The balloon team, sponsored by British communications group Cable and Wireless Plc, was headed southwest towards the Canary Islands to catch a subtropical jet stream. They hope the jet stream will carry them over Morocco, Algeria, Libya, and Egypt on the first leg of a journey that could last up to three weeks.
Pilots Andy Elson, 45, and Colin Prescot, 48, are both experienced balloonists and have set several previous records.
"It looked fantastic," said Prescot's wife, Susie. "It's exactly as Andy and Colin intended it to be."
Cable and Wireless balloon team engineers worked all night to inflate the giant balloon, which carries an enclosed capsule to protect the pilots from freezing cold while cruising around 33,000 ft.
About 200 cheering spectators were on hand for lift-off, which was delayed for several hours to take advantage of more favorable winds.
Some 20 earlier attempts to circle the globe have failed, the most recent by British tycoon Richard Branson and American Steve Fosset, who came down in the Pacific on December 25.
Flying at an average speed of 80 miles per hour, the balloon was to pass over North Africa, India, and Hong Kong before crossing the Pacific and entering the United States.
The team was to then pass over the Atlantic in an effort to touch down somewhere in the Mediterranean region. Eighty solar panels provide power for the balloon's batteries.
Elson and Prescot's round-the-world attempt is one of at least six now being prepared. Other teams also hope to take advantage of the November-to-February season when high-level jet stream winds are at their best.
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