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Alphabet’s Loon sets a new record for longest stratospheric flight

It stayed aloft for 312 days while circumnavigating the globe.


Google parent Alphabet has revealed that one of its Loon balloons spent 312 days aloft, breaking its previous stratospheric flight record of 223 days, by a wide margin. It had quite a journey during that time, launching in Puerto Rico and heading to Peru, where it provided three months of test internet service. It then circumnavigated the entire globe, passing over the South Atlantic, Indian and South Pacific oceans, before being picked up in Baja, Mexico — some 10 months and 135,000 miles later.

Alphabet said that it hit the milestone through a combination of design, materials science, manufacturing and how the balloons are flown. For instance, the team flies “millions of simulated flights before we even get started on the hardware,” wrote Loon CTO Salvatore Candido.

It can also now build them so there are no tiny defects that can drastically shorten flights. “We’ve been able to figure out how to reliably and at scale cut, seam together in a pumpkin shape, wrap up, stuff in a giant box, and ship balloons across the country to our launch sites,” Candido wrote. The company also learned how to fill the balloons in around 45 minutes and shield them from wind while doing so, ensuring they don’t get battered by the elements before launching.

And when they do fly, Google monitors “hundreds of telemetry data streams related to flight system performance,” adjusting ballast and other parameters to maximize flight time. All the balloons are recovered when they land, if possible, then analyzed using “what is essentially the world’s largest... flatbed scanner,” allowing engineers to analyze them and make improvements.

All of that work means the Loon balloons can stay aloft longer, lowering flight costs per hour. It should also make for more consistent connectivity — especially if the balloons are deployed to provide internet service in remote areas around the world, as Alphabet hopes.