A fuller write up (and hopefully pictures!) will come soon, but here's the result of today's launch. Unfortunate, I know. We'll come back with chainsaws tomorrow. Hopefully tonight's rain doesn't affect the payload too much

Tonight we performed successful drop tests with two different size parachutes, an Orange 50" one that I had ordered a long time ago and a black 24" one that came with my Norad Pro Maxx kit. The above video shows our first test with the 24" parachute, and as you can see it is not very gentle on the payload. However, tabulating data from the tests shows that the descent rate of the 50" parachute should be slow enough to provide a reasonable ground track. Below are the first predictions for the ground track of hte initial balloon launch.

Quite conveniently, the balloon is predicted to land 10-15 minutes away from my house! Of course, it's only a predictor, and I've seen other projects where people land 20 miles away from the predicted landing spot. And with my newfonud knowledge that the data for the model gets updated every 6 hours I'm not holding on to any sort of hope that it will land in such a convenient location :)

Working late into the night, I was trying to prepare the flight computer and relevant systems for a range test. I'd had poor results in earlier tests, and made the call that we would not launch if we could not get at least 1 mile of range on the radio.

But we never got as far as the range test. We had components outside, we were moving to the cars, when suddenly I noticed the flight computer had stopped transmitting. The transmitter was still on, but it wasn't doing anything. I re-uploaded the sketch to no avail.

Finally we went back inside and I did some more debugging. The SD card library that had been supposedly fixed for chipkit processors was having problems. After a file got too big, it would hang when trying to write, and stop the whole show. I looked at the data on the SD card and saw that the last time data had been recorded had been 30 minutes ago, despite the fact the flight computer was on the whole time.

Trying to fix the issues by switching flight computers led to damage to the SD card shield that we surprisingly weren't able to repair, even with the most primitive methods. Another decision I had made is that we had to log flight data to the onboard SD card. In the event the radio communications broke off, but we managed to find the payload either via the cell phone backup or some good samaritan finding it and calling us, I wanted to know the ground track of the balloon and the max altitude it achieved. This would help indicate how accurate the predictions were, and that seemed important enough to me.

So we're not able to launch the balloon, but the preparations to do so certainly got me closer to launching than I've been yet. The flight box is pretty much assembled, and it weighs about 2.5 lbs without batteries, comfortably under the FAA 4lb limit for such payloads. The flight computer has matured from breadboard to protoshield, and the code, while still having issues, is coming along. Most of the materials are in place, now we just need a new opportunity.

The rest of this post has some more details on the other tasks on which we made progress and the errors we faced.