SPACECRAFT ACCIDENTS: EXAMINING THE PAST, IMPROVING THE FUTURE Mars Observer (MO)

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SPACECRAFT ACCIDENTS EXAMINING THE PAST,
IMPROVING THE FUTUREMars Observer (MO)

• Bryan Palaszewski
• working with the
• Digital Learning Network
• NASA Glenn Research Center

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Mars Observer (1/3)

• Launched from Earth on September 25, 1992
• Payload on spacecraft
• Gamma Ray Spectrometer (GRS)
• Magnetometer and Electron Reflectometer (MAG/ER)
• Mars Observer Laser Altimeter (MOLA)
• Pressure Modulator Infrared

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Mars Observer (2/3)

• Payload on spacecraft (continued)
• Radiometer (PMIRR)
• Thermal Emission Spectrometer (TES)
• Mars Observer Camera (MOC)
• The Mars Observer spacecraft was to be the first
  U.S. spacecraft to study Mars since the Viking
  missions 18 years before.

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Mars Observer (3/3)

• The Mars Observer spacecraft fell silent just 3
  days prior to entering orbit around Mars
  following the pressurization of the rocket engine
  fuel tanks. The rocket engine was to slow the
  spacecraft into Mars orbit.
• Lost August 21, 1993
• Planned to enter Mars orbit on August 24, 1993

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Lessons Learned Information System (NASA)

• Mars Observer Spacecraft was lost while
  performing the Mars Orbit Insertion maneuver.
• Premature propellant mixing may have caused an
  explosion.
• Spacecraft was qualified for Earth orbit, not the
  Mars environment.
• Qualification testing may not have been proper or
  relevant.

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Mars Observer Accident Causes (1/2)

• The possibility of a propulsion subsystem breach
  actually includes three different possible
  scenarios
• Liquid oxidizer (nitrogen tetroxide) may have
  migrated past a check valve in the pressurization
  lines during the tank pressurization, the
  oxidizer could have been forced into lines
  containing the fuel, liquid monomethylhydrazine,
  causing the line to burst.

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Mars Observer Accident Causes (2/2)

• The possibility of a propulsion subsystem breach
  (continued)
• The pressure regulator could have failed, causing
  the oxidizer tank to over pressurize and burst.
• A small pyrotechnic device, or squib, which was
  fired to open a valve in one of the
  pressurization system's lines, could have been
  ejected from the pyrotechnic valve like a bullet
  and damaged the fuel tank.

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