High altitude balloons

High altitude balloons is a subteam of Columbia Space Initiative. We built and launched high altitude balloons to near space. I was a member from September ’23 to December ’25 and took part in two launches.

Spring ’24 launch

This was the team’s first launch in nearly a decade. We launched from upstate New York with a projected payload landing in eastern Connecticut. The payload carried a GoPro, temperature and humidity sensors, and an altimeter, powered by an Arduino that saved data every few minutes for review after recovery.

We tracked the payload with a GPS module relaying its position to a handheld radio over APRS (Automatic Packet Reporting System), with a commercial GPS tracker as backup.

Problems

The first issue was the tracking. We lost signal from both units immediately after launch, and lost the payload. We later found that the two GPS units were interfering with each other.

I told the team that one unit would outlast the other, at which point it would start communicating again and we could recover the payload. That came true the next day. But another problem surfaced: the balloon was underfilled. A balloon expands as it ascends until it bursts, and an underfilled one ascends more slowly, so it is carried much further by wind first.

What was meant to be a 3-hour flight became an 18-hour one. The commercial tracker started pinging in the morning at 30,000 feet and descending. It was a few hundred miles off the east coast. We watched for half an hour as the payload fell into the Atlantic and went silent.

Fall ’24 launch

The goal was a successful recovery. We lightened the payload, used only one GPS unit, and verified the balloon was filled all the way. The frame was a simple plywood triangle with an Insta360 camera, a portable battery, and the GPS at each corner.

The launch was successful, but the balloon landed in a very tall tree in someone’s backyard in Connecticut. That someone turned out to be a professional tree trimmer. About a month later he cut down our payload and shipped it to Columbia.

At high altitude you normally worry about extreme cold. The Insta360 had the opposite problem: it overheated and shut off a few thousand feet up, so our footage covers the first half hour of a 2.5-hour flight. A cinematic video of the launch is on YouTube, courtesy of Claudio, a now-graduated team member.