"Fearless Felix" approaches speed of sound in second Red Bull Stratos jump
By Brian Dodson
July 25, 2012
Skydiver "Fearless Felix" Baumgartner has done it again - successfully carrying out an 18.3 mile (29.5 km) skydive from the Red Bull Stratos balloon high above Roswell, NM. His top speed was 536 mph (865 km/h). At that altitude, the speed of sound is about 673 mph (1083 km/h), so Baumgartner's top speed was Mach 0.80!
Early this morning, Baumgartner, wearing a fully pressurized space suit, climbed into an eight-foot (2.4 m) diameter pressurized capsule to await launch for his second test jump.
The capsule hung about 150 feet (46 m) below a 600-foot (183 m) helium-filled balloon. After launch, it took about an hour and a half to reach the jump altitude. Although this flight was intended for a 90,000 foot (27.4 km) jump, this goal was overshot, resulting in a jump from 96,640 feet (29.5 km).
Prior to and during the 90-minute ascent, Baumgartner was breathing the capsule's eight psi (55 kPa) pure oxygen atmosphere, equivalent to air pressure at 15,000 feet (4.6 km). These conditions help to prevent the bends (formation of nitrogen bubbles in the bloodstream), should the capsule or his space suit be breached. The reduced pressure and the long period of breathing pure oxygen reduce the amount of dissolved nitrogen as well as the pressure change involved in becoming exposed to the near-vacuum in the upper stratosphere.
After jumping, his space suit life support systems took over, maintaining a pure oxygen pressure of eight psi (55 kPa) from two bottles of oxygen gas attached to his spacesuit.
The air pressure when he left the capsule was about one percent of sea level, meaning that his blood would boil without the protection of his space suit. After an estimated free fall of three minutes and 48 seconds, he triggered his parachutes, and landed outside of Roswell ten minutes and 36 seconds after he jumped from the capsule. The capsule descended to Earth on its own parachute system for reuse.
The Red Bull Stratos project is aimed at carrying out a freefall jump from an altitude of 120,000 feet, breaking the sound barrier during the descent. NASA is paying close attention to these jumps, wanting to apply the Stratos lessons to potential escape systems for future spaceships.
The final Stratos jump is scheduled for late August or early September.
Source: Red Bull Stratos