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.