Moon and Venus 
At a depth of 3,000 feet, Earth’s oceans are a no-man’s land. The water exerts a pressure of almost 1400 pounds per square inch — enough to crush the hulls of all but the sturdiest of submarines. That environment is more difficult to operate in than the surface of the Moon is.
A similar environment faces explorers on the surface of Venus. It’s not water that’s pressing down, though, but the planet’s thick atmosphere. It’s about 90 times thicker than Earth’s atmosphere — the equivalent of an ocean depth of about 3,000 feet. That’s a tough place for even robotic probes to explore.
And it’s made even tougher by the temperature — more than 850 degrees Fahrenheit. That’s also a result of the atmosphere, which is made mainly of carbon dioxide. It traps heat from the Sun, turning the planet’s surface into a high-temperature oven.
Only a few probes have managed to survive these conditions — almost all of them sent decades ago by the Soviet Union. They showed a surface of rocks and dirt under a dim sky colored orange by a thick blanket of clouds.
Yet none of these hardy explorers lasted long — they all succumbed within about an hour. So exploring Venus for longer periods will require a lot of innovation — providing protection from an environment that’s even less forgiving than the ocean depths.
Venus is in good view not long after sunset. It’s the brilliant “evening star,” close to the upper right of the Moon. More about Venus and the Moon tomorrow.
Script by Damond Benningfield, Copyright 2013