March 15, 2012 Balloon capacity: 1.22 million cubic feet Balloon height at launch: 357 feet July 25, 2012 Balloon capacity: 5.3 million cubic feet Balloon height at launch: 476 feet October 14, 2012 Balloon capacity: 29.47 million cubic feet Height at launch: 739 feet The 29.47 mcf balloon was made from 40 acres of polyethylene, and, including the flight train, at launch it would be twice as tall as a Saturn 5 rocket. To launch with maximum safety, winds needed to be no more than 2 mph from ground level up to 800 feet AGL. Typically, large balloon launches occur at dawn, when winds are most calm. On October 14, ground conditions were indeed calm at sunrise, but a strong temperature inversion caused increased winds beginning at 685 feet AGL, with winds of 25 mph at 800 feet AGL. Those high-level winds wouldn’t have impacted the smaller balloons used for Baumgartner’s first two test ascents, but they were a major concern for the integrity of the large balloon needed to take him to over 120,000 feet in the final mission. “If we had released the balloon, it would have been a very dangerous situation for Felix,” Day stated. Day, Coca and the team waited for the inversion to dissipate, which typically occurs relatively early in the morning, post sunrise. However, once an inversion burns off, it’s seldom long before thermals build up. Thus Day predicted that the team would have a window of only 15 minutes to safety launch the balloon. The team would need to work in perfect synchronicity: Day likened it to “a football play where everybody blocks exactly the right man and the result is a touchdown.” The “touchdown” for the team occurred at 9:28 a.m. Mountain Time, as the balloon launched successfully from the flightline.
Red Bull Stratos Scientific Summit
60