"I've done this so many times — this is probably my 30th launch or something," she says.

The scientific goal of this project is to study the atmosphere. As the eclipse shadow travels from south to north across the U.S., it briefly cools the air. Bowden says it's like dragging a swizzle stick through a cup of hot coffee.

"The eclipse itself is kind of stirring up the atmosphere as it traverses across the country," Bowden says. "What we're looking for is the signature, or the effect, of the movement of the shadow."

The results will teach researchers more about how heat moves through the atmosphere. The data could be used to improve predictions of both weather and climate change.

When it comes to making these measurements, there's no better vehicle than a balloon. Unlike a rocket, balloons can drift gently in the eclipse zone for minutes or hours. And they travel at 75,000 to 80,000 feet in altitude, twice the altitude reached by a typical airliner.

Grammer says the view should be amazing.

"Hopefully we'll have livestream video from the balloon in flight," he says. "You'll see the shadow move across the Earth, and it'll be super cool to look at."

Runaway balloons

Things at the test launch appear to be going smoothly, but then, as Siddiqui begins to check her balloon to make sure it's got enough lifting power, it suddenly breaks loose and floats skyward.

The whole team watches as one of their two balloons drifts slowly away.

Nobody panics. The students put their heads together to figure out what happened. It turns out they forgot to reset a device that is supposed to cut the string at the end of the flight. Normally, this allows the balloon to float away, and the scientific equipment to parachute back to the ground, where it can be recovered.

Instead, the device cut the balloon loose before the payload was even attached.

"I've never seen that happen!" Meredith Embrey says with a laugh. The junior is in charge of tying the scientific equipment to the balloon.

"The good thing is, we didn't lose the payload itself, and we always bring two spare balloons and double the amount of helium we need," Embrey says. "So we will start inflating and do another balloon."

It's a moment to learn from, and that's exactly the point.

"The great thing about the program is that it's really both an education program and a research program," says Angela Des Jardins, a physicist at Montana State University and the principal investigator of the Nationwide Eclipse Ballooning Project.

Across the U.S., over 750 students making up 53 teams are participating in this project. The budding engineers are in charge of everything from scientific instruments to flight direction, weather forecasting, tracking stations, and more.

"We're trying to give these students an opportunity outside the classroom," she says. The eclipse balloons are "a science project that gives them a little bit of a taste of what it would be like in the real world, working in an aerospace job."

Balloons are a perfect prelude to launching rockets, says Bowden. "It's a microcosm of a NASA launch, but cheap and fast — and you can do it again if you fail."

Which is exactly what the team is doing now. With their string-cutting device fixed, they're racing to inflate another balloon. They've got to be quick because the wind is picking up. Siddiqui seems to love it — using engineering to solve problems on the fly, under pressure. She says she hopes to someday have a career launching rockets.

"Maybe like a flight controller/flight operator-type person for my full-time job," she muses as she watches the second balloon fill.