Have you seen this one? High altitude balloons replace satellites...
Replies to This Discussion
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Permalink Reply by Steve Spicklemire on -
I find it interesting that they use hydrogen. I know it probably has significantly better lift per liter of balloon volume, but would it be worth the safety risks? Is it much cheaper than helium?
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Permalink Reply by Jason Krueger on -
Hydrogen is slightly cheaper than Helium. StratoStar and Taylor have been using hydrogen for non-PR launches. When we have press and people from the public at launch and see a hydrogen tank we have to answer many questions. The lift is not significant (only through observation). It is worth looking into, but you will need a different regulator which fits the Hydrogen tank.
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Permalink Reply by Howard Brooks on -
Steve,
Many of the Amateur Radio High Altitude Balloon (ARHAB) groups have flown hydrogen. The extra lift is not that much, since the lift comes from the difference of the fill gas compared to the normal atmosphere.
A great program for doing lift calculations, that includes fill volume of the gas, burst altitude of the balloon, and ascent rate has been written by Hank Riley, N1LTV. The program was written in BASIC and has been adapted to Windows. (I don't know of a program for the Mac.) Here's the link: http://www.geocities.com/n1ltv/newliftwin.htm
I'd also recommend joining some of the Yahoo groups on high altitude ballooning. Personally, I am part of GPSL (Great Plains Superlaunch), BALLOONING (sponsored by the Arizona Near Space Research program), and Balloon_Sked (a great place to follow balloon launches). The GPSL and BALLOONING groups have had several discussions on using hydrogren to fly, simply for the lower cost per tank. Hydrogen is about one-third the cost of helium for a tank. With caution, and I'd always use a regulator, I don't see any problem with hydrogen. (Although I haven't done my own flight, yet.)
I do agree with Jason about only using it on private flights. When I fly with a school group or the Scouts, I'd still use helium.
Howard
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Permalink Reply by Steve Spicklemire on
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That makes sense. I guess the difference in density between molecular hydrogen (2g/mol) and helium (4g/mol) when compared to air (29g/mol) is not so great after all... so the rough lift is (best case) 25 g/mol for helium and 27 g/mol for hydrogen... roughly speaking? Is there no real concern about safety? I guess the Hindenburg was a special case. ;-)
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Permalink Reply by Steve Spicklemire on
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Great links Howard. Thanks!
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Permalink Reply by Howard Brooks on
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Here is a good link to a government document on hydrogen safety.
http://www.depweb.state.pa.us/deepminesafety/lib/deepminesafety/tra...
Slow filling of the balloon in the open air should not be a problem.
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