Skydiver plans head-first freefall from the edge of space

[Gutboy Barrelhouse]

In dizzying bid to break Mach 1 but he must wear a special suit to ensure his body fluids don't boil.

http://www.dailymail.co.uk/pages/live/articles/news/worldnews.html?in_article_id=474879&in_page_id=1811#StartComments


He will leap head-first from a weather balloon 25 miles above Earth and plummet at more than 1,000mph with only a parachute for company.

He will face external temperatures of minus 100c while inside his carbon-fibre suit it will be a stifling 65c - almost 150 fahrenheit.

And most amazing of all, Michel Fournier is actually looking forward to it.

The daredevil Frenchman, a greyhaired 63-year-old former paratrooper, aims to become the first person to break the sound barrier in free-fall.

As he plunges through the stratosphere at supersonic speed, he also hopes to break three more world records - for the longest sky dive, the highest parachute jump and the highest altitude achieved by a human in a balloon.

Despite the intense cold outside, his £35,000 suit will heat up inside when it meets air resistance. His crash helmet will have its own air supply and reinforced ear pads to protect him from the sonic boom as he breaks through the Mach 1 sound barrier.

Fournier was one of three candidates selected in the 1980s to take part in a military endurance test to see whether a parachutist could descend from 125,000ft - almost 24 miles.

The project was shelved in 1988 - but he decided to go it alone. He hopes to make the jump over the Great Plains of Saskatchewan in Canada some time next month, weather permitting.

"I would be lying if I said I wasn't afraid, but I am also very excited," he said."It really is a leap into the unknown."

After leaping from the balloon, Fournier believes he will break the 760mph sound barrier within 37 seconds.

The lack of friction due to the thinness of the air will mean he can attain a much higher terminal velocity, and his team of scientists estimate he will reach the top speed of 1,113mph before he is slowed down by greater air resistance.

His parachute will not open until six minutes, 25 seconds after jumping and he will finally reach the Earth after around eight and a half minutes.

The record for highest leap was set in 1960 by a U.S. Air Force test pilot, at just under 20 miles.

[Stephen Zepp]

and reinforced ear pads to protect him from the sonic boom as he breaks through the Mach 1 sound barrier.

Heh...hope the rest of his suit design takes into account reality--or at least he gets more technically accurate marketers.

(skimpy source to explain what I mean).

[LK]

I wonder if this will be like Spider-Man 2, the game...

[cmlancas]

and reinforced ear pads to protect him from the sonic boom as he breaks through the Mach 1 sound barrier.

Heh...hope the rest of his suit design takes into account reality--or at least he gets more technically accurate marketers.

(skimpy source to explain what I mean).

Splat. Are we talking 3-2 odds here or just pick 'em?

[WindupAtheist]

[Righ]

and reinforced ear pads to protect him from the sonic boom as he breaks through the Mach 1 sound barrier.

Heh...hope the rest of his suit design takes into account reality--or at least he gets more technically accurate marketers.

(skimpy source to explain what I mean).

I'm willing to bet that that garbage was introduced for (or by) the fluff journalists. You were in the military - you must have spun a few tall stories to explain stuff on your equipment to people who wouldn't understand it without a full lecture series.

[Stephen Zepp]

and reinforced ear pads to protect him from the sonic boom as he breaks through the Mach 1 sound barrier.

Heh...hope the rest of his suit design takes into account reality--or at least he gets more technically accurate marketers.

(skimpy source to explain what I mean).

I'm willing to bet that that garbage was introduced for (or by) the fluff journalists. You were in the military - you must have spun a few tall stories to explain stuff on your equipment to people who wouldn't understand it without a full lecture series.

Heh...I guess I see your point.

I'm just wondering how he's going to both reinforce his bone structure to handle the stress of the displaced layers, and still qualify as freefall (no vehicle).

The other thing that cracked me up is "Fournier believes he will break the 760mph sound barrier within 37 seconds."--as the source I linked also states, the speed of sound changes based on altitude, and that high, it's most likely closer to 500-ish mph (would have to do the math, and know the altitude).

[Roac]

The other thing that cracked me up is "Fournier believes he will break the 760mph sound barrier within 37 seconds."--as the source I linked also states, the speed of sound changes based on altitude, and that high, it's most likely closer to 500-ish mph (would have to do the math, and know the altitude).

The speed of sound is based on air temperature, not altitude.  It is loosely based on altitude only as a function of the general decrease in temperature with height, but that's not always the case; at 25 miles, he will be in the stratosphere which *increases* in temp the higher you go, more or less.  It'll be lowest between the stratosphere and the troposphere or thereabouts, with even the lowest there putting the speed of sound at around 630mph.  However, ignoring drag he'll bust that long before he's fallen that far (around 4mi - edit: I figured 35s, but they've probably put more effort into accuracy).  Between 730 and 760 is a more realistic target for him.

Also of concern is twisting.  At that altitude, there is very little drag.  It's still there, which works on his body just like anything else - air creates pressure which will direct his fall and worse, rotation.  However, it's so much less than what you experience on a more normal dive that inexperience can cause a diver to have difficulty controlling their twisting.  Wouldn't want to turn into the human centrifuge and pass out.

[Strazos]

Or vomit. That would certainly ruin his day.

[Stephen Zepp]

The other thing that cracked me up is "Fournier believes he will break the 760mph sound barrier within 37 seconds."--as the source I linked also states, the speed of sound changes based on altitude, and that high, it's most likely closer to 500-ish mph (would have to do the math, and know the altitude).

The speed of sound is based on air temperature, not altitude.  It is loosely based on altitude only as a function of the general decrease in temperature with height, but that's not always the case; at 25 miles, he will be in the stratosphere which *increases* in temp the higher you go, more or less.  It'll be lowest between the stratosphere and the troposphere or thereabouts, with even the lowest there putting the speed of sound at around 630mph.  However, ignoring drag he'll bust that long before he's fallen that far (around 4mi - edit: I figured 35s, but they've probably put more effort into accuracy).  Between 730 and 760 is a more realistic target for him.

True, and false. While the speed of sound itself is not directly dependent on air pressure (which is the part that is true), indicated air speed (as corrected from true air speed) is, and when in flight (or free-fall),  true airspeed is directly dependent on air density (static vs dynamic pressure calculations form the heart of most mechanical air speed indicators).

I do admit when I made my statement, I was referring to a hypothetical "indicated airspeed" taken from his perspective, not a "distance based travel interval divided by time" which is what people normally think of when talking about speeds. Old pilot perspective and all that.

I know for a fact that my T-38 didn't get much above 470-550-ish knots true at 40,000 feet MSL when I went through the sound barrier. It was more than 18 years ago, so I can't remember the exact number.

[Roac]

I know for a fact that my T-38 didn't get much above 470-550-ish knots true at 40,000 feet MSL when I went through the sound barrier. It was more than 18 years ago, so I can't remember the exact number.

550 knots is around 630mph.  40k feet is just above the tropopause, which is as stated is the coldest part of the atmosphere in this range and where 630mph sound barrier is possible.  Of course, the only thing that matters here is true airspeed; instrumentation errors that state a lower indicated speed don't change physics.  It's not possible to have busted the barrier at 470 knots (true air speed) though; it would require an outside temp of around -200F.

[cmlancas]

I wonder if this will be like Spider-Man 2, the game...

Probably more like McQuaid's career after VG.

Wicked burn.

On a more serious note, can one of you more physics inclined posters list the possibilities of death here? I can't help thinking that even with all the proper planning in the world that there is a terribly large margin of error here.

[Roac]

On a more serious note, can one of you more physics inclined posters list the possibilities of death here? I can't help thinking that even with all the proper planning in the world that there is a terribly large margin of error here.

It isn't so much the speed or height that's an issue.  Air temperature, air pressure, equipment, and fatigue are the main differences from a normal dive.  Fatigue being, he's got to ride for hours to get to where he's going.  Equipment being, it's not typical skydiving gear and may be difficult to manage.  Temp and pressure are both potentially lethal if there is equipment failure.  What to me is really different about this sort of dive is the risk of going into a high rpm spin, which can be lethal.  Also in play are the delta changes, which can be quite rapid.  For example, the body tends to dislike rapid changes in pressure, although I'm assuming the suit is going to deal with this.

[Stephen Zepp]

I'd be most worried about how his suit/body can handle the transition from sub- to trans- to supersonic flight. Depending on his expected body position during those transition phases, he could be generating some really nasty instability conditions related to the chaotic air flows.

Rigid aircraft handle it in a variety of ways (most focused on generating semi-controllable shock waves as early as possible in the direction of flight), but the "standard" free fall position is going to make his belly, nose, and possibly hands/feet cause some really interesting shock waves.

Feet first would probably make most sense, but he still needs to be able to somehow propagate the resultant forces through his body without becoming unstable as Roac mentions.

[Samwise]

I'd be more concerned about being baked at 150 degrees for that entire time, personally.  That seems awfully warm.

[Murgos]

Do we know if it's a rigid suit?  Sounds like it from the description...

[Slayerik]

I'd be more concerned about being baked at 150 degrees for that entire time, personally.  That seems awfully warm.

Better to bake at 150 than get owned by -100

150 is probably like getting in a black car, with black leather seats, after it has roasted in the sun during a 100 degree day. Sure , its miserable...but you could bare if for a while.

[Furiously]

He should bake a cake while he is up in that balloon.

[Strazos]

It's a piece of cake to bake a pretty cake.

[Stephen Zepp]

It's a piece of cake to bake a pretty cake.

hey dude, puff puff pass--get with the program!

[NiX]

So that's what you indies do.

[Oban]

I will wait for the youtube video.