Mars Observer—Jack Fisher

Mars Observer as originally planned was to be a low cost Mars orbiter and a successor to Viking. Preliminary mission goals expected the mission to provide planetary magnetic field data, detection of certain spectral line signatures of minerals on the surface, images of the surface at 1 meter/pixel and global elevation data. The February 1984 NASA budget included funding and the release of the JPL RFP was scheduled to for June. The spacecraft was to be launched with the Space Shuttle in 1990. There, however was a significant disagreement between NASA headquarters and JPL. JPL wanted the boost from earth orbital velocity to Mars transfer velocity to be integral with the spacecraft while NASA headquarters wanted a separate stage that could be used with other missions. The final compromise was an RFP that included three potential options: 1. spacecraft only; 2) separate transfer orbit stage and 3) spacecraft with integral propulsion. JPL would be responsible for 1 and 3 while NASA Marshall Space Flight Center would handle Option 2. Working out this compromise delayed the RFP to June 1985.

Hughes saw this as an opportunity to get back into the NASA world of planetary exploration based upon experience building and flying communication satellites with integral propulsion. A proposal team was formed headed by Leo Nolte and Jack Fisher. The Hughes proposal was based upon a modification of Intelsat VI with a despun science platform with and without integral propulsion for Options 1 and 3.

The Mars Observer proposals were submitted in August 1985. Hughes, RCA and Ford Aerospace bid on Options 1 and 3 while Orbital Sciences was the only bidder for Option 2. The proposals were evaluated and best and final offers were submitted in December. After JPL evaluation of the proposals an amendment to the RFP was issued in February 1986 limiting source selection to Options 1 and 2 eliminating work package 3. Shortly thereafter Hughes submitted a protest that was denied.

On March 24, JPL announced that RCA submitted the successful spacecraft proposal for Option No. 1. The spacecraft design was based upon the RCA Satcom, TIROS and DMSP satellites. Note: within a year RCA was purchased by General Electric Astrospace who completed design and construction of the Mars Observer. OSC was the successful bidder for option 2.

          Mars Observer was originally planned to be launched in 1990 by the Space Shuttle. In March 1987, the mission was rescheduled for launch in 1992 with a Titan III due to the loss of Challenger and spacecraft weight increases. Along with the launch delay, budget overruns necessitated the elimination of two instruments to meet the 1992 planned launch.

         Mars Observer was launched on September 25, 1992 aboard a Titan III launch vehicle and a Transfer Orbit Stage that placed the spacecraft into an 11-month, Mars transfer trajectory. Mars Observer was scheduled to perform an orbit insertion maneuver on August 24, 1993. However, contact with the spacecraft was lost on August 21, 1993. Likely reason for spacecraft failure was the leakage of fuel and oxidizer vapors through the improperly designed check valve to the common pressurization system. During interplanetary cruise, the vapor mix had accumulated in feed lines and pressurant lines, resulting in explosion and their rupture after the engine was restarted for routine course correction. The total cost for the mission was estimated to be $813M.

Comment by Steve Dorfman

The Mars Observer was NASA at it’s worst. They believed the TOS stage would a fitting complement to the Shuttle launching communication satellites. Orbital Science was created based on that premise and a successful IPO was launched promising a series of communication satellite launches on shuttle. Unfortunately all the communication satellites contemplated at that time (RCA and Hughes) intended to use integral propulsion, a much more efficient way to transition from the Shuttle to transfer orbit. By eliminating that possibility for Mars NASA clung to the TOS solution for Shuttle transfer orbit to preserve the concept.

The TOS launch of the Mars Observer was the only TOS launched. It was never used for commercial satellites as originally advertised. To its credit Orbital Science did a “pivot” from this flawed strategy and has become a successful Space company building satellites and launch vehicles. But it started from a false premise supported by a misguided NASA.

It is ironic that the mission was also a failure in adapting commercial satellite technology for planetary exploration though Pioneer Venus proved it could be done if done carefully.


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About Jack Fisher

Jack was a systems engineer at Hughes from 1961 to 1992. He contributed to various programs including Surveyor, Pioneer Venus, Galileo, Intelsat VI and innumerable proposals. He was the manager of of the Spacecraft Systems Engineering Lab until his retirement. Upon retirement Jack taught systems engineering at a number of national and international venues.