Branson, 46, Per Lindstrand and Rory McCarthy were told yesterday morning that ground conditions in Morocco were suitable for the launch. The Virgin boss interrupted a holiday in Klosters to go to North Africa. The trio are likely to make their attempt from a military base in Marrakesh tomorrow or on Wednesday.
Last year's attempt was aborted because of bad weather in Morocco.
This week's effort is being dedicated to the memory of Matthew Harding, the vice-chairman of Chelsea Football Club, who died last year in a helicopter crash returning from a match.
His company, the Benfield Group, is patron of the record-breaking attempt.The balloon's planned flight path will take it from Morocco over Algeria, Egypt, India, Bangladesh, the South China Sea, Japan, the USA and back to Britain.
Branson and his fellow fliers will encounter varying climates during their proposed 18-day flight, ranging from the heat of North Africa to the harsh winds and bitter chill of the Atlantic Ocean.
Branson almost came to grief when his catamaran Virgin Atlantic Challenger was holed and wrecked in August 1985 as he attempted to cross the Atlantic in record time.
He and the rest of the crew abandoned the vessel in liferafts and were flown to safety. However, next year he captured the Blue Riband title for the fastest Atlantic crossing when his powerboat Virgin Atlantic Challenger II made the trip in three days, eight hours and 31 minutes. It cut two hours and nine minutes off the record set 34 years previously by the American liner the United States.
In 1987 Branson promised to give up dangerous exploits after the near- fatal end to his first ballooning adventure.
In the Irish Sea, after completing the first transatlantic crossing, the co-pilot, Lindstrand, jumped into the water when the balloon looked certain to crash.
The damaged craft then shot skywards, with Branson waving red underpants to attract the attention of a naval helicopter.