Up, up and away
Father-son team launch weather balloon
By Phyl Newbeck
For The Essex Reporter
It was a father-son bonding experience that brought Kevin Wrenner back to his roots. “I’ve always had an interest in weather, science, astronomy and electronics,” he said “and I try to share those passions with my children.” Thankfully, Kevin’s 14-year-old son David has some of the same interests, so, together they assembled and flew a weather balloon from their Essex home. The launch of Leo I took place on July 6, a date chosen because of the light wind and clear skies.
A senior design engineer at Linear Technology, Kevin learned that some high schools were taking part in a Global Space Balloon Challenge and decided it would be fun to do something like that with David to finish off a year of homeschooling. “I had launched some helium balloons when I was David’s age,” he remembers “with typewritten notes in sandwich bags and return postage. Some went for a couple of hundred miles and some people sent back notes.” In 2009, MIT students flew a high altitude balloon with a camera and that balloon was the catalyst for the Wrenners’ project.
It took the father-son team two months of on and off work on weekends and evenings to research and build their balloon. The creation was a simple Styrofoam box with a miniature computer, two radios (for redundancy), two homemade antennae, a small embedded camera and a parachute. The Wrenners chose radios because cell phone coverage in Vermont can be spotty. The flight took two hours and six minutes with roughly four-fifths of the time ascending. “It came down faster than we intended,” David said “because the parachute was undersized.” The Wrenners were able to track the path of the balloon on their computers before jumping into their car to fetch it from its landing site in Monkton. The balloon was fitted with a beeper and a flashing light to aid with the recovery.
“You launch and hope for the best,” said Kevin, noting that when they set out to retrieve the balloon, they carried tree climbing equipment and backpacks in case they needed more than one day for the trek. The owner of the landing site gave them permission to cross his land but they had to ford a stream, climb over a barbed wire fence, and bushwhack through grass as tall as David. It could have been much worse. The balloon landed within the five mile radius indicated in an online flight predictor, but Camel’s Hump was also within that delineated area. “It was really cool bushwhacking and then suddenly there’s a bright splotch of orange and this thing we had lovingly sent into the air hours before was chirping in the grass,” Kevin recalls.
Although the Wrenners picked a clear day for their launch, they had neglected to factor in regional wildfires which made some photographs a bit hazy. Nevertheless, David was able to put together a four and a half minute video of the flight, complete with statistics. The balloon reached a height of 110,760 feet and recorded a low temperature of -66. It travelled in a zig-zag pattern, heading down to Duxbury and then towards Hinesburg before landing. It rose at roughly 1,000 feet per minute and fell at 300 feet per second. The balloon burst at approximately the height the Wrenners expected, based on an online calculator. One interesting fact is that once the balloon cleared the troposphere, the temperature began to rise slightly in the stratosphere.
Since the balloon was under four pounds, the Wrenners did not need permission from the airport to fly it, but they gave a courtesy call to the FAA to let them know their flight plans. The video has a brief view of a jet flying below the balloon. The duo has not ruled out the idea of another launch next summer. David, now a ninth-grader at Essex High School, definitely enjoyed the project. “Getting the video and watching the raw footage the same day was cool,” he said. “It’s amazing what hobbyists can do these days,” said Kevin, thinking back to his helium balloon days. “This is stuff we couldn’t have dreamt of a few decades ago.”
The Wrenners’ video can be seen at Tinyurl.com/wrenhab1