MARINER 9

On November 14, 1971, Mariner 9 became the first spacecraft to orbit another planet. Six experiments were carried as part of the science payload: television, ultraviolet spectrometer, infrared spectroscopy, infrared radiometry, S-band occultation and celestial mechanics. Two experiments (S-band occultation and celestial mechanics) utilized the radio telemetry subsystem to derive data; the other required specially developed instruments, mounted, and boresighted to each other, on the spacecraft's scan platform. Pre-launch mission planning encompassed two separate, but complementary, missions. The orbit of each spacecraft was optimized to match the corresponding objective. The mapping mission was designed with an Earth-synchronous orbit (about a 12-hr periods) to maximize antenna utilization, or communications efficiency. For maximum surveillance of an area, it was designed with a steep inclination (80 degrees) to the equatorial plane of Mars. The dynamic objective dictated a Mars-synchronous (or sub-synchronous) orbit and a lower (50 degree) inclination for closer observations of specific areas. The plans for the two missions were in detailed stages of development on May 9, 1971 when Mariner 8 was lost because of guidance difficulties in the second stage of the launch vehicle. It was determined that an orbit for a single-spacecraft mission could be developed to meet all basic mission and specific science objectives. A single-spacecraft plan, involving an inclination of 65 degrees, a period of about 12 hours, a periapsis altitude of 1350 Km, and an arrival date of November 14, 1971, was evaluated and formalized in 2 weeks.

Mariner Mars 1971 Project Final Report, Science Experiment Reports, JPL
                   Technical Report 32-1550, Vol. V, Aug. 20, 1973.

extracted metadata from PDS3 catalog and
                    modified to comply with PDS4 Information Model

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