Saturday, April 25, 2009

Last Chance Balloon

I am going to tell you some stories. The stories of four balloons (well, five balloons, as you will find out). I will start with the last and end with the first, since I am in a good mood.

I was in a pretty bad mood for this balloon launch, since we had just had basically three pretty unsuccessful balloon launches. I had a meeting for the undergraduate education committee first thing in the morning (and had to proctor an exam to a student who missed the "make-up" final, but couldn't come to the actual exam...) that went until 10:30. I had sent the team a pretty nasty-gram the night before saying that they better be absolutely ready to go by the time I got there. And they were ready! Well, almost ready. We had to stand around for 25 minutes talking about how ready we were and lots of other crap, until I said "Are you ready?" and everyone went "oh! yeah!" and we jumped into the cars and went.

We drove to Coldwater, MI, where we stopped for gas and food (although no one wanted to go to a restaurant - we just bought crap at the gas station - sort of crazy...) I got some Combos and a Mt. Dew (hey - they now have Mt. Dew "Throwback", which is Mt. Dew with sugar instead of Corn Syrup! Now Crab-Mama can't complain at all about my little habit (well, except for the ring around the belly.)) Then we were off to launch the balloon.

We exited on 69 South at exit 3, which is literally in the middle of Nowhere, MI. Well, not literately. As we were driving, I recognized that we were in Amish Country, since there was horse poo lining the road, and none of the houses had electricity or phone or cable or satellite dishes or cars on blocks. We found a nice little section of field, and I stopped at one of the houses to ask if we could use their field to launch our weather balloon. As soon as I got out of the car, there were about eight people standing on the porch staring at me. Since it takes nine Amish people to intimidate me, and not eight (six of which were kids!), I proceeded to explain about the project and ask if we could use their field. They agreed, so we started setting up.

The day was a very nice day for following a balloon, but it was a crappy day for filling a balloon, since the surface gusts were around 20 MPH. We set up close to some trees, which is strange, but with high winds, you want the wind to shelter you a little. Also, you launch with the trees to your back (pretend they aren't there, and they won't pop you balloon). So, we waited until the "last second" to start filling up the balloon. The wait was caused by them basically having to turn everything on inside their package, then sealing everything up properly. They had to make sure that everything was working properly, etc. Once that happened (about 30 minutes), we started filling.

Filling the balloon is adventurous, since it ends up being about 10 feet in diameter, which, in a 20 MPH wind, causes a drag force of about 100 lbs. That is a fair bit. So, you cover it with a big sheet and have four people holding it down. Once it is filled, you want to launch ASAP. Well, we filled it, and the other team members were playing around with the lines that attach the balloon to the payload. For about 20 minutes. Grrrr..... Finally, everything was ready, and we actually launched.

I should mention that during this time, we had an audience watching us the entire time.

We actually had good communication with the balloon for a while. The team had two radios, two GPS receivers, and two ground stations. Redundancy is good! Their two independent communication systems were on different power systems also. One of the ground-stations basically cut out after a little while, and they weren't really sure what was wrong. BUT, they were transmitting on this thing called the APRS network, which means that if any station in southern Michigan was listening to them, their location would go on to the internet! So, when one of their team lost communication, I fired up the laptop and blackberry and logged into the APRS website, where they were being tracked!

Here is the ground-track of the balloon off of the APRS website:

The balloon package had two cameras on it, one looking sideways and one looking downwards. If you want to see all of the pictures that they got during the whole flight, there are really, really cool. You can see them here.

Here are a couple images to tantalize your buds.

This is one of the first pictures from the downward facing camera. You can see the shadow of the balloon on the ground, which is sort of cool.

These next two are images from the balloon right around the time that it burst, which means it was about 95,000 feet in the air.

The final image is the last image that was taken by the downward camera before it crashed into someone's backyard.

For the last few balloons, people in the chase cars actually saw them burst. This is pretty extraordinary, since the balloon is almost 20 miles above the ground. It expands to about 30-35 feet across, and looks like a star in the sky. We try to keep almost directly under it the whole chase, since you basically know where it is if you can stay under it. When it bursts, though, you can no longer see it. Some people can catch sight of the radar reflector when it gets to be a few miles off the ground, but you have to great eyesight to do this. This comes in handy when you don't have communication with the balloon (as you will find out in story number 3!)

Anyways, we watched the balloon all the way up, saw it burst, tracked it on the APRS web site to almost the ground, then the lead car got communication back with the balloon. I lost the APRS web site for a while due to no cell phone coverage in the area. When I got it back, we tracked the balloon down to about 2,000 feet altitude. The other car got comms down to 760 feet, at which point they stated that "the balloon has really slowed down a lot". Meaning that it had hit the ground. I informed them of this. They were very excited. So, we got the exact location of the balloon and drove straight there. It was too bad that we didn't actually see it land - we were only about a mile away when it did.

We pulled up in a driveway of a house that looked abandoned, but had lots of "No Trespassing" signage. It was the last house next to some open fields. There were also open fields behind the houses. The students knew that it was somewhere behind the houses, so they just ran back there. There it was just sitting behind the third house in. The people who lived in the house right in front of the field came out and talked to us about things, so we got their address and promised to send pictures. The students gathered up the balloon and ran back to the car. They opened it up and discovered that they hadn't taped down the batteries, and so thought that maybe they wouldn't have any pictures at all. The cameras came out and the SD cards were put into a computer, so they could see the pictures, which everyone loved. After this, we all piled into the cars and drove back.

The end!

1 comment:

Jay said...

I'm a student who reads your blog semi-regularly and wondering if there's any way you could post some of the info you use to teach this class and your rocket class. Seems like the kind of practical information lacking from most curriculums and I would interested in what lecture notes you give in preparing your students for this. If this is too dry for a post hopefully you can see my email via my comment. Thanks.