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Skydiver To Break Sound Barrier During Free-Fall
Hugh Pickens writes "Over fifty years ago, American Joe Kittinger made history by leaping from a balloon at 102,800 ft, and although many have sought to repeat the feat, all have failed. Now, BBC reports that Austrian extreme sportsman Felix Baumgartner will try to break the long-standing record for the highest ever parachute jump, skydiving from a balloon sent to at least 120,000 ft, and it is likely that 35 seconds into in his long free-fall of more than five minutes, he will exceed the speed of sound — the first person to do so without the aid of a machine. 'No-one really knows what that will be like,' says Baumgartner. Although challenges in the endeavor include coping with freezing temperatures and ultra-thin air, a key objective for Baumgartner will be to try to maintain a good attitude during the descent and prevent his body from going into a spin and blacking out. 'The fact is you have a lot of different airflows coming around your body; and some parts of your body are in supersonic flow and some parts are in transonic flow. What kind of reaction that creates, I can't tell you,' adds Baumgartner."
I suspected, and breaking slashdot rules and reading TFA confirmed, that his suit is designed to automatically deploy the parachute at some failsafe altitude, even if he blacks out earlier.
Still plenty of room for things to go wrong, people manage to die doing perfectly ordinary parachuting from time to time; but probably more dramatic than dangerous.
If there's enough atmosphere to lift a balloon, there's enough atmosphere to transmit sound.
http://alternatives.rzero.com/
To go that fast, he will need to be extremely streamlined. Air becomes incompressible at supersonic speeds, so either his feet or head will need to handle the friction and stress created. I'd want a stability bar running the length of my body that my feet, legs, torso, shoulders, arms and head "clip" into.
To get out of that streamlined attitude is easy. To get out of it safely is a different matter completely. I'd want a way to release a trailing parachute, attached to my shoulders, to bleed off most of the speed. Perhaps down to 200 mph.
Slowing from 1200+ fps to 120 fps is a big deal and without extremely careful methods to retain something call static stability http://en.wikipedia.org/wiki/Longitudinal_static_stability and he will end up tumbling out of control, breaking limbs or worse.
Any way, I wanna watch. I hope he does the trailing smoke thing!
Star Trek: The Motion Picture (Star Trek 1)
Star Trek II: The Wrath of Khan (Star Trek 2)
Star Trek III: The Search for Spock (Star Trek 3)
Star Trek IV: The Voyage Home (Star Trek 4)
Star Trek V: The Final Frontier (Star Trek 5)
Star Trek VI: The Undiscovered Country (Star Trek 6)
Star Trek: Generations (Star Trek 7)
Star Trek: First Contact (Star Trek 8)
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Star Trek: Nemesis (Star Trek 10)
Star Trek (2009 - Star Trek 11)
While movies 2 through 4 were one story arc, they were three separate movies with each done by different directors. Hence, that's why we are at Star Trek 11. Talks are under way for #12 with the revamping of the franchise.
Meh, it's a question of technicalities. Gravity is the force that will cause him to break the sound barrier (and perhaps the thin air - lack of resistance). A machine will not be used to accelerate him. It will give him tremendous potential energy, however. Anybody want to calculate that?
About 26 megajoule.
(If you want to check the calculation: His weight is 73 kg)
The Tao of math: The numbers you can count are not the real numbers.
I'm sure they mean the speed of sound at his particular altitude. Joe Kittenger reached 614 mph during his freefall in the 1960, which is roughly Mach 0.8 at sea level. At around 35,000 feet the speed of sound drops to around 650 mph. At higher altitudes, the speed of sound actually increases for awhile.
They've had supersonic ejection seats for quite a while now. Pretty much every modern fighter jet has them. There was a successful ejection out of a modified SR-71 back in the 60s. They were flying at over mach 3. Pilot survived, the copilot drowned when after he landed in the water.
Pretty good information about high-altitude skydiving here: Speed of a Skydiver
http://www.geoffreylandis.com
Apparently you never learned about significant figures.
Obligatory Franz Reichelt attempting to fly off the Eiffel Tower reference.
Graphic Video Warning: He does not miss the ground.
The speed of sound seems to hit a minimum (over the range of altitudes he'll be falling through) in the Tropopause between 40 and 65000 ft (12 and 20000 m) at about 970 ft/s (295 m/s).
http://www.aerospaceweb.org/question/atmosphere/q0112.shtml
In The Long, Lonely Leap Kittenger claims a radar-checked top speed of 274 m/s which is getting pretty close to Mach 1 at at least some of the Baumgartner he'll be falling through. The extra 18000 ft (5500 m) he'll fall may be enough in the thin air up there to do it.
The guy's starting at over 36km. Air pressure is about one 200th that of surface pressure. Given that the acceleration needed to counter drag increases with velocity^2 (if you're going twice as fast, twice as many air particles hit you at twice the relative velocity), that means that terminal velocity is 14 times as high as usual. Terminal velocity at the surface for a mostly vertical human with gear (I estimated 0.30m^2) is 200 m/s, so up there the terminal velocity is over 2800 m/s, or about 9.5 times the speed of sound at that elevation.
Those stats are a little out of date, here are the new ones:
1: 6.2
2: 7.8
3: 6.5
4: 7.3
5: 4.9
6: 7.2
7: 6.5
8: 7.6
9: 6.4
10: 6.4
11: 8.2
The new numbers give a U value of 7.5, which is completely attributable to the latest two movies. Note that 11 is the highest rated by far (adding 5 to the U value) while 10 is lower than 7 and 3 (so it can take credit for adding 2.5 to the U value). I'd say that in addition to rebooting the Star Trek franchise, 11 has rebooted the pattern.