After the occurrence of dust storms on the planet for several months following its arrival, the orbiter managed to send back clear pictures of the surface.

NASA still held out hope that another Mariner probe and Atlas-Centaur could be readied before the 1971 Mars launch window closed.

Convair also had an available Centaur stage on hand and could have an Atlas readied in time, but the idea was ultimately abandoned for lack of funding.

For atittude control, the spacecraft contained 2 sets of 6 nitrogen jets on the tip of the solar panels.

Attitude knowledge was provided by a Sun sensor, a Canopus star tracker, gyroscopes, an inertial reference unit, and an accelerometer.

[6][1] When Mariner 9 arrived at Mars on November 10, 1971, planetary scientists were surprised (although had anticipated during perihelic opposition) to find the atmosphere was thick with "a planet-wide robe of dust, the largest storm ever observed.

On November 14 1971 after slowing down, Mariner 9's computer was thus reprogrammed from Earth to delay imaging of the surface for a couple of months until the dust settled.

However, surface-obscured images did contribute to the collection of Mars science, including understanding of the existence of several huge high-altitude volcanoes of the Tharsis Bulge that gradually became visible as the dust storm abated.

This unexpected situation made a strong case for the desirability of studying a planet from orbit rather than merely flying past.

[1] The images revealed river beds, craters, massive extinct volcanoes (such as Olympus Mons, the largest known volcano in the Solar System; Mariner 9 led directly to its reclassification from Nix Olympica), canyons (including the Valles Marineris, a system of canyons over about 4,020 kilometres (2,500 mi) long), evidence of wind and water erosion and deposition, weather fronts, fogs, and more.

The Infrared Interferometer Spectrometer (IRIS) team was led by Dr. Rudolf A. Hanel from NASA Goddard Spaceflight Center (GSFC).

The Infrared Radiometer (IRR) team was led by Professor Gerald Neugebauer from the California Institute of Technology (Caltech).

The circuitry used was called the "Green Machine", which employed the fast Fourier transform, increasing the decoding speed by a factor of three.