On August 21, 1993, during the interplanetary cruise phase, communication with the spacecraft was lost, three days prior to the probe's orbital insertion.

The RCA AS-4000 Ku-band satellite design was used extensively for the spacecraft bus, propulsion, thermal protection, and solar array.

[13] Records the spectrum of gamma rays and neutrons emitted by the radioactive decay of elements contained in the Martian surface.

[15] Collects data on the gravity field and the Martian atmospheric structure with a special emphasis on temporal changes near the polar regions.

The suspected cause of the contamination were measures taken to protect the spacecraft prior to the landfall of Hurricane Andrew which struck the coast of Florida on August 24.

The likely reason for the spacecraft failure was the leakage of fuel and oxidizer vapors through the improperly designed PTFE check valve to the common pressurization system.

Although none of the primary objectives were achieved, the mission provided interplanetary cruise phase data, collected up to the date of last contact.

[20] On August 24, 1993, Mars Observer would turn 180 degrees and ignite the bipropellant thrusters to slow the spacecraft, entering into a highly elliptical orbit.

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.

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.

[23] The engine was derived from one belonging to an Earth orbital satellite and was not designed to lie dormant for months before being fired.

This high spin rate would cause the spacecraft to enter into the "contingency mode," which interrupted the stored command sequence and thus, did not turn the transmitter on.

Additionally, this high spin rate precluded proper orientation of the solar arrays, resulting in discharge of the batteries.