The men were only saved from death by Alex Ritchie, 52, who clambered in the dark onto the capsule roof and detached two one-ton propane tanks to lighten the 11-ton balloon and halt the descent. At that stage they were so close to the ground they would have been killed even if they had jumped out.
Mr Branson denied that the crash in the Algerian desert meant the attempt to fly around the world non-stop had been a failure. "It's not that important what we are trying to do," he said. "What matters in the end is that we're still alive. We find these challenges irresistible, but it's great to be home."
He again said that he would have to think carefully before trying the exploit again. Per Lindstrand, a teammate and the balloon's designer, commented: "Each time I have flown with Richard, he has landed and sworn he will never do it again - then changed his mind."
They blamed the crash on a fundamental design flaw in the huge balloon which meant it could not keep flying as the temperature fell at night.
Mr Branson said: "As it got dark, the balloon started going down, we turned the burners up to try to heat the helium to stop the descent. That didn't work, the balloon continued to fall. We picked up speed, and at 10,000 feet we ballasted, and were rapidly getting through most of the ballast that we carried on board. We then started chucking out water, food and oil ... And we found that we continued to go down. At that rate we were seven minutes from hitting the ground, descending at 2,000 feet a minute."
Mr Ritchie struck a modest note, saying: "Maybe it was just as well it was dark, I couldn't see the ground. If I had been able to see how fast the ground was approaching, I might have fumbled things."
Mr Lindstrand said that the balloon's sensitivity to the temperature change as the sun fell was "quite dramatic". The lifting canopy, with a capacity of 1.1 million cubic feet, consisted of helium gas around a small hot-air balloon, intended to heat up the helium to provide lift. Although earlier tests by Mr Lindstrand on smaller designs were successful, the full-scale version had never been tested before this week's flight. As the team learnt, the small balloon could not heat the helium enough as the outside temperature fell below freezing
Mr Branson said "We know that fundamentally the whole concept works. The difficulty of heating the helium at night-time is the only thing that really needs to be overcome to make this work."Reuse content