1996-062A
The first Mars Surveyor probe, MGS was sponsored by NASA-OSS and managed by JPL. The spacecraft was built by Lockheed Martin Astronautics' MM Technologies Inc of Denver, and the mission control center was in Denver. It consists of a propulsion module, an equipment module, and a nadir deck with science instruments. Solar arrays carry extra 1-m aerobraking flaps. [53]
The spacecraft carries half of the Mars Observer instrument complement, to recover from the loss of MO in 1993. It has a mass of 1062 kg and was intended to operate for 5 years. The probe would enter an elliptical capture orbit and use aerobraking to circularize at a lower altitude. MGS includes a bipropellant propulsion system with a 596N main engine, using a design derived from Cassini but with a Leros1b LAE.
During the aerobraking phase small RCS burns at apoapsis will maintain correct periapsis altitude.
Launch mass is 1062 kg, with a 598 kg bus and 76 kg science payload, together with 388 kg of fuel. The bus is 1.5 x 1.5 x 3.0 m with a 12 m solar panel array span and a 2m HGA antenna boom. After launch, one solar panel failed to open completely, jammed 20 degrees from the planned position. The planned orbit was adjusted to compensate for a modified aerobraking profile [54]. The initial MGS and PAM-D trajectory was designed to miss Mars (achieved B.T, B.R = -19709, -459279 km per ESASP403-371). On Nov 21 the MGS engine burned to target the spacecraft closer to the planet and in March TCM-2 refined the approach.
In May 1997 MGS went into safemode because of a software problem. It was commanded back into operation later that month.
The first few aerobraking passes forced the problem solar panel into an almost fully open configuration, within one degree of nominal. But on the 15th pass an increase in density bent the panel, and the aerobraking was interrupted while the situation was studied. The new plan was to resume aerobraking at lower force, 0.2 Pa. The slower braking and the interruption would mean that the final sun-synchronous orbit reached would have a different sun angle (9 AM) than the originally planned 2 PM orbit, because of the way the orbital plane precesses with time in the aerobraking orbit. This would cause difficulties for both science and operations, so the revised plan called for another interruption of aerobraking, this time for six months. The 11.6 hour elliptical phasing orbit, chosen to be lower than the 2:1 resonance with Martian rotation that would cause orbital perturbations, would allow the orbit plane to precess so that when aerobraking resumed for a third phase in late 1998, the final orbit reached would be a 2 AM orbit, essentially equivalent to the originally planned one. Mapping would begin in Mar 1999, during northern summer.
Aerobraking resumed one month later in Nov 1997. The Noachis dust storm in Dec 1997 caused ram pressures as high as 0.8 Pa instead of the usual 0.2 Pa at the 121 km standard aerobraking altitude, so perigee was raised slightly for a while.
In Mar 1997 a 4 m/s main engine apogee burn raised perigee from 123 km to 170 km, ending the first aerobraking phase. During the several month Science Phasing Orbit pause, MGS carried out science observations. Aerobraking resumed in Sep 1998.
Mapping began in 1999, but was soon interrupted when the high gain antenna (HGA) ran into problems. One hinge stopped travelling through its full range of motion; it was found that the nominal mapping plan would work through Feb 2000 after which the antenna problem would interfere with operations.
The first trim burn on 1999 May 7 had a problem when the plume was partly blocked by the HGA, reducing burn efficiency and changing the average direction of thrust. The intent had been to put MGS in a repeating orbit with a ground track spacing of 59 km.
In late 2006 MGS' batteries failed due to a software error, and Earth lost contact with the probe on Nov 2.
| MGS | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1996 Nov 7 | 1700:49 | Launch by Delta 7925 | CC LC17A |
| 1701:53 | Solids 1-6 burnout | ||
| 1701:55 | Solids 7-9 tig, 1-6 sep | ||
| 1702:58 | Solids 7-9 burnout | ||
| 1703:01 | Solids 7-9 sep | ||
| 1705:10 | Thor MECO | ||
| 1705:18 | Thor sep | ||
| 1705:24 | Delta burn 1 | ||
| 1705:35 | Fairing sep | ||
| 1710:26 | Delta SECO 1 | 185 x 185 x 28.47 | |
| 1741:31 | Delta burn 2 | ||
| 1743:37 | Delta SECO 2 | 173 x 4720 x 28.5 | |
| 1744 | Spin table spinup to 60 rpm | ||
| 1744:30 | Delta sep | ||
| 1745:08 | PAM-D burn | ||
| 1746:35 | PAM-D TECO | 184 x -97283 x 28.46 | |
| 1751:12 | Yo-yo deploy, despin | ||
| 1751:17 | PAM-D sep | ||
| MGS solar array deploy | |||
| Delta depletion burn | |||
| 1996 Nov 8 | 0246 | Pass EL1:4 | |
| 1996 Nov 12 | 1842? | Pass L1 sphere, solar orbit | |
| 1996 Nov 21 | 1600 | TCM-1, 44s 27m/s | |
| 1997 Mar 20 | 1800 | TCM-2 3.8m/s, 6s (+20s ullage) | |
| 1997 May 8 | 1130 | Safemode | |
| 1997 May 24 | Exit from safemode | ||
| 1997 Aug 22 | Range to Mars 5.04Mkm, 0.245km/d | ||
| 1997 Aug 25 | 1630 | TCM-4, 11s, 0.29m/s | |
| 1977 Aug 29 | Range 3.56M km, approach 0.247Mkm/d | ||
| 1997 Sep 5 | Range 1.56M km, approach 0.249Mkm/day | ||
| 1997 Sep 7 | 2115? | Enter Mars gravisphere | |
| 1997 Sep 9 | Mars SOI sphere (0.6Mkm) | ||
| 1997 Sep 9 | 1445 | Pressurize tanks | |
| 1997 Sep 9 | Range 600000 km | ||
| 1997 Sep 10 | Range 300000 km | ||
| 1997 Sep 12 | 0117:20 | 22m12s MOI burn, 1500 km over N pole | |
| 0139:39 | MOI complete 0.973km/s | 44h59.5m 258 x 54021 x 93.3 | |
| 1997 Sep 16 | 1744 | AB-1 OTM lower peri, 5s, third apoapsis | 150 x 54000 x 93.3 |
| 1997 Sep 17 | 1637 | First atmosphere pass | 150 x 54000 x 93.3 |
| 1997 Sep 18 | 1503 | RCS lower peri | 129 x |
| 1997 Sep 19 | 1328 | Pass 2 | 128 x 53855 x 93.3 |
| 1997 Sep 20? | RCS lower peri? | ||
| 1997 Sep 21 | 1007 | Pass 3 | 121 x 53595 x 93.3 |
| 1997 Sep 23 | 0629 | Atmosphere pass 4 | 121 x 53340 x 93.3 |
| 1997 Sep 24 | 0431 | RCS lower peri | 116 x |
| 1997 Sep 25 | Pass 5 | 116 x 52800? x 93.3 | |
| 1997 Sep 27 | Pass 6 | 116 x 52330 x 93.3 | |
| 1997 Oct 3 | 110 x 48770 x 93.3 | ||
| 1997 Oct 6 | Pass 15 | 121 x | |
| 1997 Oct 11 | Pass, panel problem | ? | |
| 1997 Oct 12 | Raise peri at apo | 173 x 45135 x 93.3, 35hr | |
| 1997 Nov 7 | 175 x 45088 x 93.3 | ||
| 1997 Nov 7 | 2151 | Lower peri, 50s burn | 135 x 45088 x 93.3 |
| 1997 Nov 14 | 124 x 44383 x 93.3 | ||
| 1997 Nov 15 | Lower peri | 120 x 44383 x 93.3 | |
| 1997 Nov 26 | 123 x 41907 x 93.3 | ||
| 1997 Nov 28 | Dust storm, raise peri | ||
| 1997 Nov 28 | Second peri raise, total 7 km | ||
| 1997 Dec 4 | 0030 | Apo A55 | 123.8 x 39732 x 93.3 |
| 1997 Dec 11 | 1846 | Apo A61 | 131.0 x 39512 x 93.3 |
| 1997 Dec 12 | 127 x 39378 x 93.3 | ||
| 1997 Dec 23 | 122 x 37384 x 93.3 | ||
| 1997 Dec 24 | 2125 | Apo A72 | 129 x 36899 x 93.4 |
| 1997 Dec 27 | 0343 | Apo A74 | 129 x 36518 x 93.4 |
| 1998 Jan 9 | 122 x 32744 x 93.4 | ||
| 1998 Jan 30 | 121 x 27777 x 93.4 | ||
| 1998 Feb 12 | 117 x 25000 x 93.4 | ||
| 1998 Feb 20 | 118 x 23442 x 93.4 | ||
| 1998 Mar 13 | 117 x 20041 x 93.4 | ||
| 1998 Mar 23 | 2310 | Apo 194 ABM raise peri | |
| 1998 Mar 27 | 0857 | Apo 201, ABX-1, 4.4 m/s raise peri 6s burn | 170 x |
| 1998 Mar 27 | 1920 | Apo 202, Turn on science inst. | |
| Science Phasing Orbit | |||
| 1998 Apr 3 | VL1 imaging attempt | ||
| 1998 Jul 17 | 176 x 17881 x 93.4? | ||
| 1998 Aug 19 | 1408 | Phobos pass | |
| 1998 Aug 19 | 1701 | Phobos pass 1080 km | |
| 1998 Aug 28 | 11.6h 174 x 17861 x 93.4? | ||
| 1998 Aug 31 | 1946 | Phobos pass | |
| 1998 Sep 12 | 2241 | Phobos pass 265 km | |
| 1998 Sep 15 | 172 x 17854 x 93.4? | ||
| 1998 Sep 17 | AB-1 cancelled, safemode | ||
| 1998 Sep 23 | Aerobraking Phase 2 | ||
| 1998 Sep 23 | 1749 | AB-1 11.6m/s 15s, Apo 573 | 127 x 17866 x 93 |
| 1998 Sep 24 | 0109 | Peri 573, drag passes begin | |
| 1998 Sep 24 | 0658:40 | AB-2 0.4m/s, Apo 574 | |
| 1998 Sep 25 | 0611:17 | AB-3 0.2m/s, Apo 576 | |
| 1998 Sep 25 | Apo 577 | 120 x 17720 x 93 | |
| 1998 Sep 26 | ABM down, Apo 580 | ||
| 1998 Sep 27 | ABM down, Apo 582 | ||
| 1998 Oct 7 | 115 x 15903 x 93? | ||
| 1998 Oct 12 | ABM immediate up, 0.1m/s, Apo 615 | ||
| 1998 Oct 13 | 116 x 14991 x 93? | ||
| 1998 Oct 15 | ABM down Apo 622 | ||
| 1998 Oct 18 | 114 x 14074 x 93? | ||
| 1998 Oct 19 | ABM up Apo 632 | ||
| 1998 Oct 20 | ABM up Apo 635 | ||
| 1998 Oct 21 | 113 x 13514 x 93 | ||
| 1998 Oct 23 | 1300? | ABM down Apo 641 | |
| 1998 Oct 25 | 0000? | ABM down Apo 647 | |
| 1998 Oct 28 | 113 x 12200 x 93 | ||
| 1998 Nov 1 | ABM up Apo 668 | ||
| 1998 Nov 5 | 112 x 10669 x 93 | ||
| ABM Apo 682 | |||
| ABM Apo 685 | |||
| 1998 Nov 9 | 114 x 10073 x 93 | ||
| 1998 Nov 12 | ABM apo 710 | ||
| 1998 Nov 15 | ABM apo 714 | ||
| 1998 Nov 16 | ABM apo 726 | ||
| 1998 Nov 16 | 113 x 8950 x 93 | ||
| 1998 Nov 19 | 113 x 8536 x 93 | ||
| 1998 Nov 20 | ABM, apo 747 | ||
| 1998 Nov 22 | 114 x 8128 x 93 | ||
| 1998 Nov 25 | ABM, apo 764 | ||
| 1998 Nov 30 | 112 x 7215 x 93 | ||
| ABM, apo 789 | |||
| 1998 Dec 2 | 291.03 112 x 6940 x 93 | ||
| 1998 Dec 4 | ABM, apo 804 | ||
| 1998 Dec 4 | ABM, apo 814 | ||
| 1998 Dec 5 | 112 x 6617 x 93 | ||
| 1998 Dec 9 | 112 x 6203 x 93 | ||
| 1998 Dec 9 | ABM Peri raise, apo 834 | ||
| 1998 Dec 11 | ABM Periapsis raise, apo 845 | ||
| 1998 Dec 12 | 1240 | Flyby Phobos 300 km, orbit 849 | |
| 1998 Dec 14 | 113.8 x 5745 x 93 | ||
| 1999 Dec 16 | ABM up, Apo 873 | ||
| 1999 Jan 2 | 209.2 109 x 4216 x 93 | ||
| ABM up, Apo 979 | |||
| 1999 Jan 6 | 197.4 112 x 3794 x 93 | ||
| ABM up, Apo 1000 | |||
| 1999 Jan 8 | 192.7 110 x 3629 x 93 | ||
| 1999 Jan 11 | 1502 | Apo 1044 | 109 x 3337 x 93.1 |
| 1999 Jan 13 | 1524 | Apo 1060 | 108 x 3086 x 93.1 |
| 1999 Jan 14 | 1159 | Apo 1067 | 107 x 2978 x 93.0 |
| ABM up, Apo 1069 | |||
| 1999 Jan 16 | 1237 | Apo 1084 | 107 x 2741 x 93.0 |
| 1999 Jan 20 | 1354 | Apo 1120 | 105 x 2252 x 93.0 |
| 1999 Jan 23 | 1708 | Apo 1150 | 104 x 1849 x 93.1 |
| 1999 Jan 26 | 1044 | Apo 1178 | 104 x 1459 x 93.1 |
| 1999 Jan 27 | 1114 | Apo 1189 | 104 x 1297 x 93.1 |
| 1999 Jan 28 | 0851 | Apo 1199 | 101 x 1133 x 93.1 |
| 1999 Jan 28 | 1730 | ABM Glide trim, Apo 1203 | |
| 1999 Jan 28 | 1925 | Apo 1204 | 103 x 1050 x 93.1 |
| 1999 Jan 29 | 1634 | ABM Up1 Walk-out burn Apo1214 | 107 x 901 x 93.1 |
| 1999 Jan 30 | 1600 | Apo 1222 OWLT = 9:59 | 106 x 847 x 93 |
| 1999 Jan 31 | 0400 | Apo1228 | 106 x 795 x 93 |
| 1999 Feb 1 | 0400 | ABM Up2 burn Apo 1238 | 109 x 684 x 93.1 |
| 1999 Feb 1 | ABM Up3 burn Apo1256 | 110 x 641 x 93.1 | |
| 1999 Feb 2 | 0848 | Apo 1259 | 113 x 551 x 93.1 |
| 1999 Feb 2 | 2013 | Apo 1265 | 113 x 525 x 93.1 |
| 1999 Feb 2 | ABM Up4 burn Apo1269 | ||
| 1999 Feb 3 | 0542 | Apo 1270 | 116 x 506 x 93.1 |
| 1999 Feb 4 | 0801:31 | ABX-2 Apo1284 exit burn 61.9m/s 72s | 381 x 451 x 93.1 |
| 1999 Feb 19 | 118.50 414 x 419 x 92.95 | ||
| 1999 Feb 19 | TMO (Transfer to Mapping Orbit) 22 m/s, rev 1473, 26s | ||
| 1999 Feb 19 | 117.00 367 x 438 x 92.91 | ||
| 1999 Mar 9 | 0000 | Begin prime mapping mission | |
| 1999 Apr 16 | HGA hinge problem, contingency | ||
| 1999 Apr 29 | Resume mapping | ||
| 1999 May 6 | Begin nominal mapping | ||
| 1999 May 7 | 1443:49 | OTM1 2 min, 3.5m/s | |
| 1999 Jun 10 | 1149:39 | OTM2 fix ground track repeat | |
| 1999 Aug 11s | OTM3 | ||
| 2001 Jan 18 | Reaction wheel failure | ||
| 2001 Jan 31 | Primary Mission complete | ||
| 2001 Jan 31 | Extended Mission begins | ||
| 2001 May | Safemode | ||
| 2001 Sep | Safemode | ||
| 2001 Oct | Safemode | ||
| 2002 Feb 27 | Safemode | ||
| 2002 Mar | Restored | ||
| 2002 Dec 12 | Complete second Mars year | ||
| 2003 Jun 1 | Image Phobos from 9670 km | ||
| 2006 Oct 31 | 117.81 356 x 419 x 93.0 | ||
| 2006 Nov 3 | 0025? | Loss of signal | |
| 0106 | Failed AOS | ||
Payload:
- MOC Mars Orbiter Camera
- TES Thermal emission spectrometer
- MOLA Mars Orbiting Laser altimeter
- USO Ultra Stable Oscillator - Radio science
- MAG/ER Magnetometer/electron reflectometer
- MR Mars relay system
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