0:00:04 > 0:00:07On Sunday 14th of October 2012...
0:00:07 > 0:00:11'Mission Control. Perfect conditions for launch.'
0:00:11 > 0:00:14..the world watched as Felix Baumgartner
0:00:14 > 0:00:20climbed aboard a space capsule and flew a balloon 39km above the Earth.
0:00:20 > 0:00:23'We are away, Felix is away.'
0:00:23 > 0:00:27At 128,000ft, he left the capsule,
0:00:27 > 0:00:30stood on a tiny step...
0:00:32 > 0:00:34..and jumped.
0:00:37 > 0:00:40He became the first person
0:00:40 > 0:00:43to freefall faster than the speed of sound.
0:00:45 > 0:00:48This incredible achievement took skill,
0:00:48 > 0:00:51bravery and cutting edge science.
0:00:52 > 0:00:55It took a team of engineers
0:00:55 > 0:00:59and doctors four years to prepare Felix for the task.
0:00:59 > 0:01:05Sometimes feels like...I can't do it, it's just too much.
0:01:05 > 0:01:09They had to build the biggest balloon ever made for manned
0:01:09 > 0:01:13flight and battle the weather just to get it off the ground.
0:01:15 > 0:01:20They had to engineer a pressurised capsule to protect
0:01:20 > 0:01:25Felix from the deadly environment at 128,000ft.
0:01:25 > 0:01:29I call this a plumbing diagram. We're space plumbers!
0:01:31 > 0:01:35Felix had to survive in a place where low pressure
0:01:35 > 0:01:38and lack of oxygen could kill him in an instant.
0:01:42 > 0:01:46They had to design next generation pressure suit that Felix
0:01:46 > 0:01:49could skydive in.
0:01:49 > 0:01:51It's a piece of art.
0:01:51 > 0:01:54They had to study flight aerodynamics
0:01:54 > 0:01:57and overcome the dangers of a supersonic spin.
0:01:59 > 0:02:02He's spinning, isn't he?
0:02:02 > 0:02:06But Felix had to break a record that was set over 50 years ago,
0:02:06 > 0:02:10by this man, Colonel Joe Kittinger.
0:02:20 > 0:02:26In 1960, nine years before man first stepped on the moon, Joe took
0:02:26 > 0:02:31one of the first journeys to the very edge of the Earth's atmosphere.
0:02:35 > 0:02:39His mission was to lay the foundations for space travel.
0:02:41 > 0:02:46And to see if a pilot could survive a bailout at extreme altitude.
0:02:49 > 0:02:55At just over 100,000ft, Joe leapt from his balloon.
0:02:55 > 0:02:56I took a deep breath...
0:02:59 > 0:03:01I said, "Lord, take care of me now."
0:03:10 > 0:03:14The data from his jump helped develop a parachute escape system
0:03:14 > 0:03:18still used by high altitude pilots today.
0:03:20 > 0:03:26Joe came out of retirement to help Felix break his own record.
0:03:26 > 0:03:30Together, they pushed the boundaries of science to get Felix
0:03:30 > 0:03:35safely through the sound barrier and into the record books.
0:03:35 > 0:03:39Felix, we're so proud of you. You did absolutely fabulous!
0:03:39 > 0:03:43Absolutely fabulous! I couldn't have done any better myself.
0:03:59 > 0:04:03Felix Baumgartner's mission depends entirely on one of the least
0:04:03 > 0:04:07heralded but most remarkable pieces of equipment - a balloon.
0:04:07 > 0:04:11It's the oldest flying machine of them all.
0:04:11 > 0:04:15People have been flying balloons for over 200 years.
0:04:15 > 0:04:18But this one sets a new standard.
0:04:20 > 0:04:23It's the biggest ever designed for a manned flight
0:04:23 > 0:04:27and it means Felix will enter the record books even before he jumps.
0:04:28 > 0:04:33So Felix is going to set another record that we really don't
0:04:33 > 0:04:38think about, which is the largest manned balloon ever flown.
0:04:38 > 0:04:43The balloon built for Felix will hold 30 million cubic feet of gas.
0:04:45 > 0:04:47Although it's incredibly thin,
0:04:47 > 0:04:53it's designed to carry a capsule the weight of a car 39km up.
0:04:54 > 0:04:57It will be filled with helium
0:04:57 > 0:05:00until it's as tall as a 50 storey building.
0:05:00 > 0:05:06It's amazing that this piece of plastic that is no thicker
0:05:06 > 0:05:11than a dry cleaner bag that's going to hold up all this weight.
0:05:12 > 0:05:17There's a series of nylon strings that run through that balloon
0:05:17 > 0:05:20material to be able to carry the weight.
0:05:20 > 0:05:24As the balloon climbs, the helium expands
0:05:24 > 0:05:28until it is the width of a football field.
0:05:28 > 0:05:32On launch, the balloon is teardrop shaped, but as it goes up
0:05:32 > 0:05:37into the atmosphere, you're going into a near vacuum, that gas bubble
0:05:37 > 0:05:43is expanding, so now the balloon ends up in almost a circular size.
0:05:48 > 0:05:51When the atmosphere outside the balloon thins to the point
0:05:51 > 0:05:56where its density equals that of the gas inside the balloon,
0:05:56 > 0:05:59it can no longer climb.
0:05:59 > 0:06:03Felix will have reached the end of his epic balloon journey.
0:06:06 > 0:06:08At least, that's the theory.
0:06:08 > 0:06:13The problem is the balloon is very difficult to launch.
0:06:13 > 0:06:17The team sends up weather balloons called pie-balls to measure
0:06:17 > 0:06:19wind speeds.
0:06:19 > 0:06:24Felix's balloon is so big it needs near perfect calm to inflate.
0:06:24 > 0:06:28Not just at ground level, but all the way up its height.
0:06:28 > 0:06:32Only when the pie-balls are perfectly aligned is it safe
0:06:32 > 0:06:34to begin the launch.
0:06:39 > 0:06:45But on the team's first attempt, wind speeds changed suddenly,
0:06:49 > 0:06:51with disastrous results.
0:06:58 > 0:07:02Felix, The winds came up.
0:07:02 > 0:07:05- We'll have to abort.- No way.
0:07:14 > 0:07:18The team had to wait for a second chance a few days later.
0:07:20 > 0:07:25They used their reserve balloon and this time, conditions were perfect.
0:07:25 > 0:07:27The launch was successful.
0:07:31 > 0:07:35CHEERING
0:07:36 > 0:07:42Felix set a new record for the highest ever manned balloon flight.
0:07:42 > 0:07:45'Felix, you're on the way to space.'
0:07:49 > 0:07:51'You're going up just great.'
0:08:01 > 0:08:06Felix Baumgartner is making a journey to the edge of space.
0:08:06 > 0:08:10His survival will rely on two crucial pieces of equipment -
0:08:10 > 0:08:14his pressure suit and space capsule.
0:08:14 > 0:08:18Each poses significant technical challenges.
0:08:18 > 0:08:21The pressure suit is Felix's life support system as he ventures
0:08:21 > 0:08:24to the very edge of the atmosphere.
0:08:24 > 0:08:28To do its job, the suit needs to be rigid and strong.
0:08:28 > 0:08:33Unfortunately, that makes it very difficult to skydive in.
0:08:34 > 0:08:38So Felix has to undergo special training.
0:08:39 > 0:08:43There are very few people that have jumped in pressure suits.
0:08:43 > 0:08:48Of those four people who did that, two died.
0:08:48 > 0:08:51And two lived.
0:08:51 > 0:08:54Retired colonel Joe Kittinger was the first man to ever
0:08:54 > 0:08:59jump in a pressure suit and Felix's suit is being made in the same
0:08:59 > 0:09:03factory where Joe's was over 50 years ago.
0:09:04 > 0:09:09You appreciate the suit a lot more if you see how it has been built.
0:09:09 > 0:09:13Next time when I step into my suit, I'm going to take my time, you know?
0:09:14 > 0:09:17Felix's pressure suit has been specially designed to give
0:09:17 > 0:09:21more flexibility while still giving as much protection as a full
0:09:21 > 0:09:23space suit.
0:09:23 > 0:09:26It will keep him warm, safely pressurised
0:09:26 > 0:09:28and supplied with oxygen.
0:09:30 > 0:09:33There's actually four layers to this suit.
0:09:33 > 0:09:37The outer cover that you see here is made out of Nomex,
0:09:37 > 0:09:41which is a fire retardant material. The inner portion of the suit,
0:09:41 > 0:09:46one of the things that we have is something we call link netting
0:09:46 > 0:09:51and what link netting does is it retains the torsal shape of the body.
0:09:51 > 0:09:55Inside the link netting, we actually have the bladder material.
0:09:55 > 0:09:57Which is made out of Gore-Tex,
0:09:57 > 0:10:00which actually vents the moisture out of the inside of the suit to
0:10:00 > 0:10:04the atmosphere, but it maintains pressure.
0:10:04 > 0:10:08The clever design and materials make Felix's suit a little easier
0:10:08 > 0:10:12to skydive in than a traditional pressure suit.
0:10:12 > 0:10:15But it's still highly restrictive.
0:10:15 > 0:10:19Felix is used to skydiving in clothes that offer virtually
0:10:19 > 0:10:21no restrictions on his movement,
0:10:21 > 0:10:25so he needs to get used to freefalling in the pressure suit.
0:10:25 > 0:10:29He begins training by jumping from 15,000ft.
0:10:33 > 0:10:36On one jump, things go terribly wrong.
0:10:41 > 0:10:44Felix has accidentally pulled the wrong cord,
0:10:44 > 0:10:46cutting away his main parachute.
0:10:46 > 0:10:49That's his parachute.
0:10:49 > 0:10:51And now he can't find his reserve.
0:10:54 > 0:10:59Just moments before it's too late, he finds it.
0:10:59 > 0:11:02- We've got to go get him. - We've got to go get him.
0:11:02 > 0:11:05The restrictions of the suit caused him
0:11:05 > 0:11:08to confuse his parachute handles.
0:11:08 > 0:11:12The team are forced to redesign Felix's parachute rig to make
0:11:12 > 0:11:16it easier for him to use with the suit.
0:11:16 > 0:11:18I'm still alive!
0:11:22 > 0:11:25Because the space suit is so restrictive,
0:11:25 > 0:11:29the team don't want to inflate till they have to.
0:11:29 > 0:11:34So Felix will travel to his jump height in a pressurised capsule,
0:11:34 > 0:11:37only inflating the suit when he's about to jump.
0:11:37 > 0:11:41Because the capsule will be travelling to the edge of space,
0:11:41 > 0:11:45it has to be built to withstand low pressure and extreme cold.
0:11:47 > 0:11:51The pressure capsule, the space capsule, what it does is
0:11:51 > 0:11:55the atmosphere is held at 16,000ft,
0:11:55 > 0:11:58so now his entire flight
0:11:58 > 0:12:03throughout the three hour process is just as if he's flying at 16,000ft.
0:12:03 > 0:12:07It's very low exposure and his suit now is not inflated,
0:12:07 > 0:12:10so he has high mobility.
0:12:10 > 0:12:13The team have chosen materials that expand and contract at similar
0:12:13 > 0:12:18rates, so that the capsule remains pressure tight all the way up.
0:12:19 > 0:12:25The pressure suit itself is a composite epoxy fibreglass.
0:12:26 > 0:12:29The acrylic door, it's a 4ft diameter acrylic door,
0:12:29 > 0:12:32it's half an inch thick.
0:12:32 > 0:12:37Most materials will reduce in size because of the cold temperatures.
0:12:37 > 0:12:41The fibreglass contracts at about the same rate as the acrylic,
0:12:41 > 0:12:47so it's important to use fibreglass epoxy on the pressure suit.
0:12:47 > 0:12:50Thanks to his pressurised capsule, Felix only had to rely
0:12:50 > 0:12:54on his suit from the moment when the acrylic door swung
0:12:54 > 0:12:59open and his body was exposed to the near vacuum of space.
0:13:07 > 0:13:10Felix Baumgartner is attempting to break
0:13:10 > 0:13:14the record for the longest, furthest and fastest freefall.
0:13:14 > 0:13:16But before he even jumps,
0:13:16 > 0:13:21he will have to survive a trip through a death zone, an environment
0:13:21 > 0:13:26so inhospitable that it's impossible for any human to survive unaided.
0:13:31 > 0:13:34Felix isn't the first person to attempt to break the skydive
0:13:34 > 0:13:39record set by test pilot Joe Kittinger over 50 years ago.
0:13:39 > 0:13:44Not long after Joe set the record, another man tried to break it.
0:13:44 > 0:13:49But he wasn't as prepared for the hazards of high altitude flight.
0:13:53 > 0:13:57Nick Piantanida was a 35-year-old skydiver who had
0:13:57 > 0:14:00dreams of beating Joe's record.
0:14:00 > 0:14:06Like Felix, Nick had no experience of working at extreme altitude.
0:14:06 > 0:14:10Life support engineer Mike Todd, who is responsible for the equipment
0:14:10 > 0:14:15that will help keep Felix alive, was also involved in Nick's attempt.
0:14:15 > 0:14:21Nick was going at 125,000ft. We were supplying him with a parachute.
0:14:21 > 0:14:26We didn't quite have the backing that was have on this project.
0:14:26 > 0:14:31On the 1st of May 1966, Nick took off in his gondola.
0:14:31 > 0:14:36A recording of his communication with Mission Control has survived.
0:14:53 > 0:14:58Midway through his journey, something went terribly wrong.
0:15:04 > 0:15:07He was probably up around 50,000 feet.
0:15:07 > 0:15:09Some way or other, the visor was opened,
0:15:09 > 0:15:12either accidentally or intentionally.
0:15:13 > 0:15:15We really don't know.
0:15:15 > 0:15:18The people on the ground immediately cut the balloon
0:15:18 > 0:15:22away from the gondola, by the time they got to him they found him
0:15:22 > 0:15:26outside of the gondola, with the visor partially open.
0:15:26 > 0:15:30Nick was in a coma, caused by a condition known as hypoxia.
0:15:31 > 0:15:33He died four months later.
0:15:35 > 0:15:37We're talking about the medical
0:15:37 > 0:15:41and physiological considerations of an extreme altitude jump.
0:15:42 > 0:15:46Felix's medical team want him to understand the risks of hypoxia
0:15:46 > 0:15:51and the other life-threatening conditions he will face at altitude.
0:15:52 > 0:15:57The definition of hypoxia, it's a deficiency of oxygen.
0:15:57 > 0:15:58These are the symptoms.
0:15:59 > 0:16:04You may get impaired deficiency, drowsiness, poor judgement,
0:16:04 > 0:16:09visual blurring, extreme fatigue, you're not really functional,
0:16:09 > 0:16:11at that point.
0:16:11 > 0:16:15The lack of oxygen in the thin atmosphere at high altitude
0:16:15 > 0:16:17means Felix is at risk of hypoxia.
0:16:19 > 0:16:22He will need to breathe from a canister throughout his mission.
0:16:22 > 0:16:26If this equipment failed above 45,000 feet,
0:16:26 > 0:16:30he would fall unconscious in under 15 seconds.
0:16:30 > 0:16:35If something goes wrong, you're all by yourself. That is really scary.
0:16:35 > 0:16:39This is what I'm thinking about all the time.
0:16:39 > 0:16:42There is another danger Felix has to prepare for.
0:16:42 > 0:16:46It is called decompression sickness, or the bends -
0:16:46 > 0:16:50a condition also faced by divers.
0:16:50 > 0:16:53Air contains both nitrogen and oxygen,
0:16:53 > 0:16:57but nitrogen expands faster as pressure falls.
0:16:57 > 0:17:01When a person travels quickly from a relatively high-pressure environment
0:17:01 > 0:17:04to a relatively low-pressure environment,
0:17:04 > 0:17:07the result can be fatal.
0:17:08 > 0:17:12When you look at the bends as an example, when you're diving,
0:17:12 > 0:17:17if you go down into the bottom of the pool, you blow a bubble,
0:17:17 > 0:17:20that bubble is this big when you blow the bubble out,
0:17:20 > 0:17:24by the time it reaches the top, it's this big.
0:17:24 > 0:17:29So the nitrogen that's trapped in solution in your body, in your blood,
0:17:29 > 0:17:33if you go up too quickly, that gas bubble is going to expand,
0:17:33 > 0:17:39it is in your veins, in your tongue, in your head.
0:17:39 > 0:17:40You get the bends.
0:17:48 > 0:17:52Felix wears a space suit to protect against decompression sickness.
0:17:53 > 0:17:56But he also takes one final precaution to reduce the risk
0:17:56 > 0:18:00of nitrogen bubbling out of his blood at altitude.
0:18:01 > 0:18:05For one hour before his flight, he breathes pure oxygen.
0:18:07 > 0:18:12Oxygen pre-breathe is really important for this mission
0:18:12 > 0:18:15because it washes out nitrogen.
0:18:15 > 0:18:18So you breathe oxygen, wash out nitrogen,
0:18:18 > 0:18:20and reduce the chance of decompression sickness.
0:18:21 > 0:18:25But pre-breathing cannot protect Felix against the final
0:18:25 > 0:18:30and most terrifying danger he faces on his balloon trip
0:18:30 > 0:18:35to the edge of space - as Felix rises above 63,000 feet,
0:18:35 > 0:18:39he passes through what is called the Armstrong Line.
0:18:39 > 0:18:43Above this point, atmospheric pressure becomes so low,
0:18:43 > 0:18:47all the gases in his body will try to escape.
0:18:47 > 0:18:50It is a condition called ebullism.
0:18:50 > 0:18:54The gas is trying to find the fastest path out of your body.
0:18:56 > 0:19:00You will start to ooze from your eyes, start frothing at the mouth,
0:19:00 > 0:19:03out of every orifice you have, you will start to ooze.
0:19:03 > 0:19:06It's like the worst possible horror film.
0:19:11 > 0:19:14On the day of Felix's record-breaking jump,
0:19:14 > 0:19:18his pressure suit and oxygen supply worked perfectly.
0:19:19 > 0:19:23All of the team's precautions and hard work paid off.
0:19:24 > 0:19:30Felix got safely up to 128,000 feet.
0:19:40 > 0:19:46Felix Baumgartner is attempting to freefall from 128,000 feet,
0:19:46 > 0:19:49five times higher than the maximum altitude normally
0:19:49 > 0:19:53attempted by skydivers jumping from a plane.
0:19:53 > 0:19:56His team have to anticipate the extra risks
0:19:56 > 0:19:59of falling from such an extreme height.
0:19:59 > 0:20:02Their biggest fear is that, as Felix falls,
0:20:02 > 0:20:07he could go into what is known as a flat spin.
0:20:08 > 0:20:11What causes the flat spin is an odd position in freefall.
0:20:11 > 0:20:14You have one extremity sticking out more than the other.
0:20:14 > 0:20:17The faster you go, the more drag affects what you do.
0:20:17 > 0:20:19If I have one arm off a little more than the other arm,
0:20:19 > 0:20:22and I don't notice it, it could cause me to spin.
0:20:22 > 0:20:28Felix is jumping into a near vacuum at the edge of the earth's atmosphere.
0:20:28 > 0:20:32This means any changes in his body position could spell disaster.
0:20:35 > 0:20:39Flat spin is a really serious concern.
0:20:39 > 0:20:43In a vacuum, there is very little to stop motion.
0:20:44 > 0:20:50The fear is that if Felix starts spinning at any kind of rate,
0:20:50 > 0:20:53it could get to the point where he would not be able to control.
0:20:53 > 0:20:57This is what happened to Felix's mentor, Joe Kittinger,
0:20:57 > 0:21:01on one of his jumps over 50 years ago.
0:21:01 > 0:21:06When I was freefalling, all of a sudden I had this violent rotation.
0:21:08 > 0:21:12It was so violent I could not pull my arms in.
0:21:12 > 0:21:16I couldn't do anything, I was just...paralysed.
0:21:18 > 0:21:21Joe's camera captured just how violent this spin was.
0:21:23 > 0:21:27I spun up 120 rpm, I was unconscious, I could have died.
0:21:29 > 0:21:33There are two types of flat spin, both can be deadly.
0:21:34 > 0:21:37If Felix spins with his head in the centre,
0:21:37 > 0:21:41the G-force will pull the blood out of his brain, causing a blackout.
0:21:42 > 0:21:44If his feet are at the centre,
0:21:44 > 0:21:47then the blood will rush into his brain, causing what is
0:21:47 > 0:21:52known as a red out, which could cause an aneurysm or brain damage.
0:21:57 > 0:22:02Joe only survived his spin because his parachute fired automatically.
0:22:02 > 0:22:05But Felix will be freefalling too fast for any
0:22:05 > 0:22:08normal automatic parachute.
0:22:11 > 0:22:14So his team throw themselves at the problem.
0:22:14 > 0:22:17How do you stop a supersonic flat spin?
0:22:21 > 0:22:24How much of a spin is too much for you to recover from?
0:22:24 > 0:22:25Nobody really knows.
0:22:29 > 0:22:31Was that fast enough that time?
0:22:31 > 0:22:33When I'm spinning so fast that I can't bring my arms in,
0:22:33 > 0:22:35that's too much of a spin.
0:22:35 > 0:22:36That's my first take on it.
0:22:36 > 0:22:38But I didn't know how much that was,
0:22:38 > 0:22:41so I went skydiving and I tried different things,
0:22:41 > 0:22:46and I took a G-meter up to see how much I spun, and what the effect was.
0:22:47 > 0:22:49Luke tests lots of systems
0:22:49 > 0:22:53but cannot find one that will cope with the G-force Felix will achieve.
0:22:55 > 0:22:56Then he has a brainwave.
0:23:00 > 0:23:05To borrow a technology used by the military to guide supersonic bombs.
0:23:05 > 0:23:08It is called a drogue parachute.
0:23:08 > 0:23:12We have a specially-designed drogue that can handle supersonic speeds.
0:23:12 > 0:23:14We have attached at his shoulders rather
0:23:14 > 0:23:18than in the middle of his back like a normal skydiver.
0:23:18 > 0:23:21So I'm out of control, fire the drogue,
0:23:21 > 0:23:23it grabs you and flips you the right side up.
0:23:25 > 0:23:28Pretty amazing how well that works.
0:23:28 > 0:23:31But there's still a problem.
0:23:31 > 0:23:35If Felix is spinning so fast he cannot move his arms,
0:23:35 > 0:23:36how can he pull the drogue?
0:23:38 > 0:23:40Now I'm going to spin this thing around.
0:23:40 > 0:23:45If he's spinning about this fast for six seconds,
0:23:45 > 0:23:49we came up with a device that will automatically fire the drogue.
0:23:49 > 0:23:52You will see the light come on and the drogue fires.
0:23:59 > 0:24:03In Felix's record-breaking jump, he did go into a spin.
0:24:03 > 0:24:05He's spinning, isn't he?
0:24:05 > 0:24:08But he didn't spin long enough for his drogue to fire.
0:24:09 > 0:24:13He managed to regain control and land safely.
0:24:13 > 0:24:17APPLAUSE AND CHEERING
0:24:30 > 0:24:35For Felix to skydive from higher than anyone has ever dared,
0:24:35 > 0:24:39he must also do something no human has ever done -
0:24:41 > 0:24:44freefall through the sound barrier.
0:24:44 > 0:24:49In a computer animation, it looks straightforward enough,
0:24:49 > 0:24:53but the reality is nobody knows if this is even possible.
0:24:54 > 0:24:59We are putting Felix into a condition that really has never been done,
0:24:59 > 0:25:01and has never been documented for sure.
0:25:03 > 0:25:07So we don't know what happens to the body at the speed of sound.
0:25:09 > 0:25:12Felix practices freefalling at an angle that gives him
0:25:12 > 0:25:15the best chance of going supersonic quickly and safely.
0:25:17 > 0:25:20It is called the Delta position.
0:25:20 > 0:25:24Arms back, tilted forward, head down.
0:25:25 > 0:25:26But first,
0:25:26 > 0:25:30he'll have to break through what is known as the transonic wall.
0:25:30 > 0:25:34This is the moment when some parts of Felix's body begin to go supersonic
0:25:34 > 0:25:37while other parts are still subsonic.
0:25:38 > 0:25:43These tiny differences in speed could cause violent vibrations.
0:25:45 > 0:25:47What occurs is a pressure wave,
0:25:47 > 0:25:51if you can imagine an air molecule suspended in the air,
0:25:51 > 0:25:55and as this object is coming by, trying to reach the speed
0:25:55 > 0:25:59of sound, these air molecules are crashing into each other,
0:25:59 > 0:26:03they have to get out of the way, so it creates this pressure wave.
0:26:03 > 0:26:05And as it goes out of the transonic phase,
0:26:05 > 0:26:10you will find different areas going into supersonic at different times.
0:26:10 > 0:26:15These different wave patterns create a convergence where the wave
0:26:15 > 0:26:18shocks against each other, causing a buffeting.
0:26:18 > 0:26:23In early supersonic jets, this caused extreme vibrations.
0:26:23 > 0:26:28In Felix, these could damage his organs, and even kill him.
0:26:31 > 0:26:34But none of these risks were enough to stop him
0:26:34 > 0:26:38from making his record-breaking jump.
0:26:45 > 0:26:49On October 14th 2012,
0:26:49 > 0:26:54Felix Baumgartner became the fastest skydiver in history.
0:26:59 > 0:27:02He went faster than a jumbo jet after 25 seconds.
0:27:04 > 0:27:07Moments later, faster than a .45 calibre bullet.
0:27:10 > 0:27:14After 35 seconds, he broke the sound barrier.
0:27:19 > 0:27:22The speed of sound is affected by altitude and temperature.
0:27:23 > 0:27:27Felix fell at temperatures of -45 degrees centigrade.
0:27:29 > 0:27:31The cold air and the low pressure enabled him
0:27:31 > 0:27:35to go supersonic at around 690 mph -
0:27:37 > 0:27:41some 10 mph less than a normal air pressure at ground level.
0:27:44 > 0:27:48As Felix fell back to Earth, the dense air in the
0:27:48 > 0:27:52lower atmosphere acted as a drag on his body, slowing him down.
0:27:54 > 0:27:58Felix's speed fell from supersonic to subsonic,
0:27:58 > 0:28:03eventually reaching his maximum terminal velocity.
0:28:03 > 0:28:06This meant he could no longer continue accelerating.
0:28:13 > 0:28:15I'm feeling quite nauseous.
0:28:21 > 0:28:23Yes!
0:28:50 > 0:28:54Subtitles by Red Bee Media Ltd