1969-043D
Lunar Module 4 was assigned to the Apollo 10 mission, and nicknamed Snoopy after a comic strip character. Commander was Col. Tom Stafford, USAF, and LMP was Cdr. Gene Cernan, USN.
During preparations for undocking on May 22, the tunnel between the CSM and the LM would not vent properly. To work around this the LM was partially depressurized to 3.5 psi.
On 1969 May 22 Snoopy undocked from Charlie Brown (CSM 106), and fired the DPS in a Descent Orbit Insertion burn, going down to a 15 km altitude flyby of Apollo Landing Site 2, the future Tranquility Base. The LM 4 crew made visual observations and tests of the landing radar. The DPS was fired again in a phasing burn which increased perilune to 22 km. Two hours after the low pass, the descent stage was jettisoned. As this happened, the ascent stage entered a spin as the RCS jets fired in response to faulty data caused by an incorrect switch position. The crisis was soon over and the crew recovered control in only 8 seconds.
The ascent stage's APS engine was fired after jettison, sending Apollo 10 into solar orbit. The exact orbit is not known, but one estimate gives 2 km/s velocity at infinity corresponding to a range of 0.8 to 1.3 AU in extreme heliocentric range, depending on the angle; for most angles the deviation from 1AU is much smaller; an orbit of 0.9 x 1.1 AU is a reasonable guess.
| Snoopy (LM4) | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1969 May 18 | 1649:00 | Launched as cargo on SA-505 | KSC LC39B |
| 2045:24 | Removed from S-4B-505 by CSM-106 | ||
| 1969 May 22 | 1549 | Power up, crew entry | |
| 1747:50 | T+96:58:50 Begin LM depress to 3.5 psi | ||
| 1748:07 | At 3.5 psi | ||
| 1749:46 | At 4.0 psi | ||
| 1751:04 | Repress | ||
| 1751:41 | At 5 psi | ||
| 1900:57 | T+98:11:57 Undocked from CSM 106 | 109 x 114 | |
| 2035:00 | DPS burn, DOI (0:27) | ||
| 2035:28 | DOI CO | 15 x 113 | |
| 2130 | 15 km low pass over Tranquility | ||
| 2147:25 | DPS phasing | 22 x 352 | |
| 2334:17 | T+102:45:17 DS jettison | 21 x 352 | |
| 2334 | RCS burns, AS in spin | ||
| 2334 | AS control recovered | ||
| 2344:01 | APS burn (0:15) | ||
| 2344:16 | APS CO | 21 x 84 | |
| 1969 May 23 | 0034:55 | RCS CSI | |
| 0035:22 | CSI CO | 77 x 87 | |
| 0132:53 | CDH 2s | 78 x 87 | |
| 0211:55 | RCS TPI | 87 x 107 | |
| 0212:12 | TPI CO | 86 x 111 x 178.9 | |
| 0304 | RCS TPF, rendezvous with CSM | ||
| 0311:02 | Docked with CSM 106 | 101 x 111 x 178.8 | |
| 0326 | HO, Crew transferred to CSM 106 | ||
| 0437? | HC | ||
| 0506 | AOS | ||
| 0513:36 | Undocked from CSM 106 | 99 x 114 x 178.8 | |
| 0514 | LM cabin depressurized | ||
| 0515 | 3.0m/s sep from cabin venting | ||
| 0541:02 | APS depletion burn (3:33) 1158m/s | ||
| 0544:29 | 207s pressure depletion decay | |
| 0544:35 | APS shutdown, solar orbit 2.7603 km/s (dV 1132m/s) | 107 x -7559 x 179.1 (MR) | |
| 3.030 km/s? (dV 1402m/s) | |||
| (dV 1169.8, Tab 8.6-IV) | |||
| 4.91 km/s (dV 3282m/s) | 104 x -4095 (MR Tab 6-IV) | ||
| 0545:10 | 248s APS commanded off | ||
| 1019 | At 28078 km from Moon | ||
| 1159 | LM RCS burn 32s 8.4m/s | 290 x -7739 x 179.1 | |
| 1620 | Depart Lunar SOI, R = 66183km | ||
| 1700 | At 68292 km, 1.632 km/s; end of tracking | ||
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