The Us Missions To Mars
...For its time, Mariner 4 was an amazing piece of equipment. Its basic structure was an eight-sided magnesium framework with seven electronics compartments. Four solar panels were attached to the top or sunward side of the octagon, which collected sunlight for electrical power. It contained a television camera and six other instruments, which were hoped to be used to measure conditions in space and near Mars. The instruments included radiometers, spectrometers, magnetometers, and a cosmic dust collector. The mission of Mariner 4 was to perform a simple flyby of Mars, instead of going into a complicated insertion orbit around the planet. On July 14, 1965 Mariner 4 flew over Mars at a distance of about 6,118 miles. The probe radioed back to Earth 22 television images covering approximately one percent of Mars’ surface. The blurry black-and-white images caused a stir among NASA scientists and astronomers. The surface of Mars was not at all what they expected it to be. They were expecting vegetation and water; instead they were greeted with a wasteland filled with craters, which had a great resemblance to our Moon. Mariner 4 did not detect a magnetic field surrounding Mars, which meant it did not have a big metallic core like Earth. This meant bad news for future human astronauts since cosmic radiation would be about 100 times greater than on Earth. Mariner 4’s instruments also provided scientists with the information that the atmospheric pressure on Mars is only between one and two percent that of Earth. The little atmosphere there is on Mars was detected to be mostly carbon dioxide. Liquid water could almost certainly not exist on Mars since it would quickly evaporate in the thin Marian air. Mariner 4 lasted about three years in solar orbit, much longer then was expected of the probe. Scientists were a little let down by what Mariner 4 showed them:...
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