World Record Sky Dive

[outdoor_lover]

Did anyone else get a chance to watch this live today. It was incredible and breathtaking. That takes alot of guts and I'm sure his adrenalin levels are still not normal at this hour...WOW!

https://www.youtube.com/watch?v=q4Z7M4bPfHk

[rwstorm]

Oh, I watched it and loved it. In fact after the attempt last Tuesday was called off and they planned another try today, I bailed on a planned hike in the Organ Mountains by Las Cruces to be sure to be home to watch it live. Being as I spent a career launching weather balloons carrying radiosondes aloft to burst altitudes similar (at times) to where this thing went, it was so very cool to finally see what it looked like from up there looking back at earth! Plus having launched those balloons for more than 3 years at fairly nearby Midland and having visited Roswell on many occasions made it even more heavy for me. Guts indeed...way to go Felix! Awesome!!

[outdoor_lover]

@RWStorm
That's really cool Randy. It's always more interesting when you have had experience in that sort of field as well. I have been to Roswell, and I totally understand why they would pick that site, although I'm sure all of those Pronghorn probably didn't care for the invasion of people and vehicles.....

[Alston_Neal]

833 MPH.....WoW!
That's just slightly faster than the Cannondale Kid drives.


Way to go Felix!

[SkyIslander18]

"the first human to break the sound barrier with just his body"

How cool would that be to put on a resume!

[joebartels]

"the first human to break the sound barrier with just his body"

How cool would that be to put on a resume!

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[autumnstars]

Pretty crazy, no doubt.

Given the cost of pulling something like this off...
Well, let's just say Red Bull is really helping push the limits of extreme sports (and other antics) by being willing to sponsor these types of things that other companies wouldn't touch with a 10-ft pole.

[paulhubbard]

"the first human to break the sound barrier with just his body"

Yeah, that's cool land all, but I have been "caller number 9."

I wonder how warm he got from the air friction created by traveling that fast?

[outdoor_lover]

I wonder how warm he got from the air friction created by traveling that fast?

I wondered that too. There's a point where you enter the Earth's atmosphere where s*** catches fire and burns up. I mean they had to have special tiles on the Shuttle to protect from the heat. So was he still lower than that point? He certainly looks like he was above the actual atmosphere to me.....

[chumley]

He jumped from about 24 miles up. The space shuttle orbits about 10x higher than that. If it helps, if you recall watching a space shuttle launch, the booster rockets were jettisoned at about the point he jumped from, about 2 minutes into flight!

I did see that the suit he was wearing had all kinds of sensors in it and how it was affected by the journey is now being studied in order to improve future space suits.

[outdoor_lover]

@chumley
I had heard mention that NASA was really going to take a big look at this, with the future scenario in mind of Astronauts having to bail from further up.....

[nonot]

I wonder how warm he got from the air friction created by traveling that fast?

I wondered that too. There's a point where you enter the Earth's atmosphere where s*** catches fire and burns up. I mean they had to have special tiles on the Shuttle to protect from the heat. So was he still lower than that point? He certainly looks like he was above the actual atmosphere to me.....

He only went about mach 1, not mach 20+ where the shuttle hits the atmosphere. Aerodynamic heating only begins around mach 3. The hypersonic ionization that causes plasma heating on the shuttle doesn't start until you get way up above that.

To compare - most aircraft that can break the speed of sound are still mostly made of thin aluminum and plastic/resin composites. The spaceX vehicles don't even use tiles I don't think, because they slow down using the feather to create more drag.

[outdoor_lover]

@nonot
So, what you're saying is that it really doesn't have so much to do with entering the atmosphere, but more about speed itself??? Sorry, I'm way out of my element here, never took physics....

[nonot]

It takes both.

Speed+no atmosphere = no heat (lots of things hurl through space really fast without burning up)
Atmosphere+no speed = no heat (we aren't getting hot due to the air when we walk around. The skyfall, though it seems fast, still falls into this category.)
Atmosphere + speed = fireball/heat (meteorites/shooting stars, the shuttle. It takes a lot of speed to fall into this category, much more than mach 1.)

[CannondaleKid]

Well, let's just say Red Bull is really helping push the limits of extreme sports (and other antics) by being willing to sponsor these types of things that other companies wouldn't touch with a 10-ft pole.

I wouldn't waste my $$ on a Red Bull but it seems there are enough who do that Red Bull makes enough money they can afford to.

BTW, I thought Red Bull gives you wings... I suppose they wouldn't fit inside the capsule with Felix.

[Alston_Neal]

What about terminal velocity, how was he able to exceed it?
For a cat it's 60 mph, don't ask me why I know this.
But a human...around 200?

[outdoor_lover]

@nonot
Great Explanation. So if I get it, it's all about friction. But since air/atmosphere itself doesn't have the ability to produce much friction on it's own, you need some incredible speeds to create enough friction moving through the air, to create actual heat, in this case, alot of heat....

So is that the case just for the Upper Atmosphere? Or just any good old air. If a Jet did Mach 20+ at 5000 feet, would it burn up???

[chumley]

If a Jet did Mach 20+ at 5000 feet, would it burn up???

It might break apart long before it got there.

One of things I recall reading after 9/11 was that the 2nd plane to hit the twin towers did so traveling at 500+ mph. Aircraft engineers were stunned that the Boeing 767 involved actually managed to stay in one piece at that speed and hit the building. While it is made to cruise at 600mph at an altitude of 30,000-40,000ft, the higher air pressure at lower altitudes requires it to travel more slowly. Higher speed plus higher pressure can cause the control surfaces on a plane to literally snap off! It's one of the reasons why takeoff and landing are the most dangerous parts of flight. The stresses on the aircraft are highest.

To make it strong enough to withstand that kind of stress, it would be too heavy to fly!

[nonot]

@nonot
Great Explanation. So if I get it, it's all about friction. But since air/atmosphere itself doesn't have the ability to produce much friction on it's own, you need some incredible speeds to create enough friction moving through the air, to create actual heat, in this case, alot of heat....

So is that the case just for the Upper Atmosphere? Or just any good old air. If a Jet did Mach 20+ at 5000 feet, would it burn up???

Sort of...

Friction plays a role in aerodynamic heating, and starts becoming significant enough at lower mach numbers, perhaps mach 3, with friction increasing as you get faster. Friction of the material moving through the air is responsible for generating heat, but generally you won't get the "fireball" effect you are after through friction alone.

When you get to a certain speed, the dense object moving through the atmosphere smacks into the air molecules so fast that the energy imparted to these air molecules is enough for the molecules to undergo a state change. The molecules absorbing this energy change from a gas to a plasma. Plasmas have a lot of energy (and are thus very hot). The plasma is what the heat tiles are for, as otherwise the plasma would "burn" (disintegrate) less resistant material - e.g. the plasma is what burns up meteorites as they enter the atmosphere.

Now the lower the altitude, the greater the density of the atmosphere - which causes more drag, more ionization, and more friction - which combine to more quickly slow down the object, if it has managed to survive. The physics are the same at high and low altitude, but the effect is more significant at lower altitudes because the amount of air is greater, and thus the forces are larger.

It would be very difficult for a jet to reach that speed at that altitude. If it did, (let's say it ejected from the shuttle during landing.) it would undergo the process of plasma ionization and thus the plasma induced erosion (and drag, to slow it down). So the plane may or may not last long, depending on its composition. The shuttle is essentially a plane without engines, but with special tile skin. A regular old jet would be in trouble, particularly the blades of the engine and the thin aluminum skin. However, if you use a different engine design, such as a scramjet or rocket engine, and a fancier skin, you could theoretically get to these speeds in a fancy scramjet/rocket plane.

Realistically, you would operate your fancy scramjet/rocket plane at higher altitudes to reduce drag, which allows for faster speed with less ionization. Overcoming the drag at 5000 ft would take more energy than higher altitudes and limit your scramjet plane from getting as fast. Plus you don't want to be the pilot of a plane that is quickly disintegrating!

[nonot]

What about terminal velocity, how was he able to exceed it?
For a cat it's 60 mph, don't ask me why I know this.
But a human...around 200?

Terminal velocity is where
drag force on an object = force of gravity

Several things are pretty much out of the skydivers control (let's ignore gravity's change for now), but the skydiver can change two major things:

The density of the air (by jumping higher up), which means you can go faster to reach the same drag force.
The cross sectional area (by falling head first, body vertical, as he did), which also means you can go faster until you reach the same drag force.

and one minor thing:
coefficient of drag (via an expensive suit - not sure that applies here, perhaps just olympic swimmers)

So this skyfall was what took the most advantage of the two things - the highest ever jump (into the lowest density air), and the position of the skydiver as he fell was optimized for breaking the speed record.


Was your test subject cat Schroedinger's cat, by any chance?