1985-010A
51-C was the first classified mission. No details of the flight were given between ET separation and entry interface. It was thought that both OMS-1 and OMS-2 burns were made, although the mission events list does not include an OMS-1.
If there was an OMS-1, we may conjecture magnitudes similar to other OMS-1/2 burn pairs at around 55-75m/s; I give 4 cases below labelled A to E. The ET impacted further west than on any other mission and so we can assume a lower ET trajectory; case A is not a bad fit to the available data, although the ET impact zone may indicate an even larger OMS-1 burn such as case E.
Available orbital data also shows that an 11m/s OMS-3 burn was made, presumably following payload deployment. AWST reported deployment around 1200 UTC on Jan 25, but the orbital data suggests the OMS-3 burn came at southbound equator crossing around 0656 UTC, with a corresponding deployment at 0645 UTC and IUS SRM-1 burn at northbound equator crossing at 0740 UTC. If the AWST report of 16hr MET deployment is correct, the OMS burn was made before deployment, and the corresponding northbound equator crossing IUS burn is at 1215 UTC with deployment at 1120 UTC. It is then puzzling that there is no evidence of a sep burn.
| STS 51-C mission events | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1984 Dec 21 | Roll to VAB/1 | ||
| 1984 Dec 21 | ET mate | ||
| 1985 Jan 5 | Rollout | LC39A | |
| 1985 Jan 24 | 1950:00 | Launch from LC39A | |
| 1952:07 | SRB sep | ||
| 1958:32 | MECO | ||
| 1958:49 | ET sep | ||
| A (Assume 75m/s OMS-1, 75m/s OMS-2) | 86.07 1 x 157 x 28.5 | ||
| B (Assume 65m/s OMS-1, 75m/s OMS-2) | 86.40 21 x 169 x 28.5 | ||
| C (Assume 55m/s OMS-1, 75m/s OMS-2) | 86.73 38 x 185 x 28.5 | ||
| D (Assume 65m/s OMS-1, 65m/s OMS-2) | 86.73 43 x 181 x 28.5 | ||
| E (Assume 80m/s OMS-1, 75m/s OMS-2) | 86.07 -10 x 152 x 28.5 | ||
| 2000 | OMS-1 (?) | ||
| (Assume 65m/s OMS-2) | 88.93 114 x 328 x 28.5 | ||
| (Assume 75m/s OMS-2) | 88.69 81 x 328 x 28.5 | ||
| 2017 | ET apogee (case A) | ||
| 2000:46 | OMS-2 | 91.18 327 x 337 x 28.5 | |
| 2003:47 | OMS-2 CO | ||
| 2036 | ET breakup at 69km | ||
| 2220:48 | PLBD open | ||
| 1985 Jan 25 | 0004 | 91.23 332 x 337 x 28.5 | |
| 0515 | 91.33 336 x 342 x 28.5 | ||
| 0635 | probable USA-8 deploy | ||
| 0651:56 | OMS-3, sep? | 91.64 334 x 375 x 28.5 | |
| 0652:19 | OMS-3 CO | ||
| 0740 | IUS burn, eq crossing N | ||
| 1120 | Alternate USA-8 deploy (AWST) | ||
| 1215 | Alternate IUS burn (AWST) | ||
| 1985 Jan 27 | 0010 | 91.66 335 x 376 x 28.5 | |
| 1744:06 | PLBD closed | ||
| 2016:00 | OMS DO | 88.40 29 x 360 x 28.5 | |
| 2019:13 | OMS DO CO | ||
| 2052:29 | Entry | ||
| 2123:23 | Landed RW15 KSC | ||
| 2123:35 | NGTD | ||
| 2124:15 | Wheels stop | ||
| 1985 Jan 28 | 0250 | Tow to OPF | |
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