Red Bull STRATOS science team reveals supersonic freefall technicalities

RED BULL STRATOS SCIENCE TEAM REVEALS SUPERSONIC FREEFALL TECHNICALITIES
At 120,000 Feet above Sea Level, Altitude Is Both Ally and Adversary

Dubai, 09 March 2010

Red Bull Stratos science team released the first new information available since Felix Baumgartner’s mission to the edge of space was announced to the public on January 22, 2010. The detail offered provides deeper insight into how and why Baumgartner hopes to become the first person ever to “go supersonic” in freefall as he attempts a sky dive from a stratospheric balloon.

The speed of sound varies according to altitude and temperature. The Red Bull Stratos science team estimates that – after only about 35 seconds of freefall – Baumgartner will break through the sound barrier and “catch up with” the speed of sound, which is likely to be about 690 miles per hour at the predicted altitude of 100,000 feet. Known hazards at such altitudes include temperatures well below zero; unpredictable factors compounding those dangers include sudden changes in air pressure and resulting instability in the “transonic” zone (speeds approaching supersonic velocity), which in the mid-twentieth century caused aircraft to go out of control or break up and resulted in the concept of a sound “barrier

“Our biggest concern is that we don’t know how a human unencumbered by an aircraft is going to transition through this,” says Dr. Jonathan Clark, the mission’s Medical Director. “But it’s also exactly what we’re hoping to learn, for the benefit of future space flights.”

Einar Enevoldson, who set eight world records during his own career as a research pilot and is now the Red Bull Stratos Mission Analyst and Safety Advisor, adds, “One of our primary goals is to determine a test and safety plan that will protect Felix Baumgartner from the effects of extreme pressures or temperatures, yet will result in a very valuable step toward predicting the character of these effects in potential future higher and faster jumps.”

The Red Bull Stratos mission plan to achieve supersonic flight in freefall considers a wide range of factors, including “terminal velocity” (a concept familiar to skydivers at moderate altitudes), which can be explained in an elementary fashion as the speed at which the wind resistance on a jumper equals his or her weight, halting further acceleration. Jumping from an altitude of 120,000 feet, in very thin air (less than 1 percent of the density on the ground), the level of wind resistance on Baumgartner should be extremely small, and calculations indicate that if he can reduce drag by streamlining his body position, attaining the speed of sound is possible.

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