Past Mars Missions: An International Affair
Attempts to explore the Red Planet have been marked by numerous failures, particularly in the first decade of the space age. What follows is a brief overview of the missions in chronological order. It shows the problems in space exploration and the perseverance of Russian, American, Japanese, European and Canadian researchers, who have been sending probes and devices to Mars for over 40 years.
The Race to Mars in the 1970s and 1980s
May 9 – Mariner 8, successor to Mariner 3 (1964), re-enters Earth's atmosphere shortly after launch as a result of launch problems. The probe falls into the Atlantic Ocean, 560 km north of Puerto Rico. Its mission was to orbit Mars and return images.
May 10 – The race between the Americans and Soviets heats up. Cosmos 419, a Soviet orbiter, tries to overtake the Mariner 8 probe, launched by the United States a day earlier. The spacecraft has onboard an instrument supplied by France that measures solar radiation. The spacecraft fails to function because of an error in the ignition-timer setting: it was programmed to start ignition 1.5 years after orbit, rather than 1.5 hours. Cosmos 419 re-enters the atmosphere a few days later.
After 1962, the name Cosmos was given to Soviet spacecraft that remained in orbit around Earth, regardless of their intended destination. Soviet interplanetary missions were initially put into an Earth parking orbit as launch platforms. The probes were then launched on their trajectory with an engine burn. If the engine misfired, the probes would stay in Earth orbit and be renamed Cosmos.
May 19 and 28 – Identical probes, Mars 2 and Mars 3, are launched by the Soviets a few days apart. They are to return images of the surface and clouds of Mars, determine the planet's temperature, and record solar winds. Each orbiter is equipped with a lander. Although there are problems with the landers, the two orbiters return a significant amount of data until the end of their mission in 1972.
May 30 – Mariner 9 revolutionizes scientific theories about the geography of Mars; it was considered for a long time to be similar to our Moon, with craters and an environment hostile to forms of life. In early 1972, following a long dust storm, Mariner 9 reveals a geological universe completely different to that imaged in previous missions. The probe returns 7,329 photos during its mission, which ended on October 27, 1972. The spacecraft orbits the planet and is not expected to enter the Martian atmosphere before 2024.
Although the Soviet mission Mars 4 does not produce the expected results, it does return new data on the Red Planet, including the first on the night-side ionosphere of Mars. Rockets that were to slow Mars 4 on its approach to Mars do not fire and the spacecraft flies past its target at a range of 2,200 km. After the flyby, the probe continues to return data, orbiting the Sun.
Unlike its predecessor, Mars 5 successfully enters Mars orbit and returns more than 60 images to Earth over nine days. However, pressurization loss prevents the probe from continuing its mission.
The results of the Mars 6 mission, launched in the same year, are no better than those of Mars 4; radio communication with the lander is lost 224 seconds after it enters the Martian atmosphere. Despite its problems, this mission goes down in interplanetary exploration history because it returns the first data from the surface of Mars.
The Mars 7 orbiter misses its target when its lander separates from the orbiter four hours early, missing the planet by 1,300 km. The orbiter and lander now orbit the Sun.
The American orbiters Viking 1 and 2 each have a lander aboard. Viking 1 is the first spacecraft to successfully land on Mars. The images reveal to the world a land of volcanoes, plains, immense canyons, craters, wind-formed features, and evidence of past surface water. Orbiters Viking 1 and Viking 2 provide a better understanding of the composition of the planet's core.
The Quiet 1980s
Soviet probes Phobos 1 and 2 are developed to study Phobos, one of the Martian moons, which may be an asteroid captured by the planet's gravity field. Each probe has two landing units. Mid-journey, the guidance computer of Phobos 1 experiences problems interpreting commands which results in a depletion of the spacecraft's power reserve. Phobos 2 returns a number of interesting images of the Martian moon during its two months in orbit. However, an attempt to release its two landing units fails, depleting its fuel reserve.
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