Expect the unexpected
In the hangar at the Ft. Sumner Municipal Airport, Bowman checks his equipment and chats with HASP director Gregory Guzik.
“What are the winds doing up there?” Bowman asks.
“Still blowing east to west,” Guzik says. “We won’t see the turn-around until next Wednesday.”
The stratosphere houses winds that change direction—or “turn around”— twice a year. In the summer, the stratospheric winds blow from east to west. In the fall, typically in September, they switch. Today is Sept. 5, and the winds haven’t switched yet. The launch should happen in two days. If all goes well, the balloon will fly to an altitude of about 120,000 feet, float a couple hundred miles west, and then come down north of Flagstaff, Arizona.
Like clockwork, launch operations begin at 3 a.m. with a lot of coffee and not a lot of small talk. Everyone focuses on the job at hand, systematically running through checklists. By 5 a.m., the team rolls the gondola out of the airplane hangar. At 7 a.m., the engineers begin to inflate the 500-foot balloon with helium. The total suspended weight beneath the balloon is about 2,000 pounds that, when fully inflated, can fill an average football stadium. For a successful launch, conditions need to be perfect.
Bowman and the other researchers wait and watch nervously, aware that the launch could be called off at any time. By 8 a.m., it’s confirmed— the launch is a go.
The balloon takes off and, within 30 minutes, the lithium battery-powered payload floats 25 miles high. Thanks to radio signals from the Columbia Scientific Balloon Facility, the team finds everything running as it should be. Except for the balloon’s predicted flight pattern—instead, it hovers directly above the airport.
Apparently, the stratosphere turn-around occurred early. As the winds switch, there are a few days of no wind at all. With no wind, the balloon stays put.
This is unexpected good news. If it had flown west to Arizona, the engineers would have brought the balloon down that evening—before it could float over into Los Angeles airspace. Hovering over Ft. Sumner, the balloon can stay up overnight, allowing Bowman’s microphones and data loggers to collect many more hours of data.
The HASP balloon - at 25 miles high - is visible from the ground.
Keep it in the family
Infrasound microphones are highly sensitive, fragile—and very expensive— pieces of equipment.
Fortunately for Bowman, a physical acoustics lab in Boise, Idaho, produces infrasound microphones that are much cheaper and a good bit more durable than typical commercial models. And that lab happens to have a strong connection to UNC.
Infrasound microphone developed by the Physical Acoustics Laboratory at Boise State University.
“It’s the science family,” Jonathan Lees says, grinning. He is chair of UNC’s geological sciences department and Bowman’s advisor. “We started working on these microphones 20 years ago.”
In 1997, while preparing for an expedition to a volcano in Kamchatka, Russia, Lees received a call from a colleague, looking for a project for his graduate student. “I sent this student the design for an infrasound microphone and told him to build it,” Lees says. “Well, he built it and it didn’t work. So we used another microphone and that was our first data set.”
The graduate student was Jeffrey Johnson—a man who doesn’t quit just because something is hard. He returned to the drawing board to build an infrasound microphone durable enough to survive harsh volcanic environments. Today, his lab at Boise State University produces microphones that not only work—they work very well, even in volatile places.
“We’re recording infrasound all over the world with these microphones—on every volcano we go to—plus rivers, floods, eruptions, chemical and nuclear explosions,” Lees says. “Part of the future of monitoring the earth is monitoring this acoustic landscape.”
Through regular collaborations, Lees and Johnson have created a strong legacy of UNC and Boise State geoscientists—the science family–who always push the limits, whether the task at hand involves installing equipment at the summit of a volcano or launching a payload 25 miles into the sky.
Lees loves it when students come to him with a crazy idea. And Bowman has certainly done that while at UNC.
“He is so full of curiosity that he drives my science,” Lees says. “When I work with students, I treat them like peers. And Danny is one of the few people who can rise to the occasion to be a colleague even though he’s still a student.”