 ft/sec Delta Vy = 54.15 ft/sec Delta Vz = -6.21 ft/sec The time of impact is estimated to be 149:55:16.46 GET. The selenographic coordinates of the impact point are: LATITUDE = -3.944 deg LONGITUDE -21.196 deg RADIUS = 5697847 ft Selenographic Orbit Inclination = -14.531 deg Relative Velocity Magnitude = 5517.2 ft/sec Relative Flight Path Angle = 3.717 deg" Two images from the report offer a little more data. The one shows the above mentioned 7 VHF range data points from the CSM to the LM. |
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