Editing Mars 3 (section)

==Orbiter==
The primary purpose of the 4M-V orbiter was to study the topography of the Martian surface; analyze its soil composition; measure various properties of the atmosphere; monitor "solar radiation, the solar wind and the interplanetary and martian magnetic fields".<ref name=nssdc/> In addition, it served as a "communications relay to send signals from the lander to Earth".<ref name=nssdc/>

The orbiter suffered from a partial loss of fuel and did not have enough to put itself into a planned 25-hour orbit. The engine instead performed a truncated burn to put the spacecraft into a highly-elliptical long-period (12 day, 19 hours) orbit about Mars.

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 November 14, 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. 

The Mars 3 orbiter sent back data covering the period from December 1971 to March 1972, although transmissions continued through August. It was announced that Mars 3 had completed their mission by August 22, 1972, after 20 orbits. The probe, combined with Mars 2, sent back a total of 60 pictures. The images and data revealed mountains as high as 22&nbsp;km, atomic hydrogen and oxygen in the upper atmosphere, surface temperatures ranging from −110&nbsp;°C to +13&nbsp;°C, surface pressures of 5.5 to 6 mb, water vapor concentrations 5000 times less than in Earth's atmosphere, the base of the ionosphere starting at 80 to 110&nbsp;km altitude, and grains from dust storms as high as 7&nbsp;km in the atmosphere. The images and data enabled creation of surface relief maps,<ref name=Perminov1/> and gave information on the Martian [[gravity]] and [[magnetic field]]s.