http://www.iht.com/articles/2008/05/23/america/jump.php

Frenchman poised for 'Great Leap,' a 40-kilometer-high adventure

Quote :

"He has spent two decades, and nearly $20 million, in a quest to fly up 40 kilometers to the upper reaches of the atmosphere using a helium balloon, just so he can jump back to Earth again. Now Michel Fournier says he's ready at last to make his "Great Leap." Depending on weather conditions, Fournier, a 64-year-old retired French Army officer, will attempt what he has dubbed Le Grand Saut (The Great Leap) on Sunday over the plains of northern Saskatchewan, Canada. He will climb into the gondola of a helium balloon that when inflated resembles a giant jellyfish. A two-hour journey will take him to 130,000 feet - higher than any balloonist has been before. At that altitude he will see the blackness of space on the horizon and the curvature of Earth below, and experience weightlessness. Then he plans to step out of his capsule wearing only a pressurized suit and a parachute, and plunge to Earth in a mere 15 minutes. If successful, Fournier will fall longer, farther and faster than anyone has in history. Along the way he will accomplish other firsts, breaking the sound barrier and records that have stood for nearly 50 years. "It's not a question of the world records," Fournier wrote by e-mail message through an interpreter from his base in North Battleford, Saskatchewan. "What is important are what the results from the jump will bring to the safety of the conquest of space. However, the main question that is being asked today by all scientists is, 'Can a man survive when crossing the sound barrier?"'"

BTW, what if you fall on to a commercial airliner?

Click to read all.

5/23/2008 9:54:21 PM

Joe Kittinger was a fucking badass. He set the record in 1960 and went on to be POW in Hanoi.

The french guy is pretty badass as well. In an interview he was asked is he was scared of being killed. He responded with something along the lines of "I'm 64. I can die walking down the stairs."

5/23/2008 10:01:16 PM

25 miles
130,000 feet
8 minute free fall
7 minute chute fall
0-700 mph in 40 sec
Top speed: 1,000 mph
Open chute @ 20,000 ft

GOD DAMN

5/23/2008 10:02:20 PM

Yeah he's probably gonna die.

Once he goes supersonic faster than the speed of sound, if he doesn't get knocked out from the shockwave or something else that might happen to a person, he'll experience ridiculous heating due to reentry from adiabatic compression of the atmosphere.

[Edited on May 23, 2008 at 10:04 PM. Reason : Thermotime!]

[Edited on May 23, 2008 at 10:05 PM. Reason : dunno if supersonic = speed of sound ]

5/23/2008 10:03:06 PM

As I understand it, he won't actually break the sound barrier at 1000mph because the extreme low pressure (less than .01 millibar) makes the speed of sound much much higher than that.

[Edited on May 23, 2008 at 10:04 PM. Reason : .]

5/23/2008 10:04:01 PM

Quote :

"In an interview he was asked is he was scared of being killed."

Man, if you die doing that shit, that would SO WORTH IT. You would be the only one in the world who would know what you saw, how it felt (up there and coming down), how your body physically felt (up there and coming down), etc.

I would totally sacrifice myself 100 times over for that knowledge.

5/23/2008 10:04:56 PM

How can he fall faster than terminal velocity of 120mph give or take?

5/23/2008 10:13:02 PM

Imagine going up to him and being like, "Yo, I have done 0-200 mph in 25 sec with my Ferrari/Porsche".

And he says "I have done 0-700 mph in 40 sec... with my body."



[Edited on May 23, 2008 at 10:14 PM. Reason : ^ you DID NOT seriously ask that...]

5/23/2008 10:13:56 PM

http://en.wikipedia.org/wiki/Joseph_Kittinger

5/23/2008 10:15:31 PM

Quote :

"How can he fall faster than terminal velocity of 120mph give or take?"

vt=(2mg/pACd)^1/2

Vt = terminal velocity,
m = mass of the falling object,
g = gravitational acceleration,
Cd = drag coefficient,
p = density of the fluid through which the object is falling, and
A = projected area of the object.

the bold items are variable

[Edited on May 23, 2008 at 10:22 PM. Reason : .]

5/23/2008 10:20:43 PM

I was honestly wondering about terminal velocity myself...

I know the air is thinner and such... but still... terminal velocity is what at 130k?

ok, you gave the formula's... now do the math based on 120mph at 10k feet

[Edited on May 23, 2008 at 10:23 PM. Reason : ^ answered]

5/23/2008 10:22:53 PM

according to http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html

air pressure at 100,000 ft is ~63 times than air at 10,000ft. and that's the highest altitude they have listed.

[Edited on May 23, 2008 at 10:33 PM. Reason : didn't word it right]

5/23/2008 10:30:18 PM

Quote :

"Man, if you die doing that shit, that would SO WORTH IT. You would be the only one in the world who would know what you saw, how it felt (up there and coming down), how your body physically felt (up there and coming down), etc."

The Soviets did something similar after we did Project Excelsior. They're guy jumped out of a balloon around 95,000 feet and smashed his visor open on the last step. Needless to say he didn't make it.

5/23/2008 10:33:20 PM

FUCK. ^ their not they're

Here's the lost cosmonaut.
http://en.wikipedia.org/wiki/Piotr_Dolgov

5/23/2008 11:35:38 PM

Quote :

"Once he goes supersonic faster than the speed of sound, if he doesn't get knocked out from the shockwave or something else that might happen to a person, he'll experience ridiculous heating due to reentry from adiabatic compression of the atmosphere."

Somebody doesn't understand the physics of shockwaves. You are the origination point of the shockwave. You never hear it or feel it.

5/24/2008 12:04:57 AM

Can someone figure out the speed of sound at the altitude he's using with this? My Java is fucked up.

http://www.grc.nasa.gov/WWW/K-12/airplane/sound.html

5/24/2008 12:12:20 AM

^ 723 mph @ 130000 ft
722 @ 129000
721 @ 128000
719 @ 127000

5/24/2008 2:41:51 AM

I was happy with my 14000ft fall.

5/24/2008 2:56:56 AM

Quote :

"Once he goes supersonic faster than the speed of sound, if he doesn't get knocked out from the shockwave or something else that might happen to a person, he'll experience ridiculous heating due to reentry from adiabatic compression of the atmosphere. [Edited on May 23, 2008 at 10:04 PM. Reason : Thermotime!] [Edited on May 23, 2008 at 10:05 PM. Reason : dunno if supersonic = speed of sound ]"

Yes, supersonic = greater than speed of sound. The speed of sound is variable depending on the air density (or air temperature).

And the supersonic heating will not be the same thing that the space shuttle experiences. Realize that the shuttle reenters the atmosphere at almost 17,000 mph. Meteorites can enter the atmosphere at over 20,000 mph. Travelling at hypersonic speeds (~Mach 6 and above) is the cause of superheating. Merely going Mach 1 isn't all that bad.

Check out: http://www.aoe.vt.edu/~devenpor/aoe3114/calc.html
If he's travelling Mach 1.1 and produces a normal (perpendicular) shock wave, the T2/T1 ratio (temperature after shock wave / temperature before shock wave) is a whopping 1.06. (Do your calculations in Kelvin or Rankine, not F or C -- that would result in colder temps after the wave than before.) So that would be an increase of just a couple of degrees.

You can also see that the pressure (P2/P1) increases by about 25% and the density (rho2/rho1) increases by 17%.

The transition from non-shocked to shocked flow will not be very severe for him. There will be a change in density big enough to make his ears pop (if he wasn't in a pressurized space suit, that is), but nothing beyond that will be very noticeable.


Now, if he were to hit hypersonic speeds, or hell, even a Mach of 2.0, then there would be some nasty effects. At M=2, the pressure will increase 450% over ambient, and the temperature will increase 69%. (If we say -50 deg C, that's 223 K, * 1.69 = 376 K, or 102 deg C, or 217 deg F)
That kind of change can fuck you up.
But he's not going to hit Mach 2.

[Edited on May 24, 2008 at 11:34 AM. Reason : link]

[Edited on May 24, 2008 at 11:36 AM. Reason : at speeds close to M=1, the shock angle should be close to normal, don't worry about oblique shocks]

5/24/2008 11:33:00 AM

Quote :

"As I understand it, he won't actually break the sound barrier at 1000mph because the extreme low pressure (less than .01 millibar) makes the speed of sound much much higher than that."

now ask yourself, considering the physics of sound, how would lower pressure increase its speed?


I'd really be interested in putting a microphone at the farthest reaches of our atmosphere, where the various atoms of "air" cease to be able to propagate sound waves, and see what happens.

5/24/2008 12:51:54 PM

^ You're exactly right. Durrrrr on my part.

5/24/2008 2:54:18 PM

I wouldn't mind going out this way.

5/24/2008 3:57:56 PM

Where can I sign up for the second jump?

5/24/2008 5:18:19 PM

so what happens to the balloon after he jumps?

and can you breathe at that altitude? oxygen integrated into pressure suit and helmet

[Edited on May 24, 2008 at 5:33 PM. Reason : but what about the balloon?!?!]

5/24/2008 5:28:42 PM

^ NASA experimented with that kind of decompression in the 50s. Subjects reported feeling the saliva in their mouth boil as they blacked out.

[Edited on May 24, 2008 at 7:20 PM. Reason : .]

5/24/2008 7:20:46 PM

^^^^^ from wikipedia: (I was curious)

Quote :

"The speed of sound is variable and depends mainly on the temperature and the properties of the substance through of which the wave is traveling. For example, in low molecular weight gases, such as helium, sound propagates faster compared to heavier gases, such as xenon. In a given ideal gas the sound speed depends only on its temperature. At a constant temperature, the ideal gas pressure has no effect on the speed of sound, because pressure and density (also proportional to pressure) have equal but opposite effects on the speed of sound, and the two contributions cancel out exactly. In non-ideal gases, such as a van der Waals gas, the proportionality is not exact, and there is a slight dependence on the gas pressure, even at a constant temperature. Humidity also has a small, but measurable effect on sound speed (increase of about 0.1%-0.6%), because some oxygen and nitrogen molecules of the air are replaced by the lighter molecules of water. "

5/24/2008 7:35:05 PM

Cool video of Kittinger's 1960 jump from 102k feet.

http://www.youtube.com/watch?v=9MkB6NkQscI

You can find some more informative ones if you search for "Project Excelsior".

5/24/2008 8:03:59 PM

^That was a crazy video. I also like the 5 second transition at the water surface from parachute-harnessed pressurized suit to a half-naked guy with a surfboard.

5/24/2008 11:09:44 PM

^^^ In normal air (I don't know if the air is "normal" at 40km), the speed of sound is actually solely a function of temperature:

a = sqrt[gamma*R*T]

a = speed of sound
gamma = ratio of specific heats or something = 1.4
R = Rydberg Gas Constant = 287.09
T = Temp in Kelvin

(The thing about Pressure and Density exactly cancelling out is just from the ideal gas law: P*V = n*R*T or P*m = rho*R*T: P and rho cancel out and T is the only variable remaining)

Way up high the temp is wickedly cold. Maybe -50deg C or 223 K:
a = 299 m/s = 670 mph

at normal temps of 22deg C or 295 K:
a = 344 m/s = 770 mph


At a speed of sound of 670 mph and a supposed top speed of 1000 mph, that's a Mach number of 1.50
Using the link I provided above and assuming a normal shock:
T2/T1 = 1.32
P2/P1 = 2.46
rho2/rho1 = 1.86

When the shock develops, it would pop the hell out of his ears, but the pressure up there is so damn low to begin with, it'll just start to approach normal pressures. Plus he'll be in a space suit, so no worries.

5/24/2008 11:28:09 PM

If i was going to die that is the way i would like to go

5/24/2008 11:51:34 PM

nvm

[Edited on May 25, 2008 at 1:24 AM. Reason : ]

5/25/2008 1:22:17 AM

I guess it would be terrible to get off course by some high-level winds and fall through a cloud full of hail stones the size of golf balls.

5/25/2008 1:48:57 AM

Quote :

"That was a crazy video. I also like the 5 second transition at the water surface from parachute-harnessed pressurized suit to a half-naked guy with a surfboard."

Sorry man. It looks like every asswipe with a computer has tried to turn the video into some mega queer music video. That was the best that I could find.

5/25/2008 3:41:14 AM

Quote :

"Top speed: 1,000 mph"

jeebus!

that kittinger vid was sweet too btw.

5/25/2008 11:46:07 AM

5/25/2008 12:38:06 PM

Quote :

"How can he fall faster than terminal velocity of 120mph give or take?"

In a normal atmosphere freefall it's a function of area. If you are belly to earth cupping air with your arms and legs extended you fall very slow, maybe 100 mph for an average sized person. if you bring your arms in and push your hips as far forward as you can you can hit 125 - 130. If you are head down (toward earth) with arms and legs out you fall about 140 and if you bring everything in with legs together and steer with just your hands you can hit 300. I hit just over 220 yesterday diving to a group (I left the plane about 2 seconds after they did).

All the speed changes gives the impression of a person going up or down. That's why it feels like flying and not falling.

5/25/2008 1:10:32 PM

fuck that

5/25/2008 1:10:39 PM

^^^ That was my PC wallpaper for a long time. Excelsior has amazed me for a long time.

5/25/2008 1:15:42 PM

Quote :

"Travelling at hypersonic speeds (~Mach 6 and above) is the cause of superheating. Merely going Mach 1 isn't all that bad."

The way we were taught in class is that superheating of the shuttle comes from the adiabatic compression of the atmosphere at speeds higher than the speed of sound, because at that speed the air molecules can't move out of the way of the shuttle fast enough. I didn't realize it had to be that high though, why is that?

We only spent like 5 minutes on the topic, and then wrote a short paper for our final exam on the topic.

5/25/2008 3:56:06 PM

Wasn't this supposed to happen today?

5/25/2008 5:26:51 PM

doesn't look like it, from another article:

Quote :

"If all goes according to plan, at 2 a.m. Monday morning the 64-year-old Fournier will climb into a capsule below a towering helium balloon. Launch was scheduled for 5 a.m. and 2 1/2 hours later from an altitude of 130,000 feet or 40 kilometres over the flat expanse of the Saskatchewan prairie, he would open the door. And jump."

Quote :

"Low-resolution images from the capsule will be broadcast to Fournier's ground station in real time."

LINKPLZ

[Edited on May 25, 2008 at 11:48 PM. Reason : ]

looks like a webcam will popup here at some point

http://www.legrandsaut.org/index.php?lang=eng

[Edited on May 25, 2008 at 11:51 PM. Reason : bottom right]

from his blog:

Quote :

"Translation: French » English Go a little patience, my webmasters arrive tonight at 18h00 (14h30 is at this time) tomorrow page news will be opened, you will enjoy. Michel"

10:30 at blog post

so i guess this is happening sometime tomorrow..

[Edited on May 25, 2008 at 11:54 PM. Reason : ]

5/25/2008 11:47:31 PM

Quote :

"The way we were taught in class is that superheating of the shuttle comes from the adiabatic compression of the atmosphere at speeds higher than the speed of sound, because at that speed the air molecules can't move out of the way of the shuttle fast enough. I didn't realize it had to be that high though, why is that?"

Temperature changes in some sort of exponential relationship with the Mach number of the moving body. A Mach of 1.1 produces a just barely noticeable change in temperature. Mach 2 is uncomfortable (1.7x original temp (use Kelvin or Rankine)). Mach 4 starts to get pretty damn nasty (4x original temp). Then all hell starts breaking loose. Mach 8 is 13x, Mach 10 is 20x, Mach 20 is 80x.

Your understanding is pretty much correct. In subsonic flow, the oncoming air can "see" or "hear" the approaching vehicle because the pressure perturbations caused by the vehicle travel forward at the speed of sound and "warn" the air that something is coming.
In supersonic flow, the vehicle is travelling faster than the air can transmit information. Thus, any air in front of the vehicle has no idea that it's about to get slammed by some body until it's too late, and kablammo happens. The kablammo manifests itself in the form of a shock wave. A shock wave is essentially a discontinuity in the flow where the temperature, pressure, and density of the fluid change damn near instantaneously.

5/26/2008 12:20:32 AM

Quote :

"Sorry man. It looks like every asswipe with a computer has tried to turn the video into some mega queer music video. That was the best that I could find."

You obviously didnt look to hard. The video at the top of the "related videos" list is this one, which is way better than the one you posted.

http://www.youtube.com/watch?v=81gn2oLeC_U&feature=related

5/26/2008 12:39:44 AM

Oh snap! I suppose that I just got served!

I saw that one. I just wanted to post a short video of the jump itself, not a long quasi-documentary.

[Edited on May 26, 2008 at 2:17 AM. Reason : .]

5/26/2008 2:09:26 AM

that is a fucking awesome song anyway


boards of canada- dayvan cowboy

5/26/2008 3:30:14 AM

the whole speed of sound thing is lame...why cant he just fall and have some fun but noooooooo...hes got to worry about "the speed of sound"

5/26/2008 3:45:44 AM

inorite

coldplay sucks

5/26/2008 3:53:15 AM

the link in this thread is dead/getting hammered right now... yesterday they said today should be a go, and gave some crazy amount of seconds till go time

i didnt bother to do the math then cause it wasnt until at least today, but any idea on exactly what time they're going for with this. i'm very curious about this stuff. pretty neat "hobby".

5/26/2008 7:07:02 AM

You have to pay to view the webcam

5/26/2008 10:17:46 AM

Set us up the bomb

and we should see the results of this shindig tonight unless he calls it off.

5/26/2008 7:52:10 PM