Homemade spacecraft reaches 100,000 ft, films the whole way | Hacker News Reader

Homemade spacecraft reaches 100,000 ft, films the whole way

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136 pointsggasp23 comments

If you plan on duplication read this:

http://www.eoss.org/pubs/faqloon.htm

and please pay special attention to the 'notice for airmen'.

I'd hate to be on board a plane colliding with this, and even if the chances are small the outcome could be bad enough that I think that a toll free phone call is not too much to ask.

Great experiment otherwise!

At an altitude of 100,000 ft (30.48 km), the balloon reached the stratosphere portion of our atmosphere. The space shuttle and other spaceships reach the thermosphere, which is the layer between 95km and 600km. The space station orbits at an altitude of 350km. The edge of space, called the Karman line, is 100km above the Earth, meaning that the ballon technically did not enter "space". Regardless, this experiment and it's footage are fantastic.

More info at Wikipedia: http://en.wikipedia.org/wiki/Atmosphere_of_Earth

In addition to altitude, another important distinction is velocity. You need to be moving at around 7.5 km/sec (17,000mph) to stay in LEO. Ballons aren't going to help much there. And any orbital spacecraft is going to need some serious shielding if you want it to come back in one piece. Some of the pictures of this Soyuz landing give an idea of the engineering needed: http://cryptome.org/info/soyuz-tma18/soyuz-tma18.htm

The pictures and video are pretty, but calling it a spacecraft is exaggeration. You can't see the curvature of the earth at that altitude. It only appears that way because of the wide angle lens.

I hate to rain on this parade, because high altitude balloons are really cool. They're just not spacecraft and I can't stand exaggerated titles.

Nobody is trying to do science here, that's one very cool dad and as far as his son is concerned it might as well be space.

Petty bickering over definitions doesn't matter much, after all no balloon could take you to the 100Km mark simply because they'd explode long before you got there (as did this one), but 30Km is three times as high as your typical passenger jet will fly and that's good enough for most people.

The article about the Karman line literally reads:

"Some people (including the FAI in some of their publications) also use the expression "edge of space" to refer to a region below the conventional 100 km boundary to space, which is often meant to include substantially lower regions as well. Thus, certain balloon or airplane flights might be described as "reaching the edge of space". In such statements, "reaching the edge of space" merely refers to going higher than average aeronautical vehicles commonly would.[5][6]"

http://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line

There's a distinction (which admittedly might only be in my head) that a balloon _requires atmosphere_ to work, which means it can't get into _space_, since buoyancy in the surrounding air runs out by the time you get to "space" where there _is_ no "surrounding air".

'course that's no more a technical definition of "space" than "100km" or "the Karman line"...

Still, that's a cool project!

Well, that depends on what you mean by 'work', if with work you mean go up for ever then the answer is a clear 'no'.

However the 'envelope' for just about any balloon that is not built with extreme altitude in mind lies within rather than on top of the atmosphere.

A balloon will go up until the pull of gravity is balanced by the lift, and in most balloons that point will not be reached until the balloon bursts from a lack of counter-pressure by the atmosphere.

Why should they burst? Certainly a little rubber balloon will - but the difference between a good helium balloon and vacuum isn't much - a thin foil layer would contain it without bursting.

The bursting is a fairly good automatic cut-down. If it doesn't burst, it will ceiling at some point, and then zoom around until something happens.

You might get some more height with a stronger balloon (or a larger balloon with less gas) but you want the flight to be over in a reasonable time if you ever want to get the payload back.

So then you have to use nichrome wire or something as a cutdown, just something else to worry about. 100k-ft is pretty good.

Perhaps it is natural for an engineer to get irked when the press describes a thousand dollars worth of latex and helium, which only did 30km, and had no orbital velocity at all, as a "spacecraft".

It was a "spacecraft" in the same way a cameraphone is a "workstation", or BASIC is a production language.

Somehow I doubt this is the last rocket, balloon, or other high altitude vehicle they will be building, too.

Amusingly, helium is a fossil gas. (It's extracted from the top of natural gas reservoirs.) Once we run out, there won't be any more, and the only way to make more is through nuclear transmutation, or extraterrestrial mining. No matter how you look at it, filling balloons with helium and giving them to children is going to be too expensive in the near-ish future.

Also, attaching an iPhone to a weather balloon seems like an expensive and roundabout method to destroy a phone, if the parachute fails, or if it hits water hard enough to break the seal on the instrumentation capsule.

The iPhone never left the ground; they used it to receive the GPS signal from the balloon.

If you listen to the audio track of the video there clearly is the tell-tale chirp of a cell phone connecting in there.

Hydrogen is lighter than helium and will always be cheap and plentiful. Helium does have the advantage of being inert.

They make it look so easy. I bet many parents would be willing to buy such a kit. Does anyone sell this yet?

Someone mentioned that you need to notify the FAA and such before doing something like this. I think the regulation surrounding this would make it hard for most parents to do even with a simple kit.

On the other hand, I used to love playing with Estes Rockets(http://www.estesrockets.com/) as a kid (Which I still am since I still love those things ;p) . Those don't go far enough to be an issue.

IIRC launching a weather balloon is regulated differently than launching a rocket that will enter/cross regulated air space. Still, you're going to get into a huge load of shit if you get caught without getting prior approval.

Don't people worry about where these things land? That's pretty fast to be landing on someones head!

Or on a highway.

If they actually strapped an iPhone into the capsule, then it would have been interesting to capture accelerometer data too.

FWIW - sounds like they did use an iPhone:

"We used the instatracker app. You can use buddyway as well but we found it unreliable and too complex. A friend lent us her old 3G with a cracked screen."

Coolest Dad ever!

Somewhat related, one wish of mine is to be lifted by a balloon to the degree that I can still walk and run, but I can also jump 20 feet if needed.

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