Sunday, July 21, 2019

GRAIL

 2011-046A

DISCOVERY mission, lunar equivalent of GRACE. Gravity Recovery and Interior Laboratory. Managed by JPL, with PI MIT/Maria Zuber. Lockheed Martin/Denver satellites based on XSS-11 bus with Ka-band rangers.

Each satellite is a box 1.1m high 0.95m wide 0.76m deep. Mass is 307 kg wet, 201 kg dry. Launch by Delta II 7920H-10C.

On 2011 Jan 17, GRAIL-A was renamed Ebb and GRAIL-B was renamed Flow.

In operational phase, orbits from 51 to 16 km. In early April at circular phase, minimized solar perturbations and avoided momentum dumps for maximal sensitivity to lunar core parameters. Orbit determined to 20 cm accuracty; determined that 98 percent of lunar gravity variation is due to surface topography rather than deep interior, and distinguished true lunar basins from many postulated but spurious ones.

GRAIL 1 
 
DateTimeEventOrbit  
2011 Sep 10 1308:52.8 Launch by Delta 7920H  CC LC17B 
  99 deg az 
  T+1:20 SRM 1-6 burnout 
  T+1:20? SRM 7-9 on 
  T+2:40? SRM 7-9 out 
  SRM 1-9 sep 
  T+4:23 MECO 
  St 1 sep 
  SES-1 
 1316 T+7:10 SECO-1  167 x 167 x 29.2? 
   155 x 175 x 29.3 
  1 hr coast 
 1414:44 T+1:05:51 SES-2 (TLI) 272s 
 1419:16 T+1:10:23 SECO-2  175? x 1129400? x 29.2?  
 1428:46 T+1:19:53 S2+9:30, Grail-A sep 
 1434  Solar arrays deployed 
   174 x 1108206 x 29.3 
 1436  T+1:28:08 S2+17:45, Grail-B sep C3=-0.70  
   173 x 1109774 x 29.3 
 1442  Solar arrays deployed 
 1508:02 T+1:59:10 SES-3 depletion 
2011 Sep 11  0057  Stage 2 pass EL1:4 
2011 Sep 11  0358  Pass EL1:4 
2011 Sep 12  0009  Stage 2 orbit  1274 x -179292 x 29.3  
2011 Sep 16   A TCM-1 
2011 Sep 17  0730  Stage 2 at 1.5Mkm   
2011 Sep 23   1 Mkm from Earth 
  Coast to Sun-Earth L1 
2011 Sep 30  1043  Pass GSEx 1.2Mkm 
2011 Sep 30   A TCM-2 
2011 Oct 5   B TCM-2 
  Translunar coast 
2011 Nov 1   Stage 2  347.32d 0.879 x 1.055 AU x 0.01 
2011 Nov 21?  TCM B3 
2011 Nov 22  0814  Inside GSEx 1.2Mkm 
2011 Dec 14?  TCM B4 
2011 Dec 25?  TCM B5 
2011 Dec 30  0938  Enter L sphere 
2011 Dec 31 2121  LOI Grail-A 40min 
  burn over S pole, 191 m/s 
 2201  LOI complete 
  11.5 hr insertion orbit 
2012 Jan 1  2205 LOI Grail-B 39min 
 2244  LOI complete 
2012 Jan 2   OPR phase - Orbit Period Reduction 
2012 Feb 6   TSF phase - Transition to Science Formation 
2012 Mar 7 0115  Science phase begins, sep at 80 km 
  Science orbit 25 x 86 km 
2012 Apr 8    55 x 55 k  
2012 Apr 21   Sep at 220 km, Trim to reverse drift 
2012 May 20    20 x 90 km  
2012 May 29   End of primary mission 
2012 May 29   Science instruments off 
2012 May 30   Orbit adjust 
2012 Aug   Science instruments on 
2012 Aug 31   Extended mission 23 km avge  15 x 35 km  
2012 Nov 2?  Orbit  7 x 40 km  
2012 Nov 28   Decommissioning, 40 days  15 x 55 km 
2012 Dec 6   lower orbit, Endgame phase  2 x 40 km  
2012 Dec 14   Science instruments off 
2012 Dec 14   A TCM for impact 
2012 Dec 17  2139  A depletion 4:03 
  Impact 1.7 km/s 1 deg  -8? x 40? x 90 
2012 Dec 17  2228:51  A Impact 75.62N 26.63W 
  Sally K Ride Impact Site 
  on S face of mountain near Goldschmidt Crater 
2019 Jan 1   Stage 2  346.6d 0.877 x 1.054 AU x 0.01 

Payload:

  • Lunar Gravity Ranging System (USO, Ka-band microwave system) (MIT/Zuber)

  • MoonKAM (Ecliptic/UCSD/)

2011-046B

GRAIL 1 
 
DateTimeEventOrbit  
2011 Sep 10 1308:52.8 Launch by Delta 7920H  CC LC17B 
  99 deg az 
  T+1:20 SRM 1-6 burnout 
  T+1:20? SRM 7-9 on 
  T+2:40? SRM 7-9 out 
  SRM 1-9 sep 
  T+4:23 MECO 
  St 1 sep 
  SES-1 
 1316 T+7:10 SECO-1  167 x 167 x 29.2? 
   155 x 175 x 29.3 
  1 hr coast 
 1414:44 T+1:05:51 SES-2 (TLI) 272s 
 1419:16 T+1:10:23 SECO-2  175? x 1129400? x 29.2?  
 1428:46 T+1:19:53 S2+9:30, Grail-A sep 
 1434  Solar arrays deployed 
   174 x 1108206 x 29.3 
 1436  T+1:28:08 S2+17:45, Grail-B sep C3=-0.70  
   173 x 1109774 x 29.3 
 1442  Solar arrays deployed 
 1508:02 T+1:59:10 SES-3 depletion 
2011 Sep 11  0359  Pass EL1:4 
2011 Sep 12  0009  Stage 2 orbit  1274 x -179292 x 29.3  
2011 Sep 16   A TCM-1 
2011 Sep 17  0730  Stage 2 at 1.5Mkm   
2011 Sep 23   1 Mkm from Earth 
2011 Sep 30   A TCM-2 
2011 Sep 30  1150  B pass GSEx=1.2Mkm 
2011 Oct 5   B TCM-2 
  Coast to Sun-Earth L1 
  Translunar coast 
2011 Nov 1   Stage 2  347.32d 0.879 x 1.055 AU x 0.01 
2011 Nov 21?  TCM B3 
2011 Nov 4  0637  B inward of GSEx=1.2Mkm 
2011 Dec 14?  TCM B4 
2011 Dec 25?  TCM B5 
2011 Dec 31  1019  Grail-B in L Sphere 
2011 Dec 31 2121  LOI Grail-A 40min 
  burn over S pole, 191 m/s 
 2201  LOI complete 
  11.5 hr insertion orbit 
2012 Jan 1  2205 LOI Grail-B 39min 
 2244  LOI complete 
2012 Jan 2   OPR phase - Orbit Period Reduction 
2012 Feb 6   TSF phase - Transition to Science Formation 
2012 Mar 7 0115  Science phase begins, sep at 80 km 
  Science orbit 25 x 86 km 
2012 Apr 8    55 x 55 k  
2012 Apr 21   Sep at 220 km, Trim to reverse drift 
2012 May 20    20 x 90 km  
2012 May 29   End of primary mission 
2012 May 29   Science instruments off 
2012 May 30   Orbit adjust 
2012 Aug   Science instruments on 
2012 Aug 31   Extended mission 23 km avge  15 x 35 km  
2012 Nov 2?  Orbit  7 x 40 km  
2012 Nov 28   Decommissioning, 40 days  15 x 55 km 
2012 Dec 6   lower orbit, Endgame phase  2 x 40 km  
2012 Dec 14   Science instruments off 
2012 Dec 14   B TCM for impact 
2012 Dec 17  2139  B depletion 5:07 
  Impact 1.7 km/s 1 deg  -8? x 40? x 90 
2012 Dec 17  2229:21  B Impact 75.62N 26.63W 
  Sally K Ride Impact Site 
  on S face of mountain near Goldschmidt Crater 

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