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The Mars 2 through Mars 7 spacecraft were of a new, heavy design, weighing approximately 5 tons and requiring the Proton booster for launch. They were designed to deliver an orbiter and a lander to Mars. The orbiter design was similar to the later heavy Venera probes to Venus (Veneras 9 through the Vega probes to Venus and Halley's comet in 1985). The orbiter bus design was likely somewhat rushed into service and immature, considering that it performed very reliably in the Venera variant after 1975Events January January 1 Watergate scandal: John N. Mitchell, H. Haldeman, John D. Ehrlichman are found guilty of the Watergate cover-up and are sentenced to 30 months to 8 years in jail on February 21 January 5 The Tasman Bridge in Tasmania, Australia, i. This reliability problem was common to much Soviet space hardware from the late 1960s and early 1970s and was largely corrected with a deliberate policy of consolidating (or "debugging") existing designs rather than introducing new ones which was implemented in the mid-1970s.
The Mars 2 and Mars 3 missions consisted of identical spacecraft, each with an orbiter and an attached lander; they were the first human artifacts to touch down on Mars. The orbiters' 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 windA solar wind is a stream of particles (mostly high-energy protons ~ 500 keV) which are ejected from the upper atmosphere of a star. In the solar system, the composition of this plasma is identical to the Sun's corona, 73% hydrogen and 25% helium with the and the interplanetary and Martian magnetic fieldIn physics, a magnetic field is an entity produced by moving electric charges ( electric currents) that exerts a force on other moving charges. The quantum-mechanical spin of a particle produces magnetic fields and is acted on by them as though it were as, and act as communications relays to send signals from the landers to Earth. Mars 2 and 3 were launched by Tyazheliy Sputniks.
Mars 2 released the descent module 4.5 hours before reaching Mars on November 27November 27 is the 331st day (332nd on leap years) of the year. There are 34 days remaining. Events 399 St. Anastius I becomes Pope. 1095 Pope Urban II declares the First Crusade at the Council of Clermont. 1703 The first Eddystone Lighthouse destroyed in 1971. The descent module entered the Martian atmosphere at roughly 6.0 km/s at a steeper angle than planned. The descent system malfunctioned and the lander crashed at 45 deg S, 302 deg W, delivering the Soviet Union coat of arms to the surface. Meanwhile, the orbiter engine performed a burn to put the spacecraft into a 1380 x 24,940 km, 18 hour orbit about Mars with an inclination of 48.9 degrees. Scientific instruments were generally turned on for about 30 minutes near periapsis.
Mars 3's descent module was released at 09:14 UT on December 2December 2 is the 336th day (337th on leap years) of the year in the Gregorian calendar. There are 29 days remaining. Events 1409 The University of Leipzig opened. 1755 The second Eddystone Lighthouse is destroyed by fire. 1804 At Notre Dame Cathedral in 1971, 4 hours 35 minutes before reaching Mars. The descent module entered the Martian atmosphere at roughly 5.7 km/s. Through aerodynamic braking, parachutes, and retro-rockets, the lander achieved a soft landing at 45 S, 158 W and began operations. However, after 20 seconds the instruments stopped working for unknown reasons, perhaps as a result of the massive surface dust storms raging at the time of landing. Meanwhile, the orbiter had 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 long 12 day, 19 hour period orbit about Mars with an inclination thought to be similar to that of Mars 2 (48.9 degrees).
The Mars 2 and 3 orbiters sent back a large volume of data covering the period from December 1971 to March 1972, although transmissions continued through August. It was announced that Mars 2 and 3 had completed their missions by 22 August 1972, after 362 orbits completed by Mars 2 and 20 orbits by Mars 3. The probes sent back a total of 60 pictures. The images and data enabled creation of surface relief maps, and gave information on the Martian gravity and magnetic fields.