peter Posted March 15 Share Posted March 15 9 hours ago, SimonTV said: Jonathan Clark Associate Professor of Neurology and Space Medicine at Baylor College of Medicine, who worked at NASA from 1997 to 2005 and was a six-time Space Shuttle crew surgeon Speed is just a distance-per-time-unit measure, so the constraints to speed are really dependent on other environmental factors. The velocity isn’t the issue as much as the change in velocity, which is acceleration. When you go to space, you have to get enough speed to get out of Earth’s gravity field. To get to lower orbit, astronauts have to get to 17,500 miles per hour, and to do that they have to change their velocity. They launch such that they’re taking the gravity from the front of their chest to the back of their chest—that’s called the G direction. Typically, the best way to tolerate it is going from front to back, which is why astronauts launch on a couch, sitting down. The other constraint of velocity is in the atmosphere. John Paul Stapp, when he did his sled run, got up to 46, 47 Gs, and he was probably going close to 5 or 600 miles an hour. If you looked at his face, you would see that it was being blown and heavily distorted, and that his hands were actually restrained on his lap so they wouldn’t flail around. Speed going through an atmosphere causes what’s called aerodynamic flail, and that can kill you. When you’re in outer space you can go as fast as you want—but you need the protection of a vehicle, or a pressure suit, to keep you from the exposure to the vacuum of space. We know that humans have gone 25,000 miles per hour going to the moon—the speed itself is not an issue, it was mainly the acceleration to get out of the Earth’s atmosphere that they had to endure. Once they’re on their way and speeding up, there’s no constraints to speed. We’ll eventually send humans to mars and they’ll be going 35,000 miles per hour. The two programs I was involved with, the Red Bull Stratus and the space dive—the goal was for a human without a vehicle to break the speed of sound, and that was accomplished because they wore a pressure suit. The reason they didn’t have aerodynamic flail issues was that there’s very little atmosphere above a hundred thousand feet You can attain very high speeds—at least supersonic ones—as long as you’re protected, or (if you’re free falling from space) you’re at an atmospheric density that’s not going to cause that flail to develop. like I said with your other post ,your point is? Quote Link to comment Share on other sites More sharing options...
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