Project Stratos vs. Project Excelsior: Breaking the Sound Barrier in Freefall

By Norman Chan

The highest parachute jump ever performed was at 102,800 feet over 50 years ago. That record may finally be broken.

Since early 2010, Austrian skydiver Felix Baumgartner has been trying to break the speed of sound. Not by flying in a supersonic jet but by jumping out of a balloon at an elevation of over 100,000 feet. Baumgartner wants to be the first man to experience freefall from the edge of space. To help him achieve that goal, energy drink company Red Bull--no stranger to sponsoring extreme aerial projects--set up Project Stratos to break the freefall record set by Joseph Kittinger in 1960, when the US Air Force pilot made a historic 102,800 foot jump from a high-altitude balloon. But due to lawsuits, the project stalled in 2010, delaying the scheduled jump from 2011 to late this year. Red Bull and Baumgarnter have begun resuming test jumps, with the most recent trial from 71,000 feet. In the tests, Baumgartner reached a speed of over 360 miles per hour, spending almost four minutes in freefall. Still, that's less than half the speed of sound (768 miles per hour at sea level but lower at high altitudes), and at an altitude that's much shorter than the eventual goal of 120,000 feet. (At 100,000 feet, just 30 seconds of freefall can accelerate you to 690 miles per hour, the speed of sound at that height.)

Photo Credit: Redbull Stratos

To endure the atmospheric conditions of freefall at those insane heights, Project Stratos has developed a special pressure-suit for Baumgartner to wear. Engineered by a company that makes pressure suits for NASA, the Mach-1 suit looks like a slimmed down space suit and is equipped with advanced pressure systems, g-force meters, and insulators that will keep Baumgartner stable as he creates shock waves while passing through the sound barrier. That's in addition to the sensors that will collect valuable scientific data for researchers to analyze for future space programs. It's a far cry from the technology available to Kittinger when he made his jump over 50 years ago in Project Excelsior, though the retired pilot is advising in Project Stratos to help Baumgartner make his jump.

Here's how the gear Felix Baumgartner will be using for his space dive later this year compares to what Joseph Kittinger had at his disposal back in 1960.

Photo Credit: US Air Force

Project Excelsior

  • Kittinger wore a full-pressure suit that was a modified Air Force MC-3 partial pressure suit covered by winter coveralls. If the suit was breached, Kittinger would be unconscious in 10 seconds and dead in minutes.
  • Along with additional layers of heavy insulation, Kittinger also had to carry a box with oxygen, instruments, and cameras. His total weight was 320 pounds.
  • The parachute used was a multi-stage system developed at Wright-Patterson Air Force Base, involving a 6 ft drogue chute to prevent uncontrollable spinning (up to 200rpm) and a 28 ft main chute deployed at lower altitude.
  • Altitude sensors automatically deployed both chutes at pre-programmed points, in case Kittinger fell unconscious.
  • The Excelsior gondola was built by Winzen Research, and was an open frame 56 inches in diameter and 40 inches tall, made of steel. The balloon also had a 40-ft diameter parachute in case the balloon malfunctioned.
  • To lift the gondola to altitudes above 100,000 feet, the balloon used 3 million cubic feet of helium.
  • Excelsior included test flights of 76,400 feet and 74,700 feet before the final jump of 102,800 feet.
  • Temperature dropped to below 94° F during the jump.
  • Top speed reached was 614 miles per hour.
  • Time of descent was 13 minutes and 45 seconds.
Photo Credit: Redbull Stratos

Project Stratos

  • Baumgartner's suit is made of four layers, which act as insulators and also makes it rigid during the fall. A pressure system will keep internal pressure at 3.5 PSI.
  • The parachute system includes a drogue chute, main chute, and reserve chute. Both the main and reserve chutes are over two times as large as typical 9-cell designs. For safety, Baumgartner will also have access to four release handles to free himself from the parachutes in case a jettison is needed.
  • The helmet sports a plastic-composite faceplate with heating wires on the inside to prevent breath crystallizing from the cold temperature.
  • A G-force meter can trigger the parachutes if Baumgartner experiences a force of 3.5Gs for more than six seconds.
  • Other equipment include a 12 pound chest pack for monitoring, tracking, and communications systems to send back to mission control in real time.
  • Fully loaded, Baumgartner will weigh 260 pounds.
  • Unlike Excelsior's open Gondola, the dive will take place from a pressurized space capsule lifted by a helium balloon. In addition to being enclosed and pressurized, the capsule is also heated.
  • The capsule's frame is made of chrome molybdenum steel, the same material used in stock cars, and the actual capsule itself is a 6-ft diameter fiberglass sphere.
  • Ascent will take three hours to reach the target 120,000 feet.

Here's an awesome montage of video shot from Project Excelsior.