1st Balloon Launch - March 7, 2014

First test balloon launch was nearly a disaster.  It turned out successful, but I nearly lost the entire setup.  The balloon prep took a bit of work, but as the first launch, it was to be expected.  Eventually, we got it together and sent it up, and it worked very smoothly.

The camera on board didn't get a good video, since it was moving all over the place.  So, here is a snapshot of the video from above.

One thing I forgot to account for, however, was upper-level winds.  It wasn't too bad at the surface, but the winds just 100 ft up were extremely strong.  As a result, the balloon got pushed down by the wind.

As I tried to reel the balloon back in, the recovery system failed.  As a result, I lost ahold of the entire setup, and it started to fly away.  Luckily, there was enough line on the spool that it kept to the ground.  I grabbed it and kept it from getting away.  But too late.  The line got tangled in the trees, and there was no way to get it down.  So, after a couple hours of trying, we gave up and decided to wait until Monday to see if it would come down on its own.  Turns out the balloon popped that night.

Recovering it on Monday was also an adventure.  It landed in a cow pasture.  When we arrived at the field, the cows were on the other side of the field, so there was no problem.  We wandered in and found it quite readily.  When we turned around, the cows (and a bull) had followed us to our side of the pasture.  So, we had to go into the woods and crawl under a fence.  But, we got it back, and we were safe.

Here are the data plots for the launch:


A few points to note:

• In both the temperature and pressure plots, there is a large bump in the data between 14.65 (about 1440 UTC) and 14.70 (about 1442 UTC).  A rise in temperature and an increase in pressure both indicate that the balloon somehow lost altitude.  During the launch, at this precise time, the wind picked up very strong. But since the balloon was tethered, it got pushed farther away, but the only away it could get was down.  So there was in fact a decrease in altitude for those moments.
• The temperature drops with altitude as expected.  In the final figure, the blue points indicate the measurements as the balloon rose.  The red points are the measurements after it reached peak altitude.  The air temperature appeared to drop at a rate of about 20*C/km.  This doesn't exactly seem reasonable, so it needs some investigating.
• The initial altitudes are showing that we were 100m below sea level.  Looks like we had a calibration issue.

So, there was a lot to learn, making this a successful test launch.