Mars 3
Mars 3 Orbiter
|
|
| Mission type | orbiter and lander |
|---|---|
| Operator |
 Soviet Union
|
| COSPAR ID | Orbiter:1971-049A Lander:1971-049C |
| SATCAT no. | Orbiter:5252 Lander:5667 |
| Mission duration | Orbiter:452 |
| Spacecraft properties | |
| Launch mass | Orbiter:2,265 kg (4,993 lb) Lander:358 kg (789 lb) |
| Start of mission | |
| Launch date | 15:26:30, May 28, 1971 |
| Rocket | Proton-K with Blok D upper stage |
| End of mission | |
| Disposal | Decommissioned |
| Deactivated | August 22, 1972 |
| Orbital parameters | |
| Reference system | Areocentric |
| Mars orbiter | |
| Orbital insertion | December 2, 1971 |
| Orbit parameters | |
| Periareion | 1,500 km (930 mi) |
| Apoareion | 211,400 km (131,400 mi) |
| Inclination | 60° |
| Mars lander | |
| Spacecraft component | Mars 3 Lander |
| Landing date | December 2, 1971 (11 Libra 192 Darian) 13:52 UTC SCET (MSD 34809 03:06 AMT) |
| Landing site | 45°S 202°E / 45°S 202°E (predicted) |
Mars 3 was an unmanned space probe of the Soviet Mars program which spanned the years between 1960 and 1973. Mars 3 was launched May 28, 1971, nine days after its twin spacecraft Mars 2. The probes were identical robotic spacecraft, each consisting of an orbiter and an attached lander. After the Mars 2 lander crashed on the martian surface, Mars 3 lander became the first spacecraft to attain soft landing on Mars. Both probes were launched by Proton-K rockets with Blok D upper stages.
The primary purpose of the orbiter was to study the topography of the surface; analyze its soil composition; measure various properties of the atmosphere; monitor "solar radiation, the solar wind, and the interplanetary and martian magnetic fields." In addition, it served as a "communications relay to send signals from the lander to Earth."
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 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 scientists were surprised to find the 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.
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 22 August 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 km, atomic hydrogen and oxygen in the upper atmosphere, surface temperatures ranging from −110 °C to +13 °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 km altitude, and grains from dust storms as high as 7 km in the atmosphere. The images and data enabled creation of surface relief maps, and gave information on the Martian gravity and magnetic fields.
...
Wikipedia