The Soviet Union launched numerous spacecraft to investigate Mars between 1960 and 1988. Some of these missions were partial successes, while others failed. By and large, the Soviets were much more successful exploring Venus than the "Red Planet."
The Soviets launching at least seven missions to Mars during the 1960's. They all failed. The vehicles were either destroyed during launch, were unable to leave Earth orbit, or suffered catastrophic failures en route.
In 1971, the Soviets launched twin Mars 2 and 3 spacecraft to the Red Planet. Each spacecraft included an orbiter and lander. Unfortunately, they arrived at the planet at the height of the largest dust storm ever recorded by astronomers. The spacecraft lacked enough fuel to place the entire assembly into orbit. As a result, they were forced to release the landers on schedule (before orbital insertion) instead of waiting until the storm cleared. The Mars 3 probe successfully landed on the surface, making it the first man-made object to achieve this goal. However, it stopped transmitting 20 seconds after the television scan began. The Mars 2 probe failed after its breaking rockets malfunctioned.
The orbiters successfully entered orbit around Mars and made observations of the planet and its environment. The Mars 2 orbiter returned data until 1972. The Mars 3 orbiter ceased functioning in August 1972, after making measurements of surface temperature and atmospheric composition.
The USSR launched four spacecraft in 1973. Mars 4 and 5 were designed as orbiters, and Mars 6 and 7 were designed to drop landers onto the planet. Mars 5 entered orbit around the Red Planet on February 12, 1974, returning pictures and data for no more than 10 days. The Mars 6 probe entered the atmosphere and returned about 150 seconds of data during the descent. The instrumentation helped to refine estimates of air density and composition. However, the lander failed just prior to touchdown.
The other two spacecraft failed. Mars 4 experienced an engine failure that caused it to miss the planet and enter solar orbit. It flew past the planet at a distance of 2,200 kilometers (1,370 miles) and returned some images and data. Mars 7 missed the planet entirely and went into solar orbit.
After the Mars series was completed, the Soviets didn't launch any spacecraft to the planet for 15 years. During this period, they concentrated their attention on a series of increasingly sophisticated, and largely successful, missions to Venus.
In July 1988, the nation launched the Phobos 1 and 2 missions in a bold effort to investigate Mars and its small moon, Phobos. This was one of the most innovative planetary missions ever attempted, involving the first close scientific investigation of and landing on another planet's moon.
Some scientists believe that Phobos, and the other Martian moon Deimos, are captured asteroids. Scientists are interested in knowing how asteroids formed and what that can reveal about the creation of the solar system. In addition to studying Phobos, the spacecrafts were designed to take photographs and measurements of Mars and its environment.
The two spacecraft were to have entered Martian orbit and then gradually manuevered toward Phobos, flying to within 31 to 62 meters (100 to 200 feet) of the surface. The spacecraft would use a laser instrument to vaporize small parts of the surface. The vapors would be measured to determine the chemical composition of the surface. Another instrument would measure the composition by emitting a concentrated beam of krypton particles. A mass spectrometer would have measured the particles given off by the surface material.
The most interesting aspect of the mission involved two landers that each spacecraft was to have released. The larger lander included a camera, a surface penetrator, and other instruments to measure the surface of Phobos. Because the moon's gravity is so small, a harpoon-like object would be driven into the surface to keep the probe from drifting back into orbit. The smaller lander, which weighed 50 kilograms (110 pounds), had spring-loaded legs that would allow it to hop around the surface. The lander would make chemical, magnetic and gravity observations at different locations.
The mission was the most international planetary program ever run by the Soviet Union. It included equipment, cameras and instruments from 14 nations. Participants included the European Space Agency and individual European nations such as Austria, France, Sweden, Switzerland, and West Germany. The United States government allowed American scientists to serve as advisors and contributed the use of its Deep Space Network for tracking the twin spacecraft. As a result, scientists in many nations eagerly awaited the results.
Unfortunately, they were deeply disappointed. Phobos 1 was lost on September 2, 1988, when a controller sent the wrong command to the spacecraft's computer. Phobos 1 became disoriented and lost its lock on the sun. The solar cells could not function properly and the probe lost power.
Phobos 2 entered Martian orbit on January 30, 1989, and began making observations of Mars and Phobos. However, it failed after moving within 800 kilometers (500 miles) of Phobos. Controllers believe that an on-board computer malfuction resulted in a failure of orientation control, thus exhausting the craft's energy supply. The landers were never released.
The Soviet Union collapsed at the end of 1991. The Russian government has attempted to continue an ambitious set of Mars exploration projects planned during the final years of the USSR. The missions include orbiters, balloons, surface penetrators, and rovers. During this period, the Russians have stepped up efforts to cooperate with the United States, European countries, and other foreign governments.
Russia will launch the ambitious Mars '96 mission at the end of 1996. This spacecraft consists of an orbiter and four landers that will explore the Martian environment. The orbiter will use 12 instruments to map the Martian surface, monitor the climate and atmosphere, investigate the plasma field, and perform other scientific investigations. The surface element consists of two soft landers that will study the environment and two penetrators that will examine the regolith.
Planetary Science Database, National Space Science Data Center (NSSDC), National Aeronautics and Space Administration, Greenbelt, Maryland, USA. World Wide Web: http://nssdc.gsfc.nasa.gov/nssdc/nssdc_home.html.
Space Research Institute, Russian Academy of Sciences, Moscow, Russia. World Wide Web: http://www.iki.rssi.ru/
Wilford, John Noble, Mars Beckons, Alfred A. Knopf, New York, 1990.