The Mars Climate Orbiter failed due to a mismatch between the units used by Lockheed Martin to calculate thruster firings and the units expected by NASA for navigation. Lockheed Martin used English units (pounds, feet, inches) while NASA expected metric units. As a result, trajectory correction maneuvers put the orbiter in a lower orbit than intended, and it burned up in the Martian atmosphere upon arrival. An investigation found the root cause was a failure in NASA's engineering systems and processes to detect the mismatch in units between the teams.

1. Failure of Mars Climate
Orbiter

3.  Mars climate orbiter is also called Mars Surveyor ‘98
Orbiter.
 Manufactured by Lockheed Martin which is industrial
partner of NASA.
 It was launched by NASA by Delta II 7425 rocket from
Cape Canaveral.
 Launched on December 11, 1998.
 Weight: 338 Kilograms
 Cost of mission $193.25 million.

5.  To determine existence of water on Mars.
 Monitor weather and atmospheric conditions on Mars.
 Determining temperature and surface changes on
Mars.
 Monitor water vapour and dust contents in
atmosphere.

6.  It contained 8 thrusters. 4 (27 Newton) for controlling
altitude and other 4 (0.9 N) for trajectory correction.
 Scientific instruments:
1. Mars Colour Imager (for taking images)
2. Pressure Modulator Infrared Radiometer (for
studying atmosphere)
3. Star Tracker (for determining position).
 Trajectory Correction: means to change path or orbit
of spacecraft to get into desired path or orbit. For these
Thrusters are fired.

8.  Four trajectory
corrections done before
spacecraft reached Mars.
 TCM : Trajectory
Correction Maneuver

9.  When spacecraft reached
Mars it was 49 seconds early
than expected.
 Orbit altitude was 60km
than the intended orbit
altitude of 150Km.
Encounterwith Mars

10.  Nov. 10,1999, Mars Climate Orbiter Mishap
Investigation Board released a report of failure.
 According to report on Sept 15 trajectory correction
was done to bring orbiter at 226Km altitude.
 But it was found that orbiter was in much lower orbit
than 150Km. 80Km was minimum altitude that the
orbiter could survive.
 On Sept 23,
1. 9am: Main engine was started and fired for 16
minutes for entering orbit of Mars.
2. After few minutes it lost contact with ground.
3. On Sept 25 mission was declared a loss.

11.  Team of engineers of Lockheed developed a software
whose results were in English units (Pound, foot,
inch).
 Mission navigation team of NASA used these results
for its system ,expecting it to be in SI units.
 During mission, the software of thrusters calculated
force in English units.
 Results of that software were used in trajectory
corrections expecting it to be in SI.

12.  1 Pound force = 4.45
Newton force
 The main failure was of
NASA’s engineering
systems and balance and
check process to detect the
error.

13.  Spacecraft went in lower
altitude (57 Km) than
expected (226 Km).
 Spacecraft burned due
to atmospheric friction
and broke into pieces.
 Last contact with
spacecraft was on
September 30, 1999.
NASA lost Mars Climate
Orbiter on this day.