balloons, air launch, at sea launch etc

[cpooley]

Independent of the type of rocket is the launch means question. Some are planning a balloon launch. Surely, the cost of the balloon is to be part of the launch cost for N Prize cost calculation. Including the cost of the helium. Will it be possible to stay within the financial limit? Even if hydrogen is used?

If air launched, the cost of aircraft operation?

Maybe a concise definition of what constitutes a launcher is going to be needed.

For example, a balloon may have to be a part of the launcher if the high altitude is a requirement for the rocket, but a launch at sea might just be a launch location, and such a rocket could take off from a land based launch pad.

Charles Pooley (planning land or sea launch because I presently don't know which is easier to get the license for)

[pauldear]

Hi all,

Just to clarify, a balloon launch platform *definitely* counts as part of the costs. This includes the cost of hydrogen, helium etc. Aircraft launches likewise count towards cost. Most of this is covered in the nitty gritty of the rules, but I'll be happy to clarify any specific questions. Sorry for the short reply - I'm travelling now (and for the next few days), but with intermittent webternet access.

Best,
Paul

[Monroe]

Charles
The good thing about the balloon launch platform is you can recover it! Second we intend to make our hydrogen from scrap alum pistons donated to our team from Quality Engine Exchange here in Austin and some Sodium Hydroxide we will buy bulk for cheap (unless I can find a donor). We make our own zero pressure balloon from .3 mil donated to the team as scrap from the formosa plastics plant near my mom and dad's place so for us the balloon cost time and some cheap lye from the farm store. The rest gets recovered, that's how we do it.

Monroe

Anybody have a problem with that? I mean our whole mission works like that. I don't see how it could be done another way. Our rocket motors use donated AP and Chemicals and we make them ourselves. These chemical's come from a place that would donate them to anyone for the same reason we are not special there. (except I don't know if they could donate outside the U.S. and I need to find out how Paul see's that) We have gotten very creative getting what we need. We will have to set down with Paul and figure out all the gory little details but I believe we are within the spirit of the rules!

[MisterQED]

I'm also planning on a balloon launch, but I will be creating the balloon out of welded cheap plastic available from Home Depot.
http://pagesperso-orange.fr/ballonsolaire/en-index.htm
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10&productId=100651796&N=10000003+90401+527886
Also figured on Hydrogen but was going to purchase it.
The balloon should run under $400 as long as I don't charge for my time.
Again the launcher will be recovered, but the envelope will be a loss.

[pauldear]

Hi Monroe,

Sounds fine to me. It all seems to come under the heading of "creative scrounging". As noted in the rules, it's only a problem if the "donations" are unrealistic (eg, a company "donates" a complete guidance system which they'd normally sell for megabucks).

As always, it's never a bad idea to check (like you did) to make sure things are OK, but your plans sound fine.

Best,
Paul

[rick m]

MisterQED,

Way back in high school (1969) we made them with a clear top and black sides & bottoms. From pictures I've seem before and the web site you sent, I can't see why all black would be better as the top heats up and the hot air rises above the balloon making that air less dense and prevents the light from passing into the balloon unless the sun angle is low (morning launch?). I've never done any testing to see if this is true but it made sense to us high school physics students.

Rick

ps we used dry cleaning bags that were an absolute pain to work with.

[MisterQED]

I listed the solar balloon link as a construction link. I have thought about making a hot hydrogen balloon, but for one I haven't found a suitable dark plastic for the construction and the question of whether the heating would cause more problems than it solved. Many of the links I've found about balloon construction discussed tape construction, but the hot air people mostly seem to be using welded seems which seems superior. Though thinking about it, it would be interesting to create a hot hydrogen balloon to fly up, then vent the hydrogen and attempt to land again as a hot air balloon with a controlled top vent. Even with the slowest descent, it would be a miracle to recover the envelope intact.