The Science Behind Felix Baumgartner's 128,000 Foot Skydive

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Images: SoldWorks

When Felix Baumgartner dove out of a capsule head first at the edge of space over 24 miles above Earth, he didn’t just have technology helping him break the world record, he had science on his side.

These days, when daredevils attempt death defying feats like leaping from the edge of the atmosphere, they don’t just execute several test jumps, they also run computer simulations to figure out how to not only break the record, but to get safely back to terra firma.

Those simulations can look like these from SolidWorks, using sophisticated software that not only takes into account all the mathematical probabilities of a jump that high, but also show, in vivid detail, the physics and the physical forces that are working on his body as he plummets earthward. Using these simulations before his jump proves why Felix had to stay in a head down position in order to break the sound barrier.

The full article by Dr. Stephen Endersby from SolidWorks gives all the math and equations involved, but the basic problem was which would come first, the sound barrier or terminal velocity? Taking the opposing forces on Felix’s body — the accelerating force vs. the retarding drag — Dr. Endersby found that at 25 seconds of free fall from a height of 120,000 feet, Felix would still be accelerating.

At 32.5 seconds, Dr. Endersby’s calculations without factoring in air resistance (marked “Simple Freefall” on the chart) said Felix should reach supersonic speeds. But after running repeated computer model simulations, he found that air resistance keeps Felix from reaching Mach 1.

With this data, they discovered two things: 1. To have the time necessary to generate enough speed, Felix needed to jump from higher than 120,000 feet, and 2. He would need to angle his body head down in order to reduce the retarding drag on his body.

Felix did both, adding 8,000 feet to the jump, and diving head first, becoming the first person to break the speed of sound outside of vehicle, hitting a speed of an incredible 834 mph. If they had run high school Physics classes like this, I might have paid more attention.

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