Trying to send something to space by attaching it to a balloon and letting go sounds like a plan concocted by a six-year-old. In fact, we’re pretty sure a lot of you tried it back in the day, only to witness your probe snag on a tree branch fifteen feet up. But it turns out when you’re NASA, and your inflated balloon is 1,000 feet up, that pre-school plan graduates into a great platform for stratospheric science.

Earlier this week, the US space agency sent a high-pressure balloon skyward from Wanaka, New Zealand, with inflated hopes that it will stay up there and circumnavigate the globe for 100 days or more—a flight time that’s about twice the current record. Along for the ride is the Compton Spectrometer and Imager (COSI), a gamma-ray telescope developed by scientists at UC Berkeley.

Staying aloft for 100 days is a pretty big deal. Previous balloons relied on sunlight to keep the gas inside thermally expanded—hot enough to float. The problem with that is the sun goes down. There are work-arounds, like launching from Antarctica during its summer when the sunlight is constant, but infrastructure issues alone mean that the southernmost continent is never going to be the ideal place to set up shop.

But if you create a closed, pressurized system, the balloon isn’t beholden to solar energy to give it lift, which gave NASA more launch sites to choose from. If all goes well, the Wanaka flight will prove that the super pressure balloon technology is capable of the consistent, long-duration flights that scientific instruments need if they’re going to collect meaningful data.

Steven Boggs of UC Berkeley calls this a super pressurized inflatable guinea pig. If it works, it will give scientists like himself deeper insights into nuclear physics. For instance, COSI detects gamma radiation emitted when new elements are created—something that happens when a star Hulks out, goes supernova, and puts the stuff at its center under incredible pressure and high temperatures. “You can never recreate these conditions on Earth,” Boggs says. “So we’re using the cosmos as our laboratory to test our understanding nuclear physics.”

Boggs’ gamma-ray telescope was designed specially with the super pressure balloon in mind. But why even use a balloon at all? Sure, science always has room for whimsy, but balloons are finicky: Scientists have been down in Wanaka waiting for just the right wind conditions since the second week of February. Plenty of other options (like satellites) are not inclined to plummet to Earth every time the sun goes down, nor are they at the mercy of atmospheric weather.

Balloons are cheap. Even really big balloons, filled with rarer-by-the-day helium. Way cheaper than a satellite. And balloons are easier to build, which, combined with low cost, makes them a great democratizer of space science. Plus, launching a balloon requires a lot less red tape than firing a rocket, shaving years off the prep time required for each mission.

“This is a great training ground for the next generation,” says Debbie Fairchild, NASA’s Balloon Program Office chief. “They can design, build, and fly their project in the time period of their PhD. We have grad students actually down there babysitting their payload before launch, which is something they wouldn’t get to see for many years if we had to send them up on satellites.” And besides that, each launch is an opportunity for those scientists to reconnect with their inner child.

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Balloons. NASA Is Using Balloons to Study Space