When NASA TV live streams North America’s total solar eclipse on April 8, it will likely include jaw-dropping footage of what the eclipsed sun and the moon’s shadow look like from near space. It will come from some of the numerous helium weather balloons set to be launched 100,000 feet into the moon’s shadow from across the parts of 15 U.S. states visited by the path of totality.
The NASA-funded Nationwide Eclipse Ballooning Project is part science, part broadcasting. While some of the balloons will livestream 360-degree video and photos, others will collect data on what happens to Earth’s atmosphere during a total solar eclipse.
Stratospheric Eclipse
During April’s eclipse, balloons launched from 34 sites will be live-streaming the eclipse to the project website and YouTube using the latest Raspberry Pi cameras. The balloons will fly at an altitude of 80,000 feet in the stratosphere, where the sky is black and the curvature of the Earth is visible.
The original project, which went live for the last total solar eclipse in the U.S. in 2017, saw 55 balloons livestream the moon’s shadow moving across the Earth to 600 million people on NASA TV.
During that eclipse, the balloons flew along the path of totality for about 90 minutes, capturing images and data from different altitudes. The balloons will fly for four to six hours during the upcoming eclipse, depending on the location.
It’s a collaborative effort between NASA, Montana State University and 53 teams of over 750 students across the U.S.—including 30% minority-serving institutions and 15% community colleges. NEBP aims to inspire the next generation of scientists and engineers, but its atmospheric science goals are real.
Great Opportunity
The impetus for this latest attempt is the incredible coincidence of having two central solar eclipses visible from the U.S. within six months. Last October 14, an annular solar eclipse was visible from a 125-mile-wide track across the U.S. Southwest, during which the NEBP launched 550 balloons. “With this geographical coincidence comes the chance to compare and contrast what happens during two different kinds of eclipses, one with a deep moon shadow and one where a substantial portion of the sun is obscured,” said Angela Des Jardins, a physicist at Montana State University, Bozeman, who leads the NEBP. “It’s a great opportunity to observe what’s going on in the atmosphere during both types of eclipse.” A
bout 91% of the sun was blocked by the moon that day to produce a “ring of fire.” On April 8, the sun will be totally eclipsed from within that path of totality.
The project also aims to compare and contrast the observations from 2017 with those from 2024 and study the differences between the two eclipses. Balloons were also flown in the total solar eclipses in South America in 2019 and 2020.
Hunt For Gravity Waves
On April 7 and 8, 19 teams will fly balloons every hour 24 hours before the eclipse and 6 hours after. Armed with radiosondes, these balloons will collect atmospheric data and, with luck, capture data indicating “gravity waves.” These are waves moving through a stable layer of the atmosphere, creating rows of clouds and clear areas between the rows of clouds, according to the National Weather Service.
They’re typically generated by mountain ranges and by day and night temperature differences. “It was theorized since the 1970s that the cold dark shadow of a total solar eclipse would generate strong, sharp gravity waves high up into the atmosphere, but they had never been observed in the stratosphere prior to our July 2019 campaign,” said Des Jardins.
Success In October
On October 14, these gravity waves, including stratospheric ones, were seen, photographed and detected. “The eclipse went well, and every team had at least some success,” said Des Jardins, who imaged gravity waves from Nevada. However, while eclipse chasers pray for clear skies, the hunt for gravity waves comes with a different requirement. “We don’t want really bad weather—just a little bit of cloud,” said Des Jardins. The balloons are sensitive to high winds and thunderstorms and cannot be launched if the weather conditions are unfavorable. The team will be monitoring the weather closely in the days leading up to the eclipse and making decisions accordingly. “It’s going to be really exciting,” said Des Jardins. “No one’s ever done anything like this.”
For the very latest on the total solar eclipse—including travel and lodging options—check my main feed for new articles each day.
Wishing you clear skies and wide eyes.
