[Space] space is hard, let's go shopping!

Mikolaj Habryn dichro at rcpt.to
Mon Dec 21 22:38:25 UTC 2009

On Mon, Dec 21, 2009 at 1:13 PM, miloh <froggytoad at gmail.com> wrote:
> On Mon, Dec 21, 2009 at 12:11 PM, Mikolaj Habryn <dichro at rcpt.to> wrote:
>> I have two 8' latex meteorological balloons on the way -
>> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330370803471
> "Experiments using a balloon like this will not be forgotten."
>> After ordering, it occurred to me that my simple idea for stopping
>> ascent below burst-height (a pressure-relief valve) wouldn't work on
>> these anyway since they're stretchy, so the pressure inside is always
>> going to be substantially higher than outside, and the difference will
>> probably vary with altitude. Which leaves open the question of what
>> else we'd like to consider doing with our first launch?
> Are you still interested in other ideas for feedback mechanisms?
> perhaps a semi-elastic ring/girdle set to control relief as the balloon
> diameter increases to bursting point?

Definitely! The simpler the better, provided it doesn't freeze open :)

> These ideas are coming from my completely naive  standpoint, I would like to
> gain more insight, so if anyone on the list has reading references please
> post links or wikify them on noisebridge.net
> (btw, mikolaj, if you get resistance to adding wiki plugins from ops, I'll
> be asking for 'nosebridge' to be repurposed as a plugins sandbox.)
>> The standard equipment is a camera, gps, and radio transceiver, but we
>> can aim higher than that - I think the FAA plain doesn't care what we
>> do up to about 6 pounds (maybe 4?) but with two balloons, we can loft
>> significantly more (perhaps with extra paperwork?). A model rocket
>> should be doable either way (maybe we'd need three balloons to make a
>> stable launch platform?) - and putting the camera on the model rocket
>> pointing downwards to watch the launcher fall behind with earth
>> curvature in the background would make for fantastic youtube :)
>> Other ideas?
> What's the time and $$ budget for balloon launches over the next few
> months?  Could we manage a set of ~ 3-5 launches that span everything from
> vanilla balloon video, interesting descent cannister designs, and ascent
> tests from balloon platforms?

I'd love to have a monthly launch schedule that takes up whatever is
ready at the time, but we should get an idea of how hard this is to do
first :) As far as budget goes, sure - I suspect a few of us are
already in a position to underwrite multiple balloon launches
singlehandedly (I'd certainly be game), so assuming we can recover the
electronics with some reliability, there's no reason we couldn't have
a fairly long roadmap. That's assuming we don't run out of ideas for
what to do, of course :)

> Total launch costs for single balloons are around .5k?

Around $100 non-recoverable costs for balloon and helium, assuming the
size of the ones that I posted earlier. Probably a couple of hundred
dollars minimum of electronics for FAA compliance etc, but with any
luck we'll recover those fairly consistently.

> I'm interested in looking into managing gas procurement and storage, if you
> want to divide up the labor and manage a set of balloon launches with a team
> of spacebridgers...

For sure - and in fact, one of the things I'm keen to look at is
hydrogen lift which should be much cheaper than helium. I asked the
guy that I ordered the balloons from about it, and he said:
Yes, I've filled one with hydrogen.  Calcium hydride is what the
government used and what I used to make the hydrogen.  I have lots of
it but it's very expensive to ship because it's regulated hazardous
material.  You just drop it into water and H2 comes boiling out of the
water.  You can also use magnesium and hydrochloric acid, or iron
powder and hydrochloric acid.  All of that's pretty pretty dangerous
to mess with.  A small regular balloon filled with hydrogen makes a
fireball about 3 feet in diameter so a weather balloon filled with it,
well.... it would light up the entire sky.... or kill you if you were
next to it on the ground.

So now I want hydrogen fill *bad* :) I think getting the
infrastructure right to safely do remotely triggered filling and
release would be a grand project on its own (but we should definitely
use helium the first few times!).


> -rma
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