This Day in Tech History

On This Day . . .

Lost in Space

Mars_Observer August 21, 1993:  Mars Observer Lost

into orbit around Mars. The reason for the loss of contact was never definitively determined, but the most probable cause was a rupture of a fuel tank.

The Mars Observer spacecraft was launched by NASA on September 25, 1992 to study the Martian surface, atmosphere, climate and magnetic field.

Titan III vehicle launching the Mars Observer spacecraft.

Titan III vehicle launching the Mars Observer spacecraft.

The MOC spacecraft bus measured 1.1-meters tall, 2.2-meters wide, and 1.6-meters deep (1 meter = 3.28084 feet). The spacecraft was based on previous satellite designs, originally intended and developed to orbit Earth. Power was supplied to the spacecraft through a six panel solar array, measuring 7.0-meters wide and 3.7-meters tall, and would provide an average of 1147-Watts when in orbit.

Mars Observer Camera (MOC)

Mars Observer Camera (MOC)

Mars Observer Laser Altimeter (MOLA)

Mars Observer Laser Altimeter (MOLA)

Thermal Emission Spectrometer (TES)

Thermal Emission Spectrometer (TES)

Magnetometer and Electron Reflectometer (MAG/ER)

Magnetometer and Electron Reflectometer (MAG/ER)

The computing system on the spacecraft was a semiautonomous system able to store up to 2000 commands in the included 64 kilobytes of RAM. To record data, redundant digital tape recorders (DTR) were included and each capable of storing up to 187.5-megabytes, for later playback to the Deep Space Network.

722px-Mars_Observer_-_spacecraft_diagram_-rev2

On August 21, 1993, three days prior to the scheduled Mars orbital insertion, there was an “inexplicable” loss of contact with Mars Observer. New commands were sent every 20 minutes in the hopes that the spacecraft had drifted off course and could regain contact. However, the attempt was unsuccessful. It is unknown whether the spacecraft was able to follow its automatic programming and go into Mars orbit or if it flew by Mars and is now in a heliocentric orbit (a heliocentric orbit is an orbit around the Sun).

On January 4, 1994, an independent investigation board from the Naval Research Laboratory, announced their findings: the most probable cause in the loss of communication was a rupture of the fuel pressurization tank in the spacecraft’s propulsion system.

It is believed that hypergolic fuel may have leaked past valves in the system during the cruise to Mars, allowing the fuel and oxidizer to combine prematurely before reaching the combustion chamber. The leaking fuel and gas probably resulted in a high spin rate, causing the spacecraft to enter into the “contingency mode”; this interrupted the stored command sequence and did not turn the transmitter on. The engine was derived from one belonging to an Earth orbital satellite and was not designed to lie dormant for months before being fired.

Mars Observer in the Payload Hazardous Servicing Facility.

Mars Observer in the Payload Hazardous Servicing Facility.

Technician assembling the Mars Observer space probe.

Technician assembling the Mars Observer space probe.

 

The Mars Exploration Program was formed officially in the wake of the Mars Observer’s failure in September 1993. The goals of that program include identifying the location of water, and preparing for Humans on Mars. It also supported a Mars sample return.

Dick Tufeld Tribute – Lost in Space Robot

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