# Skydiver Baumgartner in 128,000ft plunge from brink of space

Skydiver Felix Baumgartner jumped 128,000 feet (24 miles, 39km) out of a balloon today, to complete the highest skydive in history. It took just under 10 minutes for the Austrian to reach the desert surface below. The Red Bull Stratos space capsule finally got off the ground at Roswell, New Mexico, following two aborts on the …

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#### Cool!

This is excellent. I wish him every success.

Vic.

#### Re: Cool!

Yes Congrats all around. Wow still check out the story the author alludes to with the SR71 in the 1960's. Amazing stuff was going on in the AF and with NASA at this time and its cool to see even a small piece recreated today. Amazing story of survival.

#### Re: Cool!

Watching it live. Now if they could do something about the annoying announcer... Still very cool.

Well one of the guys talking was the previous record holder for this sort of thing and Felix only wanted to hear him on the radio.

#### Sound barrier?

The daredevil will break the sound barrier at 1,110 km/h (690mph) during his descent

This is the speed of sound at 0C. It varies with temperature and therefore altitude:

en.wikipedia.org/wiki/Speed_of_sound

#Altitude_variation_and_implications_for_atmospheric_acoustics

So by "sound barrier" do you mean journalese sloppiness like "the FT index broke the 6000 barrier" or do you actually mean that he will encounter the aeronautic effects of passing through the air that surrounds him faster than sound does?

#### Re: Sound barrier?

There is a table of the speed of sound at various altitudes here http://www.aerospaceweb.org/question/atmosphere/q0112.shtml

That table suggest that the if they are expecting to break the speed of sound while it's 690 mph they will have to do it in the first few thousand feet and that he really will be passing through the air surrounding him faster than sound.

There is something not quite right though. In rough numbers 690 mph is 300 m/s. It has to take him a minimum of 30 seconds to get to that speed by which time he has fallen 0.5 * 10 * 30^2 = 4500m = 13,500 ft. Add a bit for drag and my rounding and he'll be breaking the local sound barrier at 100,000ft or so, where it's only 675 mph.

I suspect the difference comes down to the difference between the actual atmosphere on the day he's jumping and the simplified model used by aerospaceweb.org

#### Re: Sound barrier?

> the simplified model used by aerospaceweb.org

I suspect the aerodynamic calculations are somewhat complicated by the effect of the large spherical objects between his legs...

Vic.

#### Re: Sound barrier?

For anyone keeping track, he thoroughly smashed the sound barrier, clocking in a peak mach number (factoring in altitude, approximate temperature etc.) of mach 1.24, at some 373m/s. That's faster than the speed of sound even at sea level.

#### the FT index broke the 6000 "barrier"

This is no criticism of the OP but the analogy is inappropriate.

Having working in finance for 20+ years I can safely say that psychological support/resistance levels/barriers are confined to the realms of the imagination and the financial press. They are not taken seriously by practitioners in the financial markets and those who speak of them show their lack of understanding about financial markets work.

#### Re: the FT index broke the 6000 "barrier"

The reason for asking this question was that I thought that the speed of sound would vary a lot with height. However, the table that Chris 48 helpfully linked shows that it is greatest (340m/s) at ground level, decreases or increases with height in the various layers of the atmosphere and is least (274m/s) at 90km.

psychological support/resistance levels/barriers are confined to the realms of the imagination and the financial press

That's exactly what I meant. Numbers ending in 000 are not barriers.

Equally, the speed of sound at ground level is not relevant to someone a long way up.

However, we have established that he broke the sound barrier, even though it is not clear at what altitude or speed this was. It will be interesting to discover whether this had any physiological effect when the data have been studied.

#### No one really cares

"So by "sound barrier" do you mean journalese sloppiness like "the FT index broke the 6000 barrier" or do you actually mean that he will encounter the aeronautic effects of passing through the air that surrounds him faster than sound does?"

Everyone else outside academia (real world) prefers the sloppy version.

#### Re: No one really cares

Considering the number of people who died trying to break the actual sound barrier in an aircraft before we got it right, I'd say it's of more interest if he can do that, rather than just going quite fast.

#### Wings are entirely superfluous in this case

which rather leaves the Red Bull connection redundant

#### Re: Wings are entirely superfluous in this case

Indeed; they were never the same after Denny Laine left.

#### Not quite there yet

Altitude and speed in metric as well as imperial, temperature in centigrade and fahrenheit, but pressure only in PSI?

I also see that El Reg's Standards Soviet has a little bit of ... education to do.

#### Re: Not quite there yet

Not sure about standards soviets, but certainly El. Reg's journos can't be reading the results of their own poll from last week which was resoundingly in favour of stories being in S.I only with the possible exception of pints for beer and ft. for aircraft altitude.

I don't think this story would have counted as having anything to do with "aircraft altitude" in the normal sense of the phrase, and it's certainly not about beer. So the readers' poll seem to have requested it be reported in metric only then.

Fine by me - much easier to read that way.

#### Good luck Felix!

It's quite scary just watching it: God only knows how it feels to be on the edge of space and jump out of relative safety.

#### What could go wrong?

He's only going one direction...it's not as if he has to divert around the roadworks on the M1.

One small leap for mankind.

One serious washing machine for man!

#### SPAAAAAAAAAAAAAAACE

Space. Space. Wanna go to space. Better buy a telescope. Wanna see me. Buy a telescope. Gonna be in space. Are we in space yet? What’s the hold-up? Gotta go to space. Gotta go to SPACE. Ohmygodohmygodohmygod! I’m in space! Wanna go to earth wanna go to earth wanna go to earth wanna go to earth. Wanna go to earth. Wanna go home. It’s too big. Too big. Wanna go home. Wanna go to earth.

#### Re: SPAAAAAAAAAAAAAAACE

ooooh I'm not the only one thinking that the Space Core would definitely hitch a ride on that capsule...

#### Well done!

That was impressive!

....but not out

#### Absolutely Fantastic!!!

I was worried when I saw him tumbling through the sky! Absolutely riveting to watch. I could not sit down.

#### Well done that man!

Ahhh! Woooh! What's happening? Who am I? Why am I here? What's my purpose in life? What do I mean by who am I? Okay okay, calm down calm down get a grip now. Ooh, this is an interesting sensation. What is it? Its a sort of tingling in my... well I suppose I better start finding names for things. Lets call it a... tail! Yeah! Tail! And hey, what's this roaring sound, whooshing past what I'm suddenly gonna call my head? Wind! Is that a good name? It'll do. Yeah, this is really exciting. I'm dizzy with anticipation! Or is it the wind? There's an awful lot of that now isn't it? And what's this thing coming toward me very fast? So big and flat and round, it needs a big wide sounding name like 'Ow', 'Ownge', 'Round', 'Ground'! That's it! Ground! Ha! I wonder if it'll be friends with me? Hello, Ground!

#### Re: Well done that man!

'Oh no, not again.'

#### Re: Well done that man!

So, we have a Portal reference and an H2G2 ref as well! Nice!

Well done lad, was scary watching during those check-lists.

> was scary watching during those check-lists.

He seemed to be struggling to focus. I wonder if there was enough oxygen in the capsule - my in-my-head calculations during the ascent gave a ppO2 of about 0.14, and that's hypoxia territory. Baumgartner seemed to be exhibiting symptoms diuring the checks.

Cracking flight, though. I hope I'll get the opportunity to buy him a beer sometime :-)

Vic.

Suit is pressurised to 3.5psi with 100% O2. So ppO2 =0.24 atm - that's slightly higher than sea level (0.21atm)

> Suit is pressurised to 3.5psi with 100% O2. So ppO2 =0.24 atm

Yes, but was he on the suit breathing system for the ascent?

I noticed when he jumped that they counted down his breathing gas from 10 minutes; that would appear to have been some brinksmanship if he went for 2.5 hours of ascent on the supply, then jumped when it had 10 mins left...

The capsule also measure FO2, and it was higher than normoxic (26%-ish, IIRC). Again, this would be an odd thing to set up if he were doing the ascent on the suit system.

And one of the checklist items was to check the visor seal. This would make no sense if he were already on a closed, internal system.

From the above, I surmise that he performed the ascent on the gas in the capsule, and then qswitched to his suit breathing system just prior to opening the door. And that's why I wondered about the capsule ppO2...

Vic.

According to Wired, Baumgartner was claustrophobic as balls, that's could also be why he behaved odd. Watching him start to spin was terrifying, I think the estimated speed had just maxed out; I worried he'd lost consciousness.

#### No, he was on the cabin system

When they went through the egress (exit) procedures, there were two steps that switched his oxygen from cabin to suit.

We were listening to the audio of the ground staff directly, Felix was listening to it from 20 odd miles away up in the sky.

When Felix spoke the sound was poor, that is what the commands from the ground sounded like to him. Not to mention him being in a suit.

#### Re: No, he was on the cabin system

> there were two steps that switched his oxygen from cabin to suit.

That's what I thought - which means that my ppO2 calcs earlier were appropriate.

That cabin had too little O2 for my liking...

Vic.

The capsule apparently has it's own supply at 8psi as you said and is replenished with LNO2 tanks.

8psi of 100% O2 is ok for a 3.5 hour trip.

My guess is that capsule would start off with air and then vent as it rose until it reached 8psi then continually flow O2 and vent to keep it at 8psi - that way you don't need any CO2 scrubbers and you can gradually off gas the N2 to prevent decompression sickness.

Interestingly the parachute has a way of automatically cutting off the backup - if it deployed accidentally it would slow his descent so much he would run out of suit O2 before he got low enough to breath.

> is replenished with LNO2 tanks.

LNO2? I doubt Nitrous would do much good. But an O2 tank would be easy to strap to the capsule - particularly if it's closed-circuit.

> 8psi of 100% O2 is ok for a 3.5 hour trip.

But that's not what he had if he was breathing the capsule atmosphere; the graphics showed around 8psi at around 26%, IIRC.So rather than having a ppO2 of about 0.54, he would have had a ppO2 of about 0.14. The former would be fine...

> that way you don't need any CO2 scrubbers

Given the rate of expansion of the capsule air - especially at altitude - you're not going to vent much CO2 that way. I, for one, wouldn't risk the problems of hypercapnia for the cost of a scrubber and a loop pump...

> you can gradually off gas the N2 to prevent decompression sickness.

If DCS is a real risk - I haven't done the calculations - it would be much easier to off-gas before the flight.

Vic.

#### Red Bull may give you completely un-needed wings

but it doesn't appear to give you halfway-decent radios

#### So that's one record still in the hands of Kittinger

Longest free fall. (although he used a small drogue chute right from the start of his jump). And it's taken quite a while to break his other records.

Highest balloon ride, highest parachute jump and highest speed go to Felix 'Titanium Cojones' Baumgartner

#### Re: So that's one record still in the hands of Kittinger

Baumgartner also took "Most Boring Two And A Half Hours Of Streaming Youtube Footage"

#### Re: So that's one record still in the hands of Kittinger

Ah you must've woken up after the break in transmission. Whoever fixed that LOS decided to boost the volume while they were at it.

#### not going to let you down

"If something goes wrong, the only thing that might help you is God. . . . and you have to really hope he is not going to let you down."

However, I wouldn't want to be stuck up there either.

#### Re: not going to let you down

Unless you'd achieved escape velocity it's not something you'd have to worry about.

#### Absolutely brilliant

This was one of the most exciting things I have watched for a long time.

It was a fantastic achievement and is one of those things I know I won't forget seeing like the moon landing, which I am just old enough to remember and certainly haven't forgotten.

#### Directions..

I liked it when, after the cute had opened he clearly said "I need directions.."

We knew what he meant, but we were gleefully shouting "Down ! you need to go down"

#### Re: Directions..

chute even

When people do these things just because they can, it renews my faith in humanity.

Huge round of applause to all involved.

Normally I'd say folks who do crazy stuff just to get in the record books are fools, HOWEVER, this guy had a ton of preparation, experience, and purpose behind it. The capsule and cameras recorded all sorts of data that can be useful in future aerospace development, and, hell, he broke the sound barrier without an engine, so it was rewarding in every sense of the word.

/salute and congratulations to him and his team for their accomplishments!

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