On eclipse day, hundreds of students will send up balloons for science

Student volunteers prepare a balloon for a morning launch in Cumberland, Md. On April 8, eclipse day, hundreds of balloons will be launched into the path of the eclipse to study the atmosphere. (Meredith Rizzo for NPR)

CUMBERLAND, Md. — It's a chilly March morning, and Mary Bowden is standing in the parking lot of a local community college.

Bowden is a professor of aerospace engineering at the University of Maryland. Nearby, her students are hustling around on a bright blue tarp, rolling out heavy cylinders of compressed gas and fiddling with boxes of electronics.