Posts tagged Spot

Last Saturday was the big day. After an incredible fundraising period, lots of work programming, designing, and testing, and hours spent on the phone making sure everything was ok with the FAA, it was time for Astdroid’s first launch.

We woke up at 5:30AM, drove up to Boulder, CO (about 40 minutes from Denver) rolled out our big tank of helium and got to work.  My wife (@erinpier) streamed on her phone via UStream allowing people from all over the world to watch. The weather was perfect. We had donuts. It was great!

We were scheduled for a 7:30 launch time and were in the air at approximately 7:46. The balloon rose directly over head for about 30 minutes before moving south as we had anticipated. We noticed it rising a little slower than expected as we watched Astdroid Live while the HTC Evo and the Astdroid application were sending back data. Other than that things looked good. The application told us the craft’s position, temperature, speed, elevation, and battery percentage. It was working marvelously!

Once the balloon was less than a speck in the sky we decided to reward a launch well done with a coffee and a small breakfast before heading back to Denver and ultimately preparing for the recovery part of the journey. At about 9:30 we saw that Astdroid had stopped reporting it’s location at about 30,000 feet, just like we had expected, as the cell towers were no longer in range for a 3G connection. No worries, we still had updates from our SPOT GPS (though only at 10 minute intervals as opposed to 30 second intervals) and knew we were still on course, drifting across Denver heading for Colorado Springs.

At 10:11AM the updates from SPOT had stopped. We waited for a bit knowing that sometimes the SPOT missed an update. 20 minutes became 30 minutes became an hour. Something was wrong. At 10:11AM we went from everything going as expected to not knowing what had happened.

So, here is where things become speculation:

• The balloon rose more slowly than was expected in part due to a heaver payload than recommended. Our payload was just under 880 grams while the max was 905 and the recommended was 605. We figured that accounted for the slower rise up. We also believe that means the balloon never reached its ceiling (90,000 feet).
• Because of this, the balloon likely popped at a lower altitude.  My guess would be somewhere in the neighborhood of 60,000 feet.  Though that’s only a guess.
• The transmission at 10:11AM was the last one before Astdroid reached ground, landing in a way that didn’t allow for it to communicate its location.  Upside down?  In a valley?  In pieces?  Who knows.

We went and checked out the last known location.  No luck spotting Astdroid.  The unfortunate thing about the SPOT GPS is that only updates every 10 minutes.  If that was indeed the last update before it hit ground it might have traveled an additional 30 seconds… it might have traveled the full 10 minutes… that’s alot of range.

It was beginning to get dark so we went home that evening empty handed.

That night we took a hard look at the data.  Here’s what we came up with.

There were 2 possible scenarios.  The SPOT GPS had stopped operating for an unknown reason in midflight, thus leaving us with absolutely no idea where Astdroid may have landed OR we were correct in assuming that it had stopped transmitting due to it’s position on the ground.  Being that the second option is the only one that would allow us to recover Astdroid, we pursued that avenue.

Here’s what we have from the SPOT GPS tracker:

Using that we were able to take a look at the speed between updates:

The distance deltas dropping from 9 miles to 4 near the 3rd and 2nd to last points lead us to believe the balloon burst and fell before drifting to the ground.

As you can see this aligns nicely with the idea that the balloon burst and fell (quickly) as expected before the parachute could open (at an elevation of 60,00 feet there would not be enough air for the parachute to open) before drifting.

This would mean that if the payload were moving consistently with these speeds, or better still, slowing down, then the payload would have been travelling at about 20 mph.  At 20 mph with a maximum interval of 10 minutes that would mean that Astdroid were within a 3 mile radius of the last known point.  Adding to that the knowledge that Astdroid was travelling almost due south at it’s last update, we conjectured that it fell within a cone of about 3.3 miles.  So that’s what we decided to explore.

The next day we decided on another recovery attempt, armed with much better knowledge.  We were able to do 1 mile sweeps from the last known point, but we saw nothing.

Blue line - The SPOT GPS Track. Orange polygon - 2 mile cone. Yellow polygon - 4 mile cone. Red line - GPS track of explored area

We covered almost 4 miles on foot with no signs. To cover the entire area is almost impossible as it grows exponentially with each mile in radius. The area is populated, but not heavily.

I’m still optimistic, hoping any day somebody will call and say they found a strange cooler in their backyard.  I have some ideas about enlisting the help of some local geocachers to go explore. However, it must be said that there’s a possibility it will never be found.

There were many, many lessons learned from the experience and this has by no means ended the project.  Next time we will be better armed with knowledge, experience, and data!

I’m posting all of the data from the Astdroid launch here.  If you’ve got an ideas, send then my way!

Google Earth KML of SPOT GPS track, Projected Cones, and Explored Tracks

SPOT GPS gpx file

SPOT GPS csv file

I’d love to have written this post sharing incredible photos of space with you, but this time it was not to be.  Next time, next time we will have our due success.