1999-001A
The MS 1998 Lander (Mars Polar Lander) is built by Lockheed Martin Astronautics and was launched on 1999 Jan 3 by Delta 7425. It was to land near the south pole at 195W 76S.
in Dec 1999. (the ice-free safe zone is 170 to 230W, 75 to 76S). It is 1.0m wide and 0.5m high. The aeroshell is based on the MPF aeroshell, but the lander uses a Viking-type rocket descent system. Attached to the aeroshell is a cruise stage with solar panels. The lander uses solar arrays for power, and will terminate operations as the winter begins. The Lander has four 22N REM engines used during cruise, using the same 64 kg hydrazine propellant tanks as the descent engines.
Aeroshell ejection is followed by propulsive terminal descent. The MARDI imager, mounted on the lander underside, operates during descent. The SSI imager, used on the surface, is similar to the MPF lander's.
Landing near the south pole is during local spring. MPL will dig a trench and collect soil samples for analysis. It will search for near surface ice and look for evidence of climatic changes: however,nothing was heard from the lander after scheduled Cruise Stage separation. A review board suggested the most likely cause was a design flaw in a touchdown sensor causing the engines to shut of at 40m altitude and impact at 55 kph; however, when the successor Phoenix mission was being ground-tested, it was discovered that the Cruise separation itself probably did not occur. A design error exposed critical parts of the separation system to excessively low temperatures which would have stopped them working. The aeroshell entered the atmosphere with the cruise stage still attached, and the spacecraft was probably destroyed and burnt up during entry.
Estimated impact location was 76.1S 195.3W.
Planned B-plane miss at injection (+60000,-20000) km. Mass injected: 583 kg, with PAM-D 2141 kg full 132 kg empty. 1997 planned injection data: 11.165 km2/s2, RLA DLA =235.35, 0.92. Arival data at 125 km: 143.37 -62.57 az 173.69, fpa -13.25, V 6.91, for landing at 210,-76.
| MPL | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1999 Jan 3 | 2021:10 | Launch Delta 7425 | CC LC17B |
| T+4:24 MECO | |||
| T+4:32 Stage 1 sep | |||
| T+4:37 Stage 2 burn | |||
| T+4:42 Fairing sep | |||
| 2032:32 | T+11:22 SECO-1 | 157 x 246 x 28.4 | |
| 2055:21 | T+34:11 Stage 2 restart | ||
| 2055:40 | T+34:30 SECO-2 | 237 x 770 x 28.4 | |
| 2056:33 | T+35:23 Stage 2 sep | ||
| 2057:10 | T+36:00 Stage 3 burn | ||
| 2058:38 | T+37:28 TECO 293 km 11.434 km/s | 0.97 x 1.45 AU | |
| T+42:10 Yo-yo deploy | |||
| 2103:25 | T+42:15 Stage 3 sep | 185 x -84447 x 28.43 | |
| Deploy solar panels | |||
| 1999 Jan 4 | 0543 | Pass EL1:4 | |
| 1999 Jan 8 | 1548? | Exit Earth sphere 1.5Mkm | |
| 1999 Jan 21 | 1227 | TCM-1, 3min 16m/s | |
| 1999 Mar 16 | 1305 | TCM-2, 10s, 0.9m/s | |
| 1999 Sep 1 | 1700s | TCM-3, site adjust 2.3m/s | |
| 1999 Oct 30 | 1728 | TCM-4 site adjust 12s | |
| 1999 Nov 30 | 1800 | TCM-5 0.1m/s 3.5 Mkm from Mars | |
| 1999 Dec 1 | 0615 | Enter Mars sphere | |
| 1999 Dec 2 | 0000? | PAM-D enter Mars sphere | |
| 1999 Dec 3 | 1339 | TCM-6, 8s | |
| 1999 Dec 3 | Mars arrival OWLT = 14m | ||
| 1949 | Transmitter off | ||
| E-7h TCM-5 at 125000 km | |||
| 1951:00 | E-5min L-10 min Cruise stage sep | ||
| 1951:18 | DS2 sep | ||
| 1955 | DS2 entry | ||
| 1956 | E-0 L-5 Entry 6.91 km/s, 125 km, -13.1 deg | ||
| E+0:33 Hypersonic ops begin | |||
| 1958 | E+2:30 Parachute deploy 7.3 km | ||
| E+2:37 MARDI imaging begins | |||
| E+2:37 Aeroshell sep | |||
| E+2:39 Landing legs deployed | |||
| E+2:40 Landing radar on | |||
| E+4:00 Radar lock, 2.5 km | |||
| 2000 | E+4:00 Backshell sep 1.8 km | ||
| E+4:01 Landing engines on | |||
| 1999 Dec 3 | 1959 | DS2 impact | |
| 2001 | Landing | ||
| 2000 | PAM-D pass at 63000 km | ||
| 1999 Dec 5 | 1600? | PAM-D leave Mars sphere | |
| 2000 Feb 29 | End primary mission | ||
Payload:
- MARDI Mars Descent Imager
- LIDAR Lidar (light detection and ranging) for dust and aerosols, IKI/RKA
- MVACS Mars Volatile and Climate Surveyor
- SSI Stereo surface imager
- RA Robotic arm (2m)
- RAC Robotic arm camera
- TEGA Thermal and evolved gas analyzer
- MET Meteorological package
