High-altitude military parachuting

[4] In 1960, the United States Air Force began conducting experiments that followed earlier work by Colonel John Stapp in the late 1940s[5] through early 1950s on survivability for pilots ejecting at high altitude.

Stapp also solved many of the problems of high-altitude flight in his earliest work for the U.S. Air Force and subjected himself to exposure to altitudes of up to 45,000 feet (14,000 m).

As part of the experiments, on August 16, 1960, Colonel Joseph Kittinger performed the first high-altitude jump at 19.5 miles (31.4 km) above the Earth's surface.

SEAL Teams of the United States Navy expanded the HALO technique to include delivery of boats and other large items.

The technique is used to airdrop supplies, equipment, or personnel at high altitudes, where aircraft can fly above surface-to-air missile (SAM) engagement levels through enemy skies without posing a threat to the transport or load.

In a typical HALO exercise, the parachutist will jump from the aircraft, free-fall for a period of time at terminal velocity, and open their parachute at an altitude as low as 3,000 feet (910 m) AGL depending on the mission.

The HAHO technique is used to airdrop personnel at high altitudes when aircraft are unable to fly above enemy skies without posing a threat to the jumpers.

The jumper must use way points and terrain features to navigate to their desired landing zone and correct their course to account for changes in wind speed and direction.

[8] The transition into being military free-fall certified starts with successfully completing the static-line certification at Fort Moore, Georgia.

Rapid ascent in the jump aircraft without flushing sufficient nitrogen from the bloodstream and other body tissues can lead to decompression sickness, also known as caisson disease or "the bends".

A typical HAHO exercise will require a pre-breathing period (30–45 minutes) prior to jump where the jumper breathes 100% oxygen in order to flush nitrogen from their bloodstream.

[citation needed] In addition, problems with the oxygen bottle and during the changeover from the pre-breather to the oxygen bottle can result in the return of nitrogen to the jumper's bloodstream and, therefore, an increased likelihood of decompression sickness [clarification needed][9] A jumper suffering from hypoxia may lose consciousness and therefore be unable to open the parachute.