Even More Progress

Balloons!!! (well, actually one balloon)

So, we finally got far enough in our project that we were able to buy a balloon! We decided to go with the $60 20 ft 600 gram Professional Weather Balloon sold by Aether Industries. The other option was a 1200 gram balloon for $105, but the smaller one is more suited to our purpose, although we may suffer a loss in altitude as a result. Predictions put us around 90k ft, but that's all they are: predictions. The actual altitude may go up or down from that. We figure that the balloon will need about 70 cubic feet of helium to achieve 2kg of lift and 4.94 m/s rate of ascent. We haven't yet lined up a helium dealer, but I will start calling all the local places to find the best price. When the balloon finally does arrive, we have to insert a short length of PVC and zip tie it in place so we can attach the payload lines to it. We'll be sure to take a video so you can see how it's done as well as see what the balloon looks like. When handling the balloon, we will have to wear latex gloves to prevent any oils from degrading the balloon and causing a premature burst. 

Near Space Capsule

Yeah, the only thing that's changed here is we painted it black (Rolling Stones' "Paint it Black" plays in the background) and made a better fitting mount for the GoPro. We also purchased a GoPro Battery BacPac and ran a test, it added about 90 minutes extra battery life, which should give us plenty for the entire mission. I should start calling it the "GoBroke" because that's basically what I'm doing for this enterprise. GoBroke. And instead of "Be a Hero" as the tagline, it'll be "Spend All Your Money Sending Me to Near Space Without the Certainty of Getting Anything Back." 

Calculations

I don't really feel like going into much detail about how we calculated ascent rates and stuff like that, but I'll tell you it did involve quite a bit of metric/imperial unit conversion. For those of you who don't know, imperial is the set of units we use here in 'Murica. Our calculations required very involved and in-depth operations such as Googling something like "ascent rate calculator" or "burst height calculator", plugging in a bunch of numbers, and pressing "calculate". In all seriousness, though, it was no easy task to juggle a bunch of variables, units, and ideas around and come up with results. For example, when calculating the lift we would need, we searched through different resources to find suggestions for lift/weight ratios or positive lift. One resource said to have a 3:2 lift/weight ratio, while another said to have 4 or 5 lbs positive lift, and yet another said to have 500g positive lift. We decided to trust the 500g measurement; The example presented on the site was a situation very similar to ours. 

Weight n'stuff

The capsule ended up weighing 520 grams, and 780 grams if  you add the chute, the radar reflector, and the nylon rope. The balloon, of course, weighs 600 grams, and we decided to give the capsule a 620 gram positive lift to bring the total to a nice, round, 2 kilograms. Because 1 cubic foot of helium can lift 28.2 grams, we will need about 70 cubic feet of helium. (are you double checking my math? because trust me, I did it right). That brings us to a nozzle lift of 1400 grams (lift of balloon considering weight of balloon). This can be accomplished using a counterweight of 1400 grams and filling the balloon until it just lifts the counterweight. 

Well, that's all I have for you for now. Sorry, no media today. Yes, I realize it's been two weeks since the last post and things are starting to get redundant. But it's all coming together pretty quick. I'll probably have some more interesting, more humorous things to come that'll fill up the time between finishing and the launch date. As always, check back often, and don't hesitate to drop us a line at nearspace13@gmail.com.