Monday, April 16, 2001

STS-38 (Atlantis)

 1990-097A


The STS-38 mission was a classified military satellite deployment mission. Of all the STS military flights, this one is possibly the most mysterious.

The OMS-1 burn occurred at an altitude of around 120 km. It probably had a magnitude of 30-35 m/s based on the duration. The angle is unknown, but plausible solutions are to keep the angle or the perigee constant. If the angle is constant (dVx = 30-35, dVz = 0) the orbit is 16-27 x 164-169 km. If the perigee is constant (dVx=17-20, dVx=25-29) the orbit is 73 x 162-170 km. If the apogee is constant the perigee is implausibly high. The ET reentered in the Indian Ocean at 28.5S 84.9E, similar to other non-direct-ascent flights, and most likely the perigee was on the low side: I adopt 20 x 165 km as a plausible post-MECO orbit.

The Shuttle made an RCS and an OMS burn to raise the orbit to 263 x 272 km, and presumably this was the orbit from which payload deployment occurred (unless the OMS was a post-deploy separation burn, but it seems a bit large for this).

The AFP-658 payload was deployed on Nov 16. On Nov 17, the perigee was lowered to 222 km, either for Earth observations or to optimize landing opportunities. Landing was on Nov 20.


STS-38 
 

DateTimeEventOrbit  

1990 Jun 8   Tow to VAB 
1990 Jun 9   ET mate  VAB 
1990 Jun 18   Rollout  LC39A 
1990 Aug 8   Rollback to outside VAB 
1990 Aug 9   Rollback to VAB  VAB/3 
1990 Aug 15  Demate  VAB/3 
1990 Aug 16   Tow to OPF  OPF/2 
1990 Oct 2   Tow to VAB  VAB/3 
1990 Oct 4   ET mate  VAB/3 
1990 Oct 12   Rollout  LC39A 
1990 Nov 15  2348:15  Launch from LC39A 
 2350:18  SRB sep 
 2356:44  MECO 
 2357:02  ET sep  86.29 20 x 165 x 28.45 
 2358:45  OMS-1 (75s) 30-35m/s??  
1990 Nov 16  0000:07  OMS-1 CO  87.44 73 x 221 x 28.45  
1990 Nov 16  0025:48  OMS-2 (103s) 40m/s?  
 0027:21  OMS-2 CO 
 0122:23  PLBD open 
 0041   88.89 215 x 223 x 28.47 
 0100   88.87 214 x 223 x 28.47 
 0335  At perigee 28S 47E 
 0425At apogee 26N 125W 
 0430?  RCS burn 
 0500 89.36 217 x 267 x 28.47 
 0528:23  OMS-3 30s burn 
 0528:53  OMS-3 CO 
 0656?  AFP-658 deployed 
 0716  RCS sep? 
 0948   89.87 263 x 272 x 28.46 
 2322   89.88 264 x 272 x 28.46 
1990 Nov 17  0437?  PROWLER deploy 
 0456?  RCS sep? 
 1249   89.80 260 x 269 x 28.47 
 2119:45  OMS-4 20s
 2120:05  OMS-4 CO 
 2120   89.39 222 x 266 x 28.47 
1998 Nov 18  0718   89.38 221 x 265 x 28.47 
 2134   89.35 220 x 264 x 28.47 
1990 Nov 19  1448   89.34 220 x 263 x 28.48 
1990 Nov 19  2035Landing waved off
1990 Nov 20  0147   89.32 219 x 262 x 28.48 
1990 Nov 20  1811   89.31 219 x 261 x 28.47 
 1916:46  PLBD closed 
 2046:15  OMS DO 1:55 70m/s 
 2048:09  OMS DO CO 
 2111:52  Entry 
 2142:42  Landed KSC RW33 
 2142:52  NGTD 
 2143:41  Wheels stop 
1990 Nov 21 0130Tow to OPF/2 

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