Ballooning into Space

flyboy writes: "Two ballooners are going to attempt to get to 132,000 feet in a helium balloon named QinetiQ1. They are going to do this wearing spacesuits and sit in what looks like armchairs in an open gondola. From that altitude the sky is black and you look down on whole countries in one go. It looks like they might actually do it as well, since they have some serious backing, they are sponsored and supported by the former DERA, who have lots of experience in all things aeronautic."

Comments

It may not be just a joy ride...

[jdrogers]

I wouldn't discount this as a hairbrain idea from some thrill seekers. If you look at the cost of launching any payloads to that altitude, it makes the cost of specialized ballons look a lot better. I'm not sure what the use of getting people up there is, but as stated in the post, there isn't much atmosphere above you and hence not much turbulance, so things like short, month-long telescope missions and other scientific observation could be done much cheaper.

If I can dig up some links I've seen about this, I'll post.

Cheers,
JD

Use this as a launch vehicle???

[burtonator]

OK. Just some crazy thinking...

Did you guys see this picture:

http://www.qinetiq1.com/gfx/large_balloon.jpg

That is a HUGE balloon!

Now here is my thinking...

Remember the Hindenburg? (sp?)

What if this actually worked and on the next attempt they fill the balloon with Hydrogen?

If they built a special gandola which was a SMALL spacecraft, they could use the hydrogen from the balloon as fuel and possible exit the earths orbit.

Would this work? I don't have access to any of the math behind this so someone with experience could help.

... and we all know that everyone on Slashdot is a Rocket Scientist!

Only half way to space.

[AJWM]

Nice, but 132000 feet is only 25 miles, just half of what USAF awards astronaut wings for (50 miles, and some X-15 pilots earned them). Even less than half of the 100 km that the International Aeronautical Federation considers the edge of space.

Still, it sounds like a fun ride!

132,000ft and then what?

[psych031337]

This does not really strike me as a major aeronautical achievement.

Col. Kittinger did a 102,800ft rise in a balloon back in the early 60s (Project "Man high"). The thing that makes this ballon trip unforgettable to history (at least for me and at least until somebody pushes the limit) is the fact that he opened up the gondola he was hanging in to throw himself out into the hands of gravity for 18 1/2 miles.

You can read up on it here and here

Re:Weightless or not?

[CaptainCarrot]

Y'know, this is high school physics. (Or ought to be; it was when I was a teenager.) You never float about because of a "lack of gravity." Similarly, you don't really need gravity to plant your feet firmly on the ground. What you need is acceleration. The force that supplies this acceleration is irrelevant to the effect. In the neighborhood of a massive body like the Earth, the force of gravity provides it. On orbit, an astronaut floats around not because there's no gravity -- there obviously is; that's why his spacecraft is orbiting instead of flying away -- but because his entire frame of reference, including the floor he would otherwise be standing on, is being accelerated at the same rate towards the center of the Earth. The craft remains in orbit instead of falling because it begins with enough "horizontal" velocity to "miss" the earth by the radius of the orbit, to put it in the simplest possible terms. Orbits decay when something acts on the "horizontal" velocity to decrease it. That's why the best way to achieve re-entry isn't to aim your vehicle at the earth, but to slow it down. Eventually, it slows down enough so that it no longer "misses". Vehicles in low orbits can have their orbits decay from the very small amount of air resistance due to the tenuous upper atmosphere they're within. Lacking air resistance or some other kind of force to slow it down, a vehicle can stay in orbit indefinitely.

Horizontal is in quotes above because it's not quite the right word. More properly, it's a velocity vector normal (or perpendicular) to the acceleration vector. Since the direction of the acceleration vector keeps changing as the position of the vehicle changes, the velocity vector keeps changing too -- as it must; there's an acceleration acting on it. The equations to compute the initial velocity needed to keep a vehicle in orbit at a particular altitude are not complex.

This is exactly the same physics that keeps the Earth orbiting the Sun and the Moon orbiting the Earth, just on a smaller scale.

The writers of Star Trek never understood how this worked. In TOS there were a number of episodes where the engines had been damaged or sabotaged and the orbit was somehow rapidly decaying. Only a moron would have put them into such a low orbit that it needed constant thrust from the engines to maintain it in the first place.

"Weightlessness" is also achievable by falling at the same acceleration imposed by the force of gravity. For the Earth, that's about 9.8 m/sec^2. Astronauts train at weightlessness for brief periods by doing just that -- they get into a specially modified cargo plane, fly up as high as it will go, then pull into a steep dive. They float around inside the plane just as they would on orbit for as long as the dive lasts.

The balloon will never be travelling anywhere near fast enought for any of this to occur.

Re:How long would it take to get back to the groun

[psych031337]

They need some sort of board to lay on that will keep them from flipping around while falling.

This could be done with a small stabilizing chute. It was used in the legendary Kittinger jump (Project Excelsior). This guy was jumping from 19 1/2 miles up, and 16seconds from jump time a small stabilizer chute would automatically open to stop spinning. Tests with Dummys back then have shown that an aerodynamically unstable object like a human can easily hit 200rpm in free fall. 140rpm for a minute are considered fatal.

Oh, and if you are tired, remember it will be short nap - 19 miles are crossed in less than 14 minutes.