AST 111 Lecture Notes - Lecture 25: Pioneer Venus Orbiter, Tunxis Community College, Pioneer 1
18 Dec 2020
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Document Summary
Almost circular orbit with sidereal orbital period of 225 days. Its surface is shrouded by heavy clouds. We have been bouncing radar signals off of it since 1961. It rotates backwards, with a sidereal rotation period of 243 days. It vertical axis is tilted 171 degrees, and because it is greater than 90, it is retrograde. Since 1962, 19 spacecraft from u. s. and russia have visited. Soviet union landed 11, which took close photos of surface. Photos of sharp rocks confirm that winds are calm. Pioneer venus 1 and magellan- have recorded detailed radar maps of surface. 2/3 of surface are rolling hills, with highlands less than 10 percent, and the rest are lowlands. It has 1000 craters that are large than a few km in diameter. None of the craters are older than 800 million. Average surface age is estimated at 500 million (twice as old as earth"s)
