Gusty winds at Roswell, New Mexico, have prevented the launch of the helium balloon that was to take him to more than 120,000ft (36.5km). His meteorologist has now ruled out a Thursday jump, and the team will hold a briefing to talk about next steps.
Baumgartner is trying to topple records that have stood for more than 50 years. The previous highest skydive was made by retired US Air Force Col Joe Kittinger, who leapt from a helium envelope in 1960. His altitude was 102,800ft (31.3km). What he is trying to do is extremely dangerous.
At an altitude of 120,000ft (36.5km), the air pressure is less than 2% of what it is at sea level, and it is impossible to breathe without an oxygen supply. Others who have tried to break the records for the highest, fastest and longest freefalls have lost their lives in the process.