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#1 2004-01-10 21:34:30
Re: Hot-air ballons for reduced laucnh costs?
The Canadian team competing for the x-prize http://www.davinciproject.com plans to use the world's biggest hot-air ballon to lift their rocket to 80,000 feet and then go from there. This approch seems to have great potential. I was wondering what everyone's thoughts are on this? Perhaps several ballons could lift a small X-33 type shuttle replacement (attatched to a rocket) to a high altitude and launch it. I'm wondering why NASA isn't trying this now?
Danny------> MontrealRacing.com
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#2 2004-01-10 22:37:44
- Palomar
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- From: USA
- Registered: 2002-05-30
- Posts: 9,734
Re: Hot-air ballons for reduced laucnh costs?
The Canadian team competing for the x-prize http://www.davinciproject.com plans to use the world's biggest hot-air ballon to lift their rocket to 80,000 feet and then go from there. This approch seems to have great potential. I was wondering what everyone's thoughts are on this?
*Wow, that's quite an interesting concept (trying to visualize it...). I don't think it's been brought up previously in these forums.
I hope one of our resident brainiacs will chime in and give an opinion or two (hopefully not TOO high tech, but rather more in line for the "general reader"). Sorry I can't offer some input otherwise, but I am interested in the responses of others. 
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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#3 2004-01-10 22:54:08
- Euler
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- From: Corvallis, OR
- Registered: 2003-02-06
- Posts: 922
Re: Hot-air ballons for reduced laucnh costs?
I know that NASA has done a lot of research with balloons, though I haven?t heard of them trying to launch a rocket from one. It is an interesting idea, though I think that it might be harder to implement with a "real" spacecraft than with the x-prize. This is because the x-prize only requires suborbital flight. A spacecraft capable of orbital flight must carry a lot more fuel than the x-prize equivalent, and will therefore be a lot heavier. An orbital spacecraft would also save only a relatively small portion of the total energy it needs by launching at 80,000 feet.
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#4 2004-01-11 00:28:44
- Mad Grad Student
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- From: Phoenix, Arizona, North Americ
- Registered: 2003-11-09
- Posts: 498
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Re: Hot-air ballons for reduced laucnh costs?
Don't mean to nit-pick, but I believe that the Da Vinci project uses a helium ballon, not a hot-air ballon. Heliums can reach a higher possible altitude than hot-airs can. A rival X-Prize contender, IL Aerospace, is using a Rozeire ballon, sort of a hybrid helium/hot air approach.
Unfortunately, there are several difficulties with using ballons to launch orbital vehicles. First, they have a limited lifting capacity and even a giant ballon like Da Vinci's can only lift a smalll suborbital vehicle. Second, they are a mess to clean up. That is, unless you throw them away every time, but that wouldn't be efficent now, would it. Finally, it would be very difficult to point the craft in the right direction to achieve the desired orbit. Orbits require extensive calculations to pull off, and if the ballon drifted too far from the equator before launch the rocket might not have enough fuel to reach orbit.
But, they're great for suborbital flights. 
A mind is like a parachute- it works best when open.
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