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Consequently, the capsule was designed to survive 300C and 25 bars. This was in line with what was then assumed to be the surface conditions.Īt the time, it was thought that the surface temperature of Venus was approximately 300C, with an atmosphere consisting mainly of carbon dioxide and nitrogen at about 20 bars. The early Venera probe hulls were designed for an atmospheric pressure of 25 bar. When did scientists first realize that landers would need to withstand such pressures to survive there? These are all hypothetical, but I'm interested in the facts.
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We can't see through the atmosphere in visible light, but that's so much material that the index of refraction would slow down precision interplanetary radar, so it's possible that careful timing of radar signals, along with a good ephemeris and understanding of Venus' period could detect it, but there were also some early spacecraft that may have sent telemetry, and those would have measurable ranges as well, so without a local altimeter, you still could know it's approximate distance from the surface. So I'd like to ask what were the earliest observations that led to planetary scientists to know that the pressure was so huge that it wasn't 2x or 5x or even 20x Earth's, but that it was almost 100x? Of course in reality its much more complicated. If you piled on 99 times more N2/O2 on Earth, then at least for a short while, the pressure here would be roughly like that of Venus. So what makes Venus' atmospheric pressure at the surface almost 100x larger than Earth's is (to 0th order) that there's almost 100x more of it. Very basic physics of atmospheres says that the pressure at a given height supports the weight of the atmosphere above it, and this gives an exponential behavior for a constant temperature, and can be calculated even for variable temperatures. Wikipedia states that Venus' atmospheric pressure at the surface is about 93 bar (93 times Earths' atmospheric pressure at sea level), which it says is like being roughly 900 meters below the surface of the ocean.
#Venus scrolling led badge plus
That plus comments below this answer got me thinking first about just how large the pressure is on the surface of Venus, and then "how did they first find out?"
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The question Surface of Venus - what would it look like to see a spacecraft crushed by the atmospheric pressure? is a good one!