The Austrian daredevil Felix Baumgartner will make a death-defying leap from the edge of space on Tuesday - weather permitting - as he attempts to complete the highest, fastest skydive in history. Baumgartner, 43, will jump from a helium-filled balloon 23 miles above the Earth's surface, three times the altitude of a cruising airliner.
On his way down, the man nicknamed Fearless Felix will become the first human to break the sound barrier without the aid of an aircraft if - as one of his crew said - his blood does not bubble and his eyes do not haemorrhage.
Cameras will be attached to Baumgartner's specially designed pressure suit and live footage of his descent will be broadcast on the internet. The former military parachutist has said he wants to "share" the experience with the world, and is confident all will go according to plan. During his jump, over desert in the US state of New Mexico, temperatures will be as low as -69F (-56C). If his suit rips, potentially lethal bubbles could form in Baumgartner's blood. If he loses control and goes into a flat spin, he risks blood vessels bursting in his eyes and brain.
Baumgartner previously became the first person to skydive across the English Channel in 2003. He jumped from a plane over Dover and used a 6ft carbon wing to help him glide across to France.
He has also parachuted off the Petronas Towers in Kuala Lumpur, and the statue of Christ the Redeemer in Rio de Janeiro. The space jump was originally scheduled for Monday but was postponed because of the weather. The 700ft balloon being used to take him up can only be launched if winds on the ground are less than 2mph.
Planning for the jump has taken five years and Baumgartner successfully completed a test jump from 18 miles up in July. The current record holder for the highest jump, Joe Kittinger, 84, will be with Baumgartner's control team on the ground. Kittinger's record has stood since 1960 when, as a young US Air Force captain, he leapt from 19.5 miles and survived.
Baumgartner has said he "does not have a death wish" and hates being called an "adrenalin junkie". He describes himself as simply "a person who likes a challenge". If the jump is successful, he intends to retire from stunts and become a helicopter mountain rescue pilot. Nasa is taking a keen interest in the stunt to assess the impact of supersonic free fall on the human body.