Probes have been visiting Venus since the earliest days of the Space Age.
In fact, Venus was the first planet to be visited by a probe. The Russians launched a probe toward Venus in 1961, but it was the U.S. probe Mariner 2 that took the first measurements.
However, approaching Venus presents major challenges. The sunlight is almost twice as strong as it is on Earth, so it is necessary to cool the craft to prevent its instruments from being destroyed by the heat. And the problems intensify when astronomers attempt to land their instruments on the surface.
The atmosphere is dense and filled with carbon dioxide, a combination that generates a greenhouse effect and can create surface temperatures of up to 900 degrees F. Additionally, the pressure is 90 times the level on Earth’s surface. Such extreme conditions make it difficult for a landing craft to work for even an hour.
These challenges are about to be overcome, however, as astronomers are now able to study the surface of Venus without landing. Scientists can use radar to create maps, and space probes such as Venus Express (which is presently orbiting the planet) can “see” the surface to some extent by observing it at particular wavelengths. The next step will likely be to send balloons
to drift through the dense cloud layer surrounding the planet. This will allow scientists to test the theory that microorganisms could be living in the cloud layer, where the temperature is much lower than on the surface.