Editing Mariner 9 (section)

== Objectives ==
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[[File:Atlas I-CENTAUR.jpg|thumb|right|Mariner 9 launch]]

Mariner 9 was designed to continue the atmospheric studies begun by [[Mariner 6 and 7]], and to map over 70% of the Martian surface<ref>{{Cite web |title=Mariner 9 - NASA Science |url=https://science.nasa.gov/mission/mariner-9/ |access-date=2024-08-30 |website=science.nasa.gov |date=20 December 2017 |language=en-US}}</ref> from the lowest altitude ({{Convert|1500|km|sp=us}}) and at the highest resolutions (from 1&nbsp;kilometer to 100&nbsp;meters (1,100 to 110&nbsp;yards) per pixel) of any Mars mission up to that point.{{According to whom|date=August 2024}} An infrared [[radiometer]] was included to detect heat sources in search of evidence of [[volcanic activity]]. It was to study temporal changes in the Martian atmosphere and surface. [[Moons of Mars|Mars' two moons]], [[Deimos (moon)|Deimos]] and [[Phobos (moon)|Phobos]], were also to be analyzed. Mariner 9 more than met its objectives.

Under original plans, a dual mission was to be flown like Mariners 6–7, however the launch failure of [[Mariner 8]]<ref name=nasa3/> ruined this scheme and forced NASA planners to fall back on a simpler one-probe mission. NASA still held out hope that another Mariner probe and [[Atlas-Centaur]] could be readied before the 1971 Mars [[launch window]] closed. A few logistical problems emerged, including the lack of an available Centaur payload shroud of the correct configuration for the Mariner probes, however there was a shroud in NASA's inventory which could be modified. [[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.

Mariner 9 was mated to Atlas-Centaur AC-23 on May 9 with investigation into Mariner 8's failure ongoing. The malfunction was traced to a problem in the Centaur's pitch control servoamplifier and because it was not clear if the spacecraft itself had been responsible, [[Electromagnetic interference|RFI]] testing was conducted on Mariner 9 to ensure the probe was not releasing interference that could cause problems with the Centaur's electronics. All testing came back negative and on May 22, a tested and verified rate gyro package arrived from Convair and was installed in the Centaur.

Liftoff took place on May 30 at 22:23:04 UT.<ref name=nasa1/> All launch vehicle systems performed normally and the Mariner separated from the Centaur at 13 minutes and 18 seconds after launch.