6.3 Unit Conversion 139
I. Launch
- Delta II 7425
- Launched January 3, 1999
- Launch mass: 574 kilograms
II. Cruise
- Thruster attitude control
- Four trajectory-correction
maneuvers (TCM); site-
adjustment maneuver
September 1, 1999;
contingency 5th TCM at
entry –24 hours - Eleven month cruise
- Near-simultaneous tracking
with Mars Climate Orbiter
or Mars Global Surveyor
during approach
III. Entry, Descent, Landing
- Arrival: December 3, 1999
- Jettison cruise stage;
microprobes separate from
cruise stage - Hypersonic entry
- Parachute descent;
propulsive landing - Descent imaging of
landing site
IV. Landed Operations
- Lands in Martian spring at
76 degrees South latitude,
195 degrees West
longitude (76S, 195W) - 90-day landed mission
- Meteorology, imaging,
soil analysis, trenching - Data relay via Mars
Climate Orbiter, Mars
Global Surveyor, or direct-
to-Earth high-gain antenna
I.
II.
III.
IV.
■Figure 6.1 Mars polar lander mission overview.
Source:Courtesy of NASA.error in a transfer of information between theMars Climate Orbiterspacecraft team in
Colorado and the mission navigation team in California led to the loss of the spacecraft.”
The peer review findings indicated that one team used U.S. Customary units (e.g., foot and
pound) while the other used SI units (e.g., meter and kilogram) for a key spacecraft oper-
ation. According to NASA, the information exchanged between the teams was critical to
the maneuvers required to place the spacecraft in the proper Mars orbit. An overview of the
Mars polar lander mission is given in Figure 6.1.Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀