1. SPACECRAFT ACCIDENTS: EXAMINING THE PAST, IMPROVING THE FUTURE Mars Observer (MO) Bryan Palaszewski working with the Digital Learning Network NASA Glenn Research Center

2. 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

3. 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.

4. 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

7. 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.

8. 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.

9. 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.