Editing Mars 2 (section)

==Orbiter==
The Orbiter type was the 4MV, used also for Mars-3 and later Mars and Venera Probes. The orbiter engine performed a burn to put the spacecraft into a {{nowrap|{{convert|1380|x|24,94| km|adj=on}}}}, 18-hour orbit about Mars with an inclination of 48.9 degrees. Scientific instruments were generally turned on for about 30 minutes near periapsis.

The orbiter's primary scientific objectives were to image the Martian surface and clouds, determine the temperature on Mars, study the topography, composition and physical properties of the surface, measure properties of the atmosphere, monitor the [[solar wind]] and the interplanetary and Martian [[magnetic field]]s, and act as a communications relay to send signals from the landers to the Earth.

By coincidence, a particularly large [[Storm#Extraterrestrial storms|dust storm]] on Mars adversely affected the mission.  When [[Mariner 9]] arrived and successfully orbited Mars on 14 November 1971, just two weeks prior to Mars 2 and Mars 3, [[Planetary science|planetary scientists]] were surprised to find the [[celestial body's atmosphere|atmosphere]] was thick with "a planet-wide robe of [[dust]], the largest storm ever observed."  The surface was totally obscured.  Unable to reprogram the mission computers, both Mars 2 and Mars 3 dispatched their landers immediately, and the orbiters used up a significant portion of their available data resources in snapping images of the featureless dust clouds below, rather than the surface mapping intended.<ref name=Pyle2012-M9>
{{cite book |last=Pyle|first=Rod |title=Destination Mars |year=2012 |publisher=[[Prometheus Books]] |isbn=978-1-61614-589-7 |pages=73–78 |quote=...Mars 2 and Mars 3.  Both reached Mars shortly after Mariner 9.  Unfortunately, these Soviet ships were not reprogrammable, as was the case with Mariner 9, and rather than wait out the huge, planet-wide dust storm, they proceeded to follow their programming right on schedule.  Landers were dispatched from each, the first crashing and the second apparently reaching the surface intact but losing radio contact immediately.  The orbiters fared little better; following their simple logic, both used up their available resources snapping images of the featureless dust clouds below.}}</ref>

The Mars 2 orbiter sent back data covering the period from December 1971 to March 1972, although transmissions continued through August. It was announced that Mars 2 and Mars 3 had completed their missions by 22 August 1972, after 362 orbits. The probe, combined with Mars 3, sent back a total of 60 pictures. The images and data revealed mountains as high as {{convert|22|km}}, atomic hydrogen and oxygen in the upper atmosphere, surface temperatures ranging from {{convert|−110|to|13|C}}, surface pressures of 5.5 to 6 mbar (0.55 to 0.6 [[kilopascal|kPa]]), water vapor concentrations 5,000 times less than in the Earth's atmosphere, the base of the ionosphere starting at {{convert|80|to|110|km}} altitude, and grains from dust storms as high as {{convert|7|km}} in the atmosphere. The images and data enabled the creation of surface [[Raised-relief map|relief map]]s,<ref name=Perminov1>{{cite book|last=Perminov|first=V.G.|title=The Difficult Road to Mars - A Brief History of Mars Exploration in the Soviet Union|date=July 1999|publisher=NASA Headquarters History Division|isbn=0-16-058859-6|pages=[https://archive.org/details/difficultroadtom00perm/page/34 34–60]|url=https://archive.org/details/difficultroadtom00perm/page/34}}</ref> and gave information on Martian [[gravity]] and magnetic fields. The orbiter remains in Martian orbit.