General Electric (U.S.). Astro Space Division.

The Mars Observer (MO) was the first of the Planetary Observer missions, a series of low cost, modest scope missions for exploration of the inner solar system. This set had been recommended by the Solar System Exploration Committee of the NASA Advisory Council as a key element in the core program of solar system exploration through the year 2000. The Mars Observer was a strong start to the Planetary Observer program and to demonstrate the adaptability of existing spacecraft design to subsequent missions in this program. It was also fully relevant to the goals of solar system exploration, identified by the Space Sciences Board of the National Academy of Science.

The FY85 NASA Budget established the planning estimate for the development costs (through launch plus 30 days) for Mars Observer at $212M in FY85 dollars excluding the upper stage or injection capability, Space Transportation System integration and STS launch costs, and the Jet Propulsion Laboratory institutional costs of Tracking and Data Acquisition and of the Space Flight Operations Center. The Mission Operations and Data Analysis phase of the project was estimated at $24M in FY85 dollars.

MO was NASA's first single spacecraft planetary explorer launched with a firm, fixed-priced contract. The contract which included a set of spare spacecraft components and mission support operations, provided for profit to be based on the amount of scientific data returned over the useful scientific life of the three-year mission. That meant General Electric got no profit for the year while the spacecraft was en route to Mars. Profit payments begin only after the first 5 % of scientific data was received and did not include the final 5% of data.

Mars Observer was programmed to be the first mission returning to Mars since the 1976 Viking mission. Spacecraft development costs were controlled by basing its design on civilian and military Earth-orbiting spacecraft designs. General Electric's Astro-Space Division produced the Mars Observer spacecraft carrier vehicle, or bus. The Titan III launch vehicle was provided by Martin Marietta Commercial Titan, Inc.; the Transfer Orbit Stage (TOS) was supplied by the Orbital Sciences Corporation and built by the Martin Marietta Astronautics.

The Jet Propulsion Laboratory had been assigned management of the project for the Office of Space Science and Application. JPL's responsibilities for acquiring the spacecraft included scientific instruments, conducting of mission operations, and also operating the center for Tracking and Data Acquisition System, and the Space Flight Operations Center. Further, JPL approved the preliminary design review for all eight of the spacecraft's instruments. In addition, the ultra-stable oscillator that JPL was supplying for radio-science investigations passed critical design review which was undergoing fabrication at the Applied Physics Laboratory of Johns Hopkins University.

Also passing the CDR stage were the magnetometer and electron reflectometer built by NASA's Goddard Space Fight Center and the thermal-emission spectrometer built by the Santa Barbara Research Center.

Mars Observer was launched on September 25, 1992, aboard a Titan III launch vehicle from Cape Canaveral Air Force Station in Florida. The objective of the Mars Observer mission was to place a spacecraft in parking orbit around Earth by the Titan III launch vehicle and injected onto the trans-Mars heliocentric trajectory by the TOS upper-stage vehicle about Mars for one Martian year (687days) providing a nadir-oriented platform from which to carry out a series of cost-effective experiments and measurements designed to meet the scientific objectives of the mission. The spacecraft was to be inserted into an intermediate phasing orbit. This orbit was adjusted to a circular Sun-synchronous mapping orbit at approximately 360-km altitude and 93° inclination toward the planet's equator.

At the end of the scheduled mapping mission (December 1993 through October 1995), the spacecraft was to serve as a data relay station to supplement the data return from two Mars balloon packages to be deployed from a Russian Mars '94 spacecraft. The orbit then was to be raised in altitude to preclude impact with the planet, in compliance with planetary protection policy.

The science investigations utilized instruments and experiments selected to cover the measurement objectives for mineralogical, elemental, and condensation abundance; temperature, ozone, water, and dust profiles; and topography and magnetic field. A radio science experiment had been selected to determine the figure, gravitational field, and atmospheric refractivity profiles of Mars. These objectives were to be obtained by measurement of the spacecraft orbital position (Earth range) and velocity change (Doppler shift of the X-band telemetry carrier signal).

Phase changes and attenuation of this signal during spacecraft occultation immersion/emersion also indicated the Mars atmospheric density profile. Instrument data was recorded continously during the mission. Data return was planned via 34-meter Deep Space Network stations on a third day, dependent upon availability of a 70-meter antenna and telecommunications link capability.

Mars Observer had completed an 11-month, 711-million-kilometer (442-million-mile) journey to Mars and was within three days of entering orbit around the planet when it fell silent at about 1:00 Universal Time on August 22, 1993. (6 p.m. Pacific Daylight Time on August 21st). No environmental impact issues had been nor were expected to be identified.

The spacecraft was about to begin pressurizing its fuel tanks preparation for the August 24st orbit-inserting maneuver when its transmitters were turned off and the spacecaft was never heard from again. It was the first loss of a United States planetary mission in 22 years.

In conclusion of Mars Observer operations, JPL attempted the last realisitc chance to validate that the spacecaft still existed and was properly operating-except for its telemetry transmitter. That occured in late September, during a search for a beacon from a radio relay system onboard the spacecraft by radio astronomy antennas at Jodrell Bank in England, at Standford University, and at the Goldstone tracking facility near Barstow.

A study team, chaired by Dr. Charles Elachi, Assistant Laboratory Director at the time, for the Office of Space Science and Instruments, did evaluate all of the possible options, including those that did involve international cooperation, and heard proposals from the United States industry in November. Formal recommendations were expected to be presented to NASA Headquarters on November 18, 1993.

A NASA review board spent several months investigating the loss and concluded that the most plausible theory was that a critical failure in the propulsion system disabled Mars Observer several days before arriving at Mars. The board recommended changes to the design to prevent such an occurrence from happening on Mars Global Surveyor, Mars Climate Orbiter (1998) and the Mars Surveyor 2001 Orbiter.

While minimal support for ground-tracking of Mars Observer did continue through mid February, JPL had begun a Mars Recovery Study Team effort to explore the most cost-effective, low-risk ways of recovering the Mars Observer science during the next Mars launch opportunities in 1996, 1998, and 2000.

From the description of Mars Observer Preliminary Design Reviews and Critical Design Reviews Collection, 1986-1992. (Jet Propulsion Laboratory Library and Archives). WorldCat record id: 733102149