Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Space

Sub-Orbital Skydiving 372

Posted by timothy from the it's-a-long-long-way dept.
igz writes: "Someone is trying to set the world record for highest freefall, from over 31 miles above the Earth! There is no atmosphere up there, so speeds of up to 1.5 Mach are expected. Check it here." Whether this is insanity or courage is up to you, but it sure sounds like a fun ride. Cheryl Stearns is the insane / courageous diver, and she will jump wearing a pressure suit to counter the lack of air at (gulp!)165,000 feet up.
This discussion has been archived. No new comments can be posted.

Sub-Orbital Skydiving More

Sub-Orbital Skydiving

Comments Filter:

  • -wow- (Score:2)

    by XO ( 250276 )
    All I can say is that this chica must've rolled really low on her INT or WIS rolls when she was created.

    Roll saving throws versus DEX to avoid air turbulence. Fail, a hole is ripped in your spacesuit at 165,000 feet up, bam, you're dead. Succeed, and roll save vs CON to avoid passing out.

    Can you imagine what the GROUND must look like coming at you at Mach 1 though?!??!?
  • "There's very little room for error," says Stearns. "This is not an easy endeavor - that's why it hasn't been done yet."

    1. get pressurized suit
    2. get plane really high
    3. jump out of plane

    Hitting the ground at Mack 1.5: Priceless
  • 31 miles above the Earth? THAT's a long way down! She should take her Palm pilot with her in case she gets bored. You know, a quick hand of Mahjongg around 20,000 feet.
    She's going to find life kinda boring after doing something like that, I would think. I mean, what would you do to top that??
  • Doesn't it take as much energy to stop a body in motion as it took to set it in motion?

    Let's see now, an object as heavy as the shuttle, going 17,000 miles/hour. Now how much energy did it take to get it up to that speed?

    Stopping it is impractical, unless you want to carry along another large supply of fuel (which makes getting that extra fuel into orbit even harder to begin with, we're talking something like $10,000 per pound here).

    Of course, the idea of just stopping, and then slowly falling out of orbit might be okay if you have virtually unlimited energy available, ala Star Trek. (And sufficient propellent mass to expel at high speed -- or some other way to push or pull not involving expelling mass at high speed.)

  • Skydiving Records... (Score:5)

    by Schwarzchild ( 225794 ) on Thursday November 02, 2000 @12:22AM (#655857)
    Capt. Joseph Kittinger jumped from 102,800 feet in 1960. Another skydiver Piantanida jumped from 123,500 feet in 1966 but his altitude record was not recognized I think because they were not sure he actually made that altitude (his altimeter may have stopped working).

    A simulation of the Kittinger dive [pbs.org] is on the NOVA website. Plus they also show the famous picture of him jumping out of the gondola.

    Also there is a really great book written by Craig Ryan called The Pre-Astronauts [amazon.com]. The Pre-Astronauts is all about the history of high altitude skydiving. A cool quote by Alan Shepard from the book when asked if he would have done the Kittinger jump: "Hell no. Absolutely not."

    Another cool fact is that Capt. Kittinger's boss during those high skyjumps was no other than John Paul Stapp the guy who is always in those famous pictures and movies of the rocket sled. Remember those pictures of a man's face being progressively made more distorted by g-forces? That's John Paul Stapp!

  • For the ultimate adrenaline rush, check out Project MOOSE [friends-partners.org]. A system that was developed in the early 60's that would have enabled a person wearing a space suit to re-enter the atmosphere and land from low Earth orbit.
  • Yeah. I'm sure she just has no idea about things like oxygen or heat or cold or pressure. I bet she just has no clue.
    Gimme a break.

    1) pressure suit.
    2) Woudl not burn up, or burn at all. This is not someone entering the atmosphere at tens of thousands of mph.
    3) no friction until much lower anyway.. the air is so thin the suit won't even flutter.
    4) cold: Pressure suit is insulating. Also, thin atmosphere is ALSO insulating. It's the cold at lower elevations that might be dangerous.

    Why would she black out, if she's in a pressure suit with an air supply? I don't figure.

  • She'll experience *NO* acceleration, she'll be in freefall. She will experience decelleration as the atmosphere thickens (and when she opens here chute).

  • I don't know much (read *anything*) about skydiving but it said in the article that the big danger was that she would go into an uncontrolled spin because there was no air for her to use to control her fall. I was Wondering if It might be plausible for her to carry down a gyroscope for the first while in order to stabilize herself, and then ditch it (let go of it and have it open up a drag shoot) when she gets down where there is some air for her to control herself with? just an Idea

  • Re:Extinction... (Score:3)

    by GeorgeH ( 5469 ) on Thursday November 02, 2000 @05:55AM (#655873) Homepage Journal
    Mach 1.5? Everyone knows that to travel in time you need to be going 88 Mph!

    Now how is she going to generate the 1.21 gigawatts of electricity?
    --
  • Michel Fournier is also attempting something similar. Details etc on his website at http://www.legrandsaut.com [legrandsaut.com]

    Does anyone know how high Gary Powers was when he bailed out of his U2? That must have been a pretty high jump.

  • Never. Without oxygen, you die, period.

    You worry about heat when you are going about ten times faster than this lady will be going.

    Remember, orbital vehicles don't simply 'fall'.. they come out of orbit (fast). It's their lateral speed around the planet through atmosphere, not the vertical vector that really causes that red-hot friction.
  • Remember.. mach 1.5 at what altitude? Mach 1.5 is a half mile/second near sea level. at 100,000 feet, mach is WAY slower, so going 'mach' means a lot less.

    Thinka bout it.. at lower altitudes, there is now ay you could achieve mach in freefall... way too much air resistance, but as you go higher, mach drops, and air resistance drops, so it gets so easy.

  • I wonder if you can get adrenaline poisoning?

    You wouldn't need coffee for weeks after doing this would you?

  • They are quoting the speed in Mach numbers to make the speed sound more impressive than it is...

    The speed of sound changes with air density - if the air density is zero (as in space) then the speed of sound is zero m/s, the air density is very thin high so the speed of sound will be very low. So if you quote this womans speed in mach numbers as she falls then she will start off at mach 1.5 and then slow down to about mach 0.5 (I seem to remember that people fall at about 200m/s through air close to the ground). In reality the actual speed change will probably be from about 250m/s to 200m/s.

  • And besides, there will be air eventually... I'd say there's a good chance she'll be going a hefty speed when she hits it.

    Woz
  • "Once that drag exceeds the force of gravity, she'll start to slow down, producing less drag. So her drag will never significantly exceed enough to counteract gravity."

    translation: she won't float. no kidding.

    My .02,

  • Ok, but the question in my mind ...

    If Mach 1 = speed of sound at sea level, does it really follow that the MPH speed of Mach 1 changes with altitude? Sure, the speed of sound varies with altitude, but isn't Mach 1 just a reference number for velocity?

    I guess not since in 'The right stuff' Yeager produced a sonic boom as he passed M1 in the desert and was obviously not at sea level. So, how does that work? He had a M indicator in his X-1 cockpit that I guess was an airspeed indicator that had to adjust for his altitude in determining where the plane was relative to M1?

    But then again, this speed of sound calculator [demon.co.uk] only asks for temperature and humidity, not altitude in determining the speed of sound.

  • damn, hope she doesn't hit a bird. . .
  • ...that one of the higher of all free-falls was the pilot who got shot down in the U2 over Russia. Apparently he had to free-fall for quite a while before opening his parachute, because he only had 10 minutes of oxygen, and if he deployed his chute right away, the oxygen would have run out before he had fallen to a breathable altitude. I don't know how long he did fall, though.
  • static electricity from air friction.

    (that may actually be a problem. . .)
  • Hmm ... how about this. Ride the shuttle up, park the shuttle in a geosynchronous orbit, and make your "dive" by jumping out of the cargo bay towards the earth.

    This really does push the notion of "extreme sports" to a new level!
  • the sound of one bitch slapping
  • I saw one of those shows on the early space race where they had video footage of a guy testing a pressure suit by floating to a height of over 100,000 feet under a balloon. I was watching the footage (camera above the gondala) thinking "How the hell is he planning to get down" when he just jumped. And certainly free fell for a long, long way. So although it probably wasn't 165000 feet then all that stuff about "First time anything like this has been attempted" is bollocks.
  • but is she hot?
  • Yes, but a "skydiver" who doesn't turn into a "parachutist" becomes a "crater" instead.

  • Re:Mach 1.5? (Score:4)

    by Andy_R ( 114137 ) on Thursday November 02, 2000 @03:26AM (#655931) Homepage Journal
    As you say, a lone parachuter makes a lot less noise than a plane, however to be on the safe side, I guess she should limit the length of time for which she shouts "Geronimoooooooooooooooooo...." to the point where she reaches (say) mach 0 .95

    However, in the interests of science, I think she should take the risk of shouting it briefly just before reaching Mach 1, so she can be able to hear herself going "oooooooominoreG" shortly after.

  • Mach 1.5!!

    Why jump out of a perfectly good balloon anyway? It's not on fire, it's not going to crash...why get out?

    Not to mention the fact that she doesn't have silica tiles like the shuttle, if she starts to glow upon re-entry at mach 1.5, that would be a "Bad Thing"(tm).

  • The article says that it's not a problem like a Space Shuttle experiences, because she's not traveling at orbital speed...
  • on another note, most people never exceede the speed of sound in their lifetime. The lucky few are military pilots and those that can afford and justify a ticket on the concord. This lady gets to do it without a plane.

    That leads to my question -- what effect will the (presumed) sonic boom have on her without a plane to shield her from it? Is it dangerous to either her body or her hearing, or will she even notice it? Or will there be no sonic boom at all, with so little atmosphere?

    Enquiring minds want to know...

  • Re:Do it right! (Score:3)

    by PhatKat ( 78180 ) on Thursday November 02, 2000 @03:29AM (#655943) Homepage
    Pressurized suit: $20,000
    Extremely high altitude flight: $15,000
    Used parachute: $40
    Patches for parachute: $5.37

    Becoming the biggest Jackson Pollack painting ever: priceless.

  • Pressure suit? Reentry heat tiles? (Score:4)

    by Speare ( 84249 ) on Wednesday November 01, 2000 @08:37PM (#655947) Homepage Journal

    At what point do you need to stop worrying about oxygen, so much as worrying about re-entry friction?

  • There was a book written a few years ago by Tom Read called 'Freefall' which goes into this subject in some detail. I'll basically give you the synopsis of the interesting technical bits here, so that you can all stop guessing (which is what you are doing).

    Firstly, Joe Kittinger had the highest recorded jump, but it is not an official record, as it was not witnessed by an independant judge. Tom Read went out and visited Joe as research for his own jump (there is a weird bit in the book about how Joe drives around Florida in a London black-cab painted white, but anyway).

    The plan was for Tom to jump from about 120,000 feet from a gondola. At that height there is virtually no air, and therefore there are lots of problems. Firstly the jump would have to be made in a pressurised suit which is cumbersome, and the only suit suitable from a Russian company restricts joint movement at the elbow, which if you're a sky diver, is a major problem. In addition, because the air is so thin, stability is uncertain. Therefore a drogue parachute is really a must for stability, but this will cause the drop to be slower than without the drogue. This causes problems if you're trying to break Mach 1.

    With regards to breaking Mach 1, there are a couple of major issues none of you have taken into account. Firstly, the speed of Mach 1 depends on altitude - at sea level it is a great deal faster than it is even just at 10,000 feet. At 120,000 feet it's less than 690mph. Therefore, if you aren't packing a drogue, then you're going to find it a great deal easier to get through that barrier, but there are still other problems.

    There is a region of speed which I think is called the tran-sonic region. This is just before reaching the speed of sound and is when the air pressure in front of the object is building up. People don't notice this effect on Concorde because of the acceleration making it such a short period. When you get to Mach 1, the buffeting suddenly stops, and you can accelerate much easier.

    People have stated that there is no air at this altitude, and that's just pure crap - there is air, just not a lot. There is a risk that one part of the body will reach Mach before another and that may cause problems. In theory, there is a chance that trying to do this will cause your head to be pushed back into your neck - this would of course be fatal.

    Tom Read unfortunately had a mental breakdown (which is what a large part of his book covers), which isn't suprising considering some of the jobs he did whilst a Para and in the SAS, and trying to plan for doing this sort of jump. I would reccomend however trying to grab a copy of his book if you're interested in this subject, as those sections that do cover the plans for the jump, although brief, make quite interesting reading.

    All I can say, is that it would require a highly experienced sky diver, preferably with military background and over a 1,000 jumps at minimum to try this one. Personally, I've always thought that the ultimate would be Angel Falls as a basejump, which I know goes on quite regulraly. Looks fantastic.

  • Re:Human versus jet aircraft (Score:4)

    by digitalwanderer ( 49695 ) on Wednesday November 01, 2000 @10:55PM (#655951) Homepage Journal
    Hey! You were wrong, the cat dies too. (And boy is my wife PISSED at me now!)

  • Re:umm (Score:2)

    by jafac ( 1449 )
    80,000 or so. Doesn't necessarily mean he bailed out that high.
  • Kittinger, if I recall correctly, also broke the sound barrier on the way down. I think that he's still the only person, so far, to go faster than mach 1 without a vehicle.
  • hmm yeah, hence the old jet pack thing to use to break relative to the earth when getting closer.

    Kind of like crossing a roundabout from a point on the outside to a point opposite on the inside, you would appear to be moving in a straight line between the 2 points, but actually going diagonally against the rotation.

    Then again the math would be hell, and I'm sure if it was possible they'd have already tried bringing spacecraft in that way as there must be advantages to doing it at mach 1.5 rather than mach 15 (or 30 whichever of the above was right)

  • IIRC, an interesting fact about the U-2 is that since it cannot break the sound barrier, there's a specific altitude and speed it can fly at. If it flies higher, then there isn't enough air to provide lift, so it stalls. If it flies faster, it's supersonic, if it flies slower, again, not enough lift and it stalls, and the safty margin at it's maximum altitude between stalling and supersonic was like 1 mph. So it took a very skilled and precise pilot.
  • There is also a website for Cheryl Stearns jump at Stratoquest.com [208.56.77.49]. Aparently the jump was going to be filmed for a TV series called "Global Fitness Challenge [208.56.77.49]". (However, that mentions an April 2000 date?) The common theme of the show seems to be pitting an American athlete or team against a foreign competitor.

    RE: Gary Powers
    Though the U2 was capable of flying at 80,000' and routinely flew at 70,000, Powers plane had already dropped to 34,000 feet when he climbed out. (read Mayday for the U2 [military.com] for a detailed retelling of Powers flight).

  • Re:Question... (Score:3)

    by rasilon ( 18267 ) on Thursday November 02, 2000 @03:56AM (#655966) Homepage
    It isn't actually outside the atmosphere, there is just very little air. You use huge balloons - have a look at Lindstrand Balloons [lindstrand.co.uk], they do lots of pioneering stuff like the ballooning equivalent of satelites and heavy lift airships. Actually, there is a very good chance that they will make this balloon. Either them or Cameron Balloons [cameronballoons.co.uk].
  • this isn't the only dangerous jump that has been conducted in the last couple of years

    actually sometime back in '97 several very experienced skydivers decided to do a very high altitude jump over antartica.....

    however bravado got in the way and none of them used automatic releases for thier chutes (where an altimiter trigers the release) or carried altimiters

    due to the overcast conditions and well the simple lack of contrast between sky and ground out there in iceville.....several of them died when they tunneled straight into the snow without even having deployed thier chutes.....they simply had no idea the ground was even comming and eneded up 30 feet deep.

  • About The Record This Would Be Breaking (Score:4)

    by DoasFu ( 99077 ) <bennettdNO@SPAMgmail.com> on Wednesday November 01, 2000 @08:38PM (#655972)
    This would be an amazin accomplishment, but it should be noted that this would not be the first dive from an altitude high enough to require a pressure suit. Forty years ago Joseph Kittinger made a succesfull jump from 103,000'. A quick google search turned up some sites with info on him and his jump. Check some of them out:

    Here [af.mil]
    and

    Here [ohio-state.edu]and
    Here [balloonlife.com]Dan
  • Actually, the speed of sound goes UP as the air pressure goes down. At sea level, Mach 1 is roughly 700 miles/hour, while at 100,000 feet where the Habu fly it's about 1000 miles/hour.
  • People keep talking about the heat buildup at Mach 1.5. You forget the Sonic Wind series of experiments: Strap a fool to a rocket-powered sled on rails and light the fuse. Fool and sled exceed Mach 1. Fool and sled hit pool of water and slow down at 20 g's plus.

    They have video of this up at the Cosmosphere [cosmo.org], but unfortunatly not online. You can actually see the shockwaves from the leading edge of the fool!

  • Do it right! (Score:5)

    by TheDullBlade ( 28998 ) on Wednesday November 01, 2000 @08:39PM (#655981)
    Pressurized suit: $20,000
    Extremely high altitude flight: $15,000
    Used parachute: $40
    Patches for parachute: $5.37

    Being the first person to achievesubterranean supersonic travel: priceless.

    --------
  • Why would she black out? She has a pressure suit. There will be no extreme heat. The highest speed she'll attain is mach 1.5. Space shuttle re-enters at around mach 15. (No decimal point.) Airplanes at that speed don't have too much trouble with it. Whatever heat there may be, along with the cold, is also presumably taken care of by the pressure suit.

  • technicalities (Score:2)

    by Anonymous Coward
    • looking at the picture of her in the specialized jump suit, skin shows. Now if your so high up, that there's not enough air to control descent, then isn't there any danger of bends sickness if the whole body isn't in a preassurized suit?
    • one not only needs a preassurized suit. I would imagine you also need a suit that protects one from cosmic radiation...?
    • what about becoming extremely electro statically charged by falling at those speeds and "ripping" the atmosphere which is busy absorbing radiation..?
    • it is extremely cold up there, somewhere around -90 celcius, add to that the draft chill factor of mach 1.5 ...
    • one poster mentioned the danger of airplanes wings being ripped of at such high speeds. That danger doesn't apply here since in the case of the airplane the accelerating force is being applied to the "trunk" of the airplane from behind, thus straining attached parts not in front of the engine. In the womens case, the accelerating force is gravition, which is being applied to her whole body. But what about resonance effects? Assuming she can avoid going into extreme tumbling wouldn't there be a problem of "whipping" body parts (her head for example) ..? The extreme tumbling could lead to vomitting into her helmet and suffocating?
    • basically what happens is her potential energy of 31miles gets converted into other forms of energy: thermal and kinetic. No need to worry about the thermal energy part. So, the kinetic energy would be preferrably "down". But she also has three axes of rotation. Entropy usually is quite eager to take advantage of all dimensions of freedom. Ok, so she uses some kind of drag-chute. That still leaves on dimension of rotational freedom left: spinning along the axis of head to feet. (Which brings back the possibility of vomitting into her helmet again.)
    tom in hd

  • Re:hmm (Score:2)

    by jms ( 11418 )
    I loved that ride! Nothing like staring up at a little round movie screen while your butt is pinched as the rocket "blasts off!"

    I don't remember the part you're talking about though.

  • Extinction... (Score:5)

    by ijx ( 66809 ) on Wednesday November 01, 2000 @08:41PM (#656003)
    Several Million, B.C: great lizards known as "Dino-saurs" were rendered extinct by the impact of a meteorite off the Yucatan.

    2000: Parachutist Cheryl Stearns achieves the first sub-orbital skydive, with mixed results. When she reached Mach 1.5, Cheryl vanished, never to be seen again.

    2020: It has been determined that Cheryl Stearns, upon breaking mach 1.5, travelled through time, and smashed into the Yucatan. The resulting clouds and debris led to the extinction of all dinosaurs.
  • I was just about to leave the same comment.

    One would think that you would see a little more accuracy from the Discovery Channel.
  • A man jumps off the top of the Empire State Building. As he passes the 18th floor someone leans out the window and asks him:

    "How's it going?"

    To which the faller replies:

    "So far, so good."

  • Re:Speed of sound vs altitude (Score:4)

    by frankie ( 91710 ) on Thursday November 02, 2000 @06:59AM (#656015) Journal
    the speed of sound goes UP as the air pressure goes down.

    Not quite -- due to decreasing air temperature, the speed of sound actually decreases as you go up for a while, then increases again until you hit near-vacuum.

    • Sea level -- 1116 fps
    • 36000 to 82000 feet -- 968 fps
    • 150000 feet -- 1075 fps
    • 250000 feet and up -- by a quirk of physics, 1116 fps again!
    NASA has a nice web tutorial on this topic [nasa.gov]. Greg Roth has a more precise javascript calculator [purdue.edu].

  • Mach 1.5? (Score:3)

    by Guido del Confuso ( 80037 ) on Wednesday November 01, 2000 @08:43PM (#656016)
    Wow, that's fast... I was under the impression that breaking the sound barrier was rather stressful for whatever does it, since the sound waves it creates can't get out of its way before it plows into them. I guess a lone parachuter may not be making much sound, especially until she hits the atmosphere, but once she does reach air it seems to me that the amount of drag on her body would amplify greatly due to the high speeds and the effect of the sound barrier. If the sound barrier can tear the wings off of airplanes, I wonder how she plans to prevent, say, her head from being torn from her neck?

    Of course, I Am Not A Physicist, so please don't flame me if I sound stupid. =-)
  • *ahem*. PRESSURE SUIT = INSULATION.
    Also, temperature at altitude will be around
    -70, but in very thin air... so heat won't conduct away that fast.
  • And remember, at the altitude she'll be breaking mach at, the air will be so thin it won't be noticable (or barely). There will be no 'shock wave' to push through (at least, none that poses a problem). Breaking mach at lower altitudes won't happen easily.... not enough force to overcome resistance( terminal velocity drops with density)
  • have you considered that the speed of sound has nolthing to do with air density and everything to do with temperature?
    The speed of sound in the thin, but warmer air very high up is similar to that on ground.

    The speed of sound in COLD air is slower, and in WARM air is higher.
  • Not big at all. Byt the time she reaches ground, she'll be going SLOWER than the average skydiver, due to increased bulkiness of pressure suit.
  • If htere is no air up there for her to use to 'contorl' a spin, how would there be enough air to cause one in the first place?
  • The standard rule of thumb for freefall is 7 seconds/1k feet. It takes 10 seconds to reach terminal (120mph when flying belly down). 7 seconds for each additional thousand feet.

    Head down is much faster. My normal belly down (Relative work) speed is around 112 MPH (I have a protrack [prodytter.com] which records my speed). My head down speed is 168MPH so far, I'm still working on head down stability.

    A belly down jump from 13.5k feet, dumping at 3k is a little over a minute of free fall.

    At the super high altitude with less air resistance you fall MUCH faster and the speed of sound is slower. She will probably fall with a drogue chute attached to slow her down a bit. Getting a pre-mature deployment at higher than normal speeds will kill her.

    Yes, I am a licensed skydiver (USPA [uspa.org] #153704, A-34316). I have 100 jumps, working on my C license now :)

    -Shishak

    "Now, I hope and pray that I will, but, today I am still just a bill"

  • Altitude, altitude, altitude.
    She will not be breaking mach or anywhere NEAR mach at 10,000 feet. As the article said (and you quoted), at those altitudes, she will be basically like any other skydiver, though a bit slower due to bulk of pressure suit.

    At high altitudes (100,000 feet or so), she WILL break mach, but the air is so thin.. well.. tha'ts why she can do it! The X-1 didn't go that high.
  • It was in the late 50's for a a test called Project Manhigh

    i thought hippies started that program in the 60's...

    ---

  • Yeah.. cause the plane was forced through very high speeds at low altitude. At extreme altitudes (100,000 feet is WAY over any commercial jet, even Concorde, or even supersonic fighters, or bombers, etc...), there is basically very little air resistance.

    Keep in mind, it takes energy to produce heat; if she was encountering enough friction to burn up in freefall, she would SLOW DOWN, not burn up. She would slow unless something was forcing her faster.....

    The reason orbital objects burn up is due to horizontal velocity.
  • Seems like there's not much left to do after something like this. I suppose some nuts will try to set a new record by having sex while they jump from 31 mi. up.

    Yes, but then what will they do for the other 63 seconds?
  • We're all under the illusion that there is a such thing as perpetual freefall.

    There is; that's what being in orbit is.

    Cheers,

    Tim
  • WHAT sonic boom? There's basically no air up there! She'll be fine. Going mach 1.5 at lower altitudes is bad, but at those altitudes it's ok. Same goes for the heat: mach 1.5 is not nearly fast enough.

  • Re:Mach 1.5? (Score:3)

    by HeghmoH ( 13204 ) on Wednesday November 01, 2000 @08:48PM (#656045) Homepage Journal
    It's really simple. Way up, no air, she can go fast with no trouble. As she gets lower, there's more air. More air means more drag. Once that drag exceeds the force of gravity, she'll start to slow down, producing less drag. So her drag will never significantly exceed enough to counteract gravity.

  • She's not breaking the sound barrier in thin air. (Score:3)

    by tjwhaynes ( 114792 ) on Thursday November 02, 2000 @07:14AM (#656050)

    Wow, that's fast... I was under the impression that breaking the sound barrier was rather stressful for whatever does it, since the sound waves it creates can't get out of its way before it plows into them. I guess a lone parachuter may not be making much sound, especially until she hits the atmosphere, but once she does reach air it seems to me that the amount of drag on her body would amplify greatly due to the high speeds and the effect of the sound barrier.

    The speed Mach 1.5 is a little misleading - in the air she'll be travelling through, she won't be breaking the speed of sound, although she may reach around 1000 miles/hour. In thin air, the speed of sound is much higher than at sea level. She will actually decelerate as she falls into the thicker lower atmosphere, so at no time will she be going fast than the speed of sound in the air she is travelling through. The main danger as far as I can see is difficulty in preventing a spin in a thin atmosphere - there is little air resistance to allow you to stop rotation motion. Still, for an experienced sky diver, this shouldn't be an insurmountable problem.

    Cheers,

    Toby Haynes

  • She will have no control so why is she training? Maybe to have more time before she craters. Will her frag count go down if she does? Taking bets on how big the hole will be.

  • R2, are you sure this thing is safe?

  • No, she won't. The space shuttle experiences large amounts of friction because it is also moving at very very high horizontal speeds (an orbital velocity) as well as vertical. If it fell from a stationary position, silica tiles probably wouldn't be needed.

    She'll be going Mach 1.5, but there's little air resistance, so there won't be much friction or heat. There will only be as much air resistance as her mass times the force of gravity. So evena t Mach 1.5, she own't experience more friction than someone at terminal velocity 10,000 feet up.

  • As a side note, before they actually flew that brave volunteer, the Air Force--I dunno if NASA was around then--pitched dummies in pressure suits out the balloons. Some people speculate that witnesses finding the dummies on the ground led to a lot of the alien crash stories. I think they were doing this from the late forties to the early fifties. The project was called "Man High" and there's a History Channel documentary on it. Way cool footage on that show. There's also a web page somewhere. Try searching for "Man High" on google. You'll have to wade through lots of gay porn hits to get to it, but thats the nature of search engines.

  • Even stranger... (Score:5)

    by hugg ( 22953 ) on Wednesday November 01, 2000 @08:50PM (#656073)
    You think that's wacky? In the early 60's, there were a number of designs for a single-person bailout device, for "bailing out" from *orbit*. MOOSE [friends-partners.org] was one such design, where the astronaut was enclosed in a foam shield.

    Mach 1.5, bah! Try Mach *25*! :)

  • Single human woman (Score:3)

    by booch ( 4157 ) <slashdot2010@cra ... m ['k.c' in gap]> on Thursday November 02, 2000 @07:43AM (#656074) Homepage
    It will generate a much much more powerful shockwave which it will then have to overcome once it approaches the speed of sound. A single human woman isn't going to have this problem.

    Why does it matter if she is single or married?

  • Re:Pressure suit? Reentry heat tiles? (Score:3)

    by seanson22 ( 202693 ) on Wednesday November 01, 2000 @08:52PM (#656080)
    This is a good example of where it pays to read the linked article. In this case the article mentions that burnup on re-entry is caused by the speeds necessary for orbit. With entry of asteroids it is the speed that got them to earth that is the problem. Since she will be starting at a stable speed relative to the earth, and her only speed will be that due to gravity, she won't have any real friction/heat problems.
  • The good thing about having insanely rich folk around is that sometimes they really aren't that bright, and provide us slaves with high-quality entertainment on how to thin the herd (evolution in action).

    Methinks I smell a candidate for the Darwin Awards if things go south for winter...
  • The longest delayed skydive was made by Capt. Joseph W. Kittinger, who dropped 25,820 m. (84,700 ft.) from a balloon at Tularosa, New Mexico, USA, on August 16, 1960. He fell for 4 min. 37 sec. before his parachute was deployed automatically. In Kittinger Park in Orlando Florida the sign says that PLUS that he hit mach 1 BREIFLY while falling. IF this woman plans to jump from TWICE as far up.. shouldnt that mean a 8 min freefall? That I would love to do.
  • Article says something about not enough air up there to control attitude - she'll start spinning or tumbling and the rotation will make her black out. If she's tumbling long enough it might cause problems. I'd imagine they'd use a altitude controlled chute and maybe some kind of drouge to try and stop any spinning in case she is blacked out but you can just imagine her unconcious, spinning, through 10,000 feet and her chute tries to open and gets twisted up and she keeps dropping. Not a pretty sight.
  • Cheryl is neither rich, nor insane. She is one hell of a skydiver, though, and able to beat most men at their own game. She'll do just fine on this, as she has on everything else she's tried.

    She'd 0wn your ass, d00d... take it from me, I know her.

    ---

  • Re:Pressure suit? Reentry heat tiles? (Score:3)

    by mmontour ( 2208 ) <mail@mmontour.net> on Wednesday November 01, 2000 @08:56PM (#656107)
    Re-entry friction is less of a problem if you drop straight down. Something in orbit has a very large horizontal velocity (too lazy to work out the numbers, but roughly the circumference of the earth in 90 minutes), and much of the heat of re-entry is caused by this horizontal velocity.

    According to the article she'll only get up to Mach 1.5 [doesn't say if that's relative to the speed of sound at sea level, or to the actual speed of sound in the air she's passing through], and that's quite a bit less then orbital velocity.
  • While the dialogue and acting were dreadful and elementary science was so obviously ignored that it was painful to watch, the movie did have some nice touches.

    In particular, the Martian landscapes were done very prettily and not horribly wrong, and the effects overall were quite reasonable apart from a few embarrassing moments during the sand tornado and during alleged "weightlessness".

    If you survived cringing throughout the dreadful dialogues and didn't care much about storylines or basic physics then it was watchable. Almost. :-)

    I hear that a lot of the problems were due to a change of director or producer or something part-way through. The politics probably pissed off all the actors and other staff, and the end result was amateurish without the benefits of B-movie chuckle value.
  • Actually, following a link from a poster up above to here [pbs.org], they say he landed 14 minutes later. Holy shit. Can that be right?

    Jason
  • You need to start thinking about Oxygen at about 10,000 to 12,000 ft, the FAR's require O2 to be used when cabin presure goes above 12,500 ft (simplification actualy) for small aircraft. At about 25,000ft the partial pressure of the O2 in your lungs goes bellow the pressure of the blood that is supposed to be absorbing it. you will pass out rather quicly at this altitude.

    The full rules says that pilots have to use 02 when over 12,500 for more than 30 min or over 14,000 ft at all. It would probably be smart to use it from about 8,000 to 10,000 ft up.

    The Cure of the ills of Democracy is more Democracy.

  • >All you need to know to find speed of sound is the static temperature of the air.

    So you are saying that speed of sound is not influenced by altitude? Of course, as altitude increases, temperature would tend to decrease... but the posters above said something about the density of air at different altitudes having an affect on the speed at which sound waves travel at a given altitude.

    I guess the question is this: If the concorde travels at speeds greater than Mach 2 and the SR-71 > Mach 4, is the SR-71 actually more than twice as fast as the concorde because it operates at much higher altitudes?

  • Question... (Score:3)

    by Temporal ( 96070 ) on Wednesday November 01, 2000 @09:11PM (#656140) Journal
    How, exactly, does one get a balloon to float outside of the Earth's atmosphere?

    ------

  • Speed and heat generation. (Score:3)

    by Christopher Thomas ( 11717 ) on Wednesday November 01, 2000 @09:15PM (#656142)
    Re-entry friction is less of a problem if you drop straight down. Something in orbit has a very large horizontal velocity (too lazy to work out the numbers, but roughly the circumference of the earth in 90 minutes), and much of the heat of re-entry is caused by this horizontal velocity.

    Orbital velocity is about 8 km/second (5 miles/second).

    Energy shed into the atmosphere is roughly proprortional to the cube of the velocity, so something travelling at Mach 1.5 (about 0.5 km/second) sheds about 4000 times less energy per unit time (and generates 4000 times less heat).

    Summary: Quite a bit slower, and *much* less heat generation.
  • 1)Wouldn't slowing her down from Mach 1.5 to 0 with the use of a parachute tear this woman in half?

    Something like zoom zoom zoom zoom ripcord *flap* *SPLUTCH*

    2) If she blacks out, how deep a crater is she going to leave in the Earth when she hits it? I think she should be parachuted out over a graveyard so that if she messes something up, at least noone'll have to incur the cost of burying her, just slap a tombstone over the 100' wormhole her corpse'll make slamming into the ground.

  • Human versus jet aircraft (Score:4)

    by PhloppyPhallus ( 250291 ) on Wednesday November 01, 2000 @09:02PM (#656149)
    The problem here isn't so much traveling at Mach 1.5 (I'm sure the pressure suit is well insulated and heat resitant to avoid the cold and the heat) but its the point where she breaks the sound barrier. After that, it should be smooth sailing, since she's passed her own shockwave. However, I still do not belive this will be a considerable problem. remeber, an airplane is many many times more massive than a human being. It will generate a much much more powerful shockwave which it will then have to overcome once it approaches the speed of sound. A single human woman isn't going to have this problem. In addition, remeber, surface area for objects is typically a in a higher ratio to mass for less massive objects (i.e humans) than massive objects (i.e. jet aircraft). For a simple experiment in this, throw an ant, a cat, yourself, and a horse down a 100ft mine shaft. The ant is going to hit the ground with little to no damage. The cat may break a leg or too, but will live. You will more likely than not die. The horse will splatter. Same thing applies to the drag forces about the fusalage of a plane and about this woman. Its going to be relatively much less for the woman.
  • The last one was damn close to free falling. The guy, who's name escapes me at the moment, used what is referred to as a "drogue chute" to help maintain stability during the fall. It's not as if he were coming down with wings or a jet pack.

  • Re:Holy Cow! (Score:3)

    by AntiNorm ( 155641 ) on Wednesday November 01, 2000 @09:16PM (#656154)
    Surely there's someone here who can give us an estimate of how long it would take?

    The previous world record was 102800 feet, set by Captain Joseph Kittinger in 1960. IIRC, he freefell for between four and four-and-a-half minutes, and pulled at an unusually high altitude (20000' or thereabouts). So it follows that a freefall from 160000' would probably take in the neighborhood of 7-8 minutes.

    Yes, I am a skydiver.

    =================================
  • A similar jump [af.mil] was done in 1960 by the Air Force. Project Excelsior [af.mil] was a pre-NASA experiment to see if it was possible for pilots and astronauts to eject from these kinds of altitudes (102,800 feet to be exact, which took 4 minutes and 36 seconds). They solved the spinning problem by deploying a small stabilizing chute first to slow him down. This site [exn.ca] says Captain Kittinger almost died on the first attempt when the stabilizing chute tangled and he blacked out. Luckily, the main chute was set to deploy automatically. Apparently his landing words of wisdom were "Thank you, God, thank you."

  • Go Cheryl! (Score:5)

    by mjh ( 57755 ) <(moc.nalcnroh) (ta) (kram)> on Wednesday November 01, 2000 @09:23PM (#656157) Homepage Journal
    I have almost 1000 skydives. Speaking for the skydivers, I can't imagine a single one of us who wouldn't absolutely love to have the oppurtunity to train for, and make this jump.

    We're all under the illusion that there is a such thing as perpetual freefall. 31 miles up! That's going to add some freefall time to your log book! Let's see. My charts stop at 15k feet. Assuming you open at 2500 ft, that's somewhere around 75 seconds of freefall, through approximately 2.5 miles of very thick air. I wonder how long this jump will last?

    I'm sure that the danger that they refer to is related to the thinness of the air. Without air blowing by you, you can't control which way your body is turning. If you can't control that, then you can't prevent a spin. That would be bad.

    BTW, Cheryl Stearns is among the elite skygods. She's got a gazillion jumps, and a bunch of style and accuracy championships. She's been a fabulous ambassador to the sport, and should rightfully be credited as one of the sport's most important participants. [makeithappen.com]

  • I know that the skydiver isn't going to need ceramic tiles like the space shuttle. But, there will be some heat produced during the fall. Think of it this way: a 100Kg body is at 165,000 feet above sea level. It contains a large amount of potential energy due to the height. Almost all of that potential energy has to be dissipated away as heat before the body comes to rest at the ground. Can anybody who still remembers their basic physics compute the amount of heat that should be produced? How much of it will end up in the skydiver? I guess a lot of the heat will end up in the air you are falling thru, so this probably isn't a big deal. But I bet the amount of heat involved would incinerate you if you weren't being air-cooled by a 100mph wind for most of the fall.
  • OF course you are correct... but...

    It's all about air density.
    It's easy to hit speeds over mach during freefall at such high altitude because there is almost no air resistance. Yes, an f-15 achieve 2.5M, but has thermal issues (as does concorde, etc). That' sbecause of the realatively low altitude they work at. (A concorde cannot do Mach speeds anywhere near sea level either, it must be at around 50,000 feet.)

    Given that only G is driving her downwards, she will slow down, not heat up, when encountering ever-thickening atmosphere.
  • One standing on a platform accelerating at 1G could not tell the difference between acceleration, or standing in a 1G field.

  • What's left after this? (Score:4)

    by Art Tatum ( 6890 ) on Wednesday November 01, 2000 @09:09PM (#656167)
    Seems like there's not much left to do after something like this. I suppose some nuts will try to set a new record by having sex while they jump from 31 mi. up.
  • It has been done before. It was performed by NASA to test a pressure suit. The guy who did it had a leak as well in the suit, so when he jump part of his body actually froze and he experienced decompression. It was a Guinness Book of World Record jump and the story is found here [guinnessworldrecords.com]. Oddly, he did reach over mach 1, but he couldn't tell how fast he was going at all. If I could do it, I would.

    Even the samurai
    have teddy bears,
    and even the teddy bears

  • Rough calculation is here:

    50000(m) = 1/2 * 9.8(m/s^2) * t^2
    100000(m) = 9.8(m/s^2) * t^2
    10000(s^2) = t^2
    t = 100 seconds

    So, a free fall from 31 miles without any air friction will crash you into the land in a little less than 2 minutes.

    Air friction resulting from her stationary body, any skydiving trick movements and parachute counted in, I'd give an estimate of 15 - 20 minutes at most...while a typical game of mahjong takes quite a bit more time...

    I guess a game of Dominoes or Dopewars should be more like it...
  • Upsidaisium.
  • 10) Could possibly run into the Mir spacestation
    9) Only source of hot air big enough to get baloon that high is the new Holoween Document
    8) Appearing on Fox's Scariest Baloon jumps
    7) Who wants to be the showoff of skydivers?
    6) I'd get bored, need to be around shiny objects
    5) Training would leave very little time to post Top 10 lists on slashdot
    4) What if you have to use the bathroom in the middle of the jump?
    3) When was the last time you saw a skydiver on TRL?
    2) The pressure suit makes you look fat
    1) Hitting the ground

  • What can go spectacularly wrong (Score:3)

    by Thagg ( 9904 ) <thadbeier@gmail.com> on Wednesday November 01, 2000 @11:02PM (#656178) Journal
    The Soviets, like the Americans, did similar extremely-high-altitude balloon flights with people jumping for recovery. They didn't use drogue chutes for stabilization, though; at least not at first.

    They started spinning so fast that they broke apart. The air is so thin that there's no damping whatsoever.

    thad

Slashdot Top Deals

What is research but a blind date with knowledge? -- Will Harvey

Close