John B quote "I'm not sure that too amny parachutes would be needed. The factor not mentioned so far is "Terminal Velocity". For all practical purposes, it doesn't matter if you jump from 500 feet or 5,000 feet. The Terminal Velocity is the same, about 120 mph if in a spreadeagled position."
Hi John, the terminal velocity is giverned by mass/surface area presented to atmosphere. Higher altitude = less density of atmosphere, therefore higher speed. Your figure would be at around sea level. Kittinger, Joseph W, Jr. "The Long, Lonely Leap." National Geographic. December 1960: 854-873.
"An hour and thirty-one minutes after launch, my pressure altimeter halts at 103,300 feet. At ground control the radar altimeters also have stopped-on readings of 102,800 feet, the figure that we later agree upon as the more reliable. It is 7 o'clock in the morning, and I have reached float altitude …. Though my stabilization chute opens at 96,000 feet, I accelerate for 6,000 feet more before hitting a peak of 614 miles an hour, nine-tenths the speed of sound at my altitude."
Hope this helps.
