With the launch date for the record-breaking freefall edging ever closer, we’ve taken a closer look at the vital piece of kit that will take Felix Baumgartner and his capsule to the edge of space – namely the helium balloon…
When Felix Baumgartner and the Red Bull Stratos team first started to investigate the possibility of travelling 36,576 metres (120,000 feet) into the stratosphere to make the world’s highest ever supersonic freefall attempt, they knew they had to find just the right mode of transportation to get them there.
In the end, only the best would do for our brave adventurer, so a helium-filled balloon was decided upon. But not just any old helium balloon.
Non-flammable and non-toxic, the balloon is constructed of strips of high-performance polyethylene film measuring a surprisingly thin 0.0008 inches and with a capacity of 30 million cubic feet – that’s 10 times larger than Joe Kittinger’s record-setting balloon in 1960.
Fully inflated, the balloon with measure 55 storeys high and will require two large truckloads of helium to get it launch ready.
Once up, up and away, the balloon will ascend at about 1,000 meters per minute. Upon reaching about 100,000 feet, however, it will likely slow to roughly 750 feet per minute until it levels off at approximately 120,000 feet above sea level – Felix’s intended stopping point.
This height is known as Float Altitude and it’s determined in a very scientific way. You see, helium is lighter than air, but as the balloon rises ever higher the air density is reduced and therefore so is the rate of climb. Float altitude is reached when the average density of the balloon is the same as the density of the surrounding atmosphere – ergo, not too far into space!
At the point at which the balloon naturally stops, Felix will commence his final jump preparations and hopefully launch himself into the history books.
Once Felix has safely landed, Mission Control will trigger the separation of the capsule and balloon, so that the capsule can descend under its parachute. A nylon ‘destruct line’ will release the helium so that the balloon also safely returns to Earth.
It’s a method that has been refined over the past 60 years and great leaps forward have been made since the inception of the Red Bull Stratos mission. As Technical Project Director Art Thompson says: “They’re very expensive, they’re very hard to get and it’s very difficult to talk people into even selling you balloons of this type.”
To find out more about the helium balloon and Red Bull Stratos project, check out the video below…
By Red Bull
Source: Red Bull