Mariner 9 was an American robotic space probe launched to Mars in May 1971. It was the first spacecraft to image the Martian surface extensively, and for this reason is sometimes referred to as “the photographs from Mars”. Mariner 9 returned more data about Mars than all other planetary missions up to that time combined.
It became operational on November 14, 1971, and ended operations on October 27, 1972. The mission succeeded in returning closeup images of approximately two-thirds of the Martian surface, including Valles Marineris, the largest canyon in the solar system. Images revealed volcanic features such as Olympus Mons—the tallest mountain in the solar system—and vast plains such as Acidalia Planitia. Mariner 9 also proved conclusively that Mars has no global magnetic field like Earth’s. Before its batteries failed after 342 days of operation (1 Martian year), it discovered Phobos and Deimos—two small moons orbiting very close to Mars—and provided evidence that Mars once had dense atmospheres and abundant water at some point in its history.
Launched by an Atlas-Centaur rocket on May 30, 1971 from Cape Canaveral Air Force Station’s Launch Complex 36B, Mariner 9 arrived at Mars on November 13 after a journey of six months and five days. It went into orbit aroundMars exactly one week later on November 20 at an altitude of 3480km; inclination 65°; period 3h 39m (24hr day). With six 84cm diameter parabolic antennas it began returning pictures soon after arrival via UHF relay through three tracking stations: Canberra Deep Space Communication Complex near Canberra Australia (primary); Goldstone Deep Space Communications Complex near Barstow California (secondary); Madrid Deep Space Communications Complex near Madrid Spain (tertiary). The best images were those with resolution down to 1m or better; sufficient for mapping purposes but not good enough for geologic studies which required 75cm or better resolution . Most pictures have resolutions between 4 and 8m; about 1000 were returned with resolutions under 40m All together over 17000 pictures were taken during the mission amounting to some 100GB of raw image data which were telemetered back to earth over a period of nine months using travelling wave tube amplifiers operating at 400Watts peak power output.. Radio science experiments conducted during transmission windows amounted to another 700MB To conserve onboard tape recorder storage limited only to 2GB total capacity both picture taking and playback operations were halted when out of range of ground stations except during eclipse seasons when solar powered rechargeable batteries could be used for short durations.. Two separate teams processed imagery independently with final results being compared for consistency.. Maps compiled from Mariner9 images covered nearly 4 million square kilometers or roughly 60%ofMars’surface including all visible latitudes from 60Nto60S.. Smaller areas at much higher resolution approaching 1mwere mapped in detail particularly along proposed paths for future landers.. Selected targets included potential landing sites within VallesMarineris canyons complex ,volcanoes AscraeusMons ,AlbaPatera ,ErebusCavus ,Elysium Mons ,HadriacumChasma region east Of Tharsis bulge including HecatesTholus ,UlyssesCrater potential source region For north polar cap residual ice deposits,, south polar cap,,&PhobosDeimos satellites After initial checkout & calibration procedures imaging operations commenced Nov14th & continued thru early March1972 when loss offunction due To depletion offuelin reaction control thrusters led Todecision TOMaintain station keeping attitude using gyroscopes rather than expend remaining fuel reserves ..With cameras pointing toward sunlit hemisphere imaging resumed July 1972 continuing until termination offeedback commands from earth Oct 27th1972 when batteries finally failed due Tovoltage sag below minimum operating levels . In addition Toboth optical CCD array & film cameras infrared radiometers measured atmospheric composition,, temperature profiles And sublimation rates Ofpolar caps while ultraviolet spectrometers probing upper atmosphere searched Formolecular oxygen believed necessaryfor life processes,,charted variability OffamousMartian dust storms& studied interaction Betweenthe planet’s ionosphere& solar wind particles flowing past it ..Magnetic tapes containing recorded digital data representing 17000 plus images & 700 MB Of radio science experiment information remain securely stored today atthe Jet Propulsion Laboratory Pasadena Ca awaiting possible future analysis & interpretation