Pioneer Venus

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Venus is our closest planetary neighbor, but it's hard to touch. Surface temperatures are more than 850 degrees Fahrenheit, and atmospheric pressure is 90 times greater than on Earth. And clouds of sulfuric acid blanket the planet, hiding the surface from sight.

In fact, in more than half a century of missions to Venus, the United States has sent only one that was designed to penetrate the clouds and drop toward the surface. That mission arrived at Venus 30 years ago today.

Pioneer Venus 2 consisted of a main spacecraft plus several small probes. The spacecraft burned up as it entered the atmosphere, but the probes parachuted to the surface. They compiled a profile of the atmosphere all the way down -- temperature, pressure, and composition. They found hazy skies at high altitudes, but clear skies below about 20 miles.

Pioneer Venus 1 had entered orbit around Venus just five days earlier. It was the first mission to use radar to peer through the clouds and map Venus's surface. It operated for almost 14 years -- longer than any other planetary orbiter to date.

Pioneer's target -- the hard-to-touch planet Venus -- is in good view the next few months. It's the brilliant "evening star." It stands in the southwest at nightfall, and sets by mid-evening. The not-quite-as-bright planet Jupiter is to its lower right. It sets a little earlier than Venus, but it'll remain in view until around the first of the year.

Script by Damond Benningfield, Copyright 2008

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