Robot Explorers: US Unmanned Space Missions: page 7 |
Throughout the 1960's, our planetary visits were limited to our own neighborhood, so to speak. But in 1972, NASA dispatched the first of four spacecraft designed to survey the giant planets in the outer solar system. |
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| Pioneer 10, which lifted off from Kennedy Space center in
March of 1972 was the first spacecraft to penetrate the asteroid belt and travel to the
outer regions of the solar system. The spacecraft passed by Jupiter within 81,000 miles of
the planet in December of 1973. During its passage Pioneer 10 obtained the first close-up
images of the planet and charted its intense radiation belts. Pioneer 10 is now 7.9 billion miles away. It was tracked for 7.6 billion miles. Originally designed to last for 21 months, Pioneer 10 lasted for over 30 years! The last transmission from this craft was received in January of 2003. |
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Pioneer 11 lifted off from Kennedy Space Center in 1973, its destination both Jupiter and Saturn. This was the first craft to use "gravitational assist". By flying close enough to Jupiter to be influenced by the planet's gravitational pull, and by approaching the planet at the proper angle, Pioneer 11 was able to alter the direction of its orbit and gain the momentum needed to "sling-shot" it on to Saturn. |
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The first close-up images of Saturn and its ring system
were returned from this mission. In the next two years, both Voyagers 1 and 2 would follow, sending back truly breathtaking images of Saturn's complex ring system. |
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Copyright ©2004 Colleen Gino |
Images courtesy JPL and NASA. |
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