Ballooning in the Shadow of the Moon

This image, courtesy of the South Dakota Solar Eclipse Balloon Team, shows the moon's shadow crossing the Nebraska Panhandle during the Great American Eclipse of 2017.

At 10:35 a.m. on August 21, 2017, in a field in front of a small Nebraska Panhandle farmhouse, a team consisting of SD Mines students, Black Hills area high school students, teachers and community members, meticulously followed a set of steps they had practiced many times before. Payloads were carefully secured, batteries checked, and scientific instruments turned on and tested. Soon, helium was coursing through a hose from tanks in the back of a pickup truck into an eight-foot-tall balloon laid out on the soft grass.

Above the desolate cornfields and sandhills of northwestern Nebraska the moon was starting its path across the sun–the arc of its shadow racing across the country toward this team. The Great American Eclipse was underway.

The South Dakota Solar Eclipse Balloon Team had been working for two years to prepare for this one sliver in time. Their goal—to launch this balloon at the exact moment to loft the payload to an altitude of about 100,000 feet, under the moon’s shadow, during two minutes of totality. On board were video cameras, a radiation detector, GPS, and other scientific experiments. This project aimed to capture images and data from the eclipse. The radiation detector would help measure the flux of cosmic rays in the upper atmosphere as the moon obscured the sun. The video cameras would capture the circle of the moon’s shadow on the earth. The team designed and built some of the payload, including a special device to stabilize the video camera. They researched other components, measured every ounce, tested and retested the devices and completed multiple practice launches all to hone their ability to get this one chance right.

Gina Bestgen (ME 17) was the Deputy Project Manager. One of her jobs was to study wind weather patterns to determine the best launch site in the zone of totality. By the morning of August 21, Bestgen had spent the better part of the past 72 hours poring over the data. “I was going back and reviewing all the calculations and validating them and making sure data were making sense,” says Bestgen. “The predictions that were provided to us were not accurate. They were using a favorable number for the ascent rate that didn’t include the correct weight of our payload,” says Bestgen. She worked up a diagram, laying out the data with various options for the launch location, and met with team members. Forty eight hours before eclipse day, the team made the decision to move the launch site ten miles to the northeast. A scramble ensued to find a new location and inform the media, community and Federal Aviation Administration. Bestgen says it was the trust of her team in each other that led to the right decision. “We would talk all the way around and each give our input to make a decision like this,” she says.

At 10:45 a.m., launch team members released the balloon to cheers and a collective sigh of relief. Some 50 miles away, at Alliance High School, the ground station team was gathered, along with two vanloads of  SD Mines physics students, a dozen local high school students and many community members and  visitors. They live-streamed video and tracked the GPS location of the balloon so they could later  retrieve the payload that would parachute to earth after the eclipse.

But for the next 45 minutes, team members could pause and take in the progression of the celestial event playing out above them. In the wide open Sandhills of Nebraska the launch team was able to view the giant shadow of the moon–like a wall of darkness–as it progressed toward them. In the air their balloon was capturing images and data the entire time. For Bestgen, who has spent so much time focused on the balloon project, the experience of totality was surprisingly profound. But, making the experience even more amazing–she believes the team caught a glimpse of the balloon itself during the eclipse. “While we were viewing the eclipse, there was this little white dot near the ring around the sun,” says Bestgen. “We were astonished to think this was our balloon,” she adds. “The white dot was where the balloon was predicted to be in the sky, it was just reflecting light from the eclipse.” The image is captured on Bestgen’s cell phone video.

Later that afternoon, the chase team successfully recovered the payload. Team members went back to  the lab and shared data with other teams across the country and with NASA. Much of these data are still being analyzed. But the video and photos from the onboard cameras are the first images ever captured of the moon’s shadow crossing the Nebraska plains during an eclipse. The South Dakota Solar Eclipse  Balloon Team was one of fifty-five teams from across the country that captured video, photos, and data of the total solar eclipse. NASA and the South Dakota Space Grant Consortium sponsored the SD Mines based project.

Peggy Norris, PhD, Deputy Director of Education and Outreach at the Sanford Underground Research Facility (SURF), led the team. “For a team with no experience in ballooning to successfully collect data from near space during a 2.5 minute window of totality was no mean feat. It required teamwork and careful planning. For me, it was most rewarding to watch a diverse group of individual undergraduates, high school students, teachers, faculty and community members evolve into a cohesive team working together to achieve this goal, solving many problems along the way and learning from each other,” says Norris.

Solar eclipses have spurred changes in history–they have upended naval battles, deposed kings and caused general chaos and mayhem among confused ancient populations. Eclipses have also been the center of intense scientific study, from the ancient Greeks who built machines to compute and predict their timing, to the total eclipse of May 29, 1919, when astronomers measured the sun’s gravitational bending of light in support of Albert Einstein’s general theory of relativity, to this small team of students who launched a balloon from the Nebraska Panhandle to contribute important data to a nationwide study of the Great American Eclipse of 2017.

Last edited 5/17/2018 9:53:34 PM

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