As soon as August, a giant silver bullet will cut its way through the dry air of the southwestern US and cross the Pacific to reach the coast of Japan. 

Once there, the roughly 200-foot-long craft, built by the New Mexico–based company Sceye, will park some 18 kilometers above the ocean’s surface, in a wispy-thin layer known as the stratosphere. Then it will use a custom-built antenna to supplement Softbank’s 5G network, a test that will include beaming data straight to devices. 

Sceye (pronounced “sky”) is one of several firms building a class of airborne craft called HAPS, or high-altitude platform stations or systems. Such a platform can be a plane or a balloon or, yes, an oblong craft filled with helium and outfitted with solar panels. HAPS companies, including the Airbus subsidiary Aalto, envision them serving a variety of lofty purposes, such as delivering internet service to disaster sites and observing Earth’s surface. 

COURTESY OF SCEYE

The stratosphere is a good place to be if you want to cover a large area. It’s also much closer to the ground than even the lowest-orbiting satellites, which means sending down a signal takes far less energy. “What we ultimately offer is space-like conditions, without the cost of going to space and without the complexity of being in orbit,” says Mikkel Vestergaard Frandsen, Sceye’s CEO and founder.

But it’s also not so easy to stay there. Sceye’s aircraft, Frandsen says, has to be light enough to stay aloft but also strong enough to carry the necessary systems. It must soak up and store enough solar energy during the day to provide around-the-clock power to an electric fan that can maneuver the HAPS back into place when winds knock it out of position—mettle it proved in a 2024 test flight.

Since then, Sceye has been preparing for its big Japan test. In the flight pictured here from this spring, for example, the craft stayed aloft for 12 days as it flew to the coast of Brazil and spent more than 88 hours “parked” in various locations. Eventually, the company expects its platform could help satellite operators better serve densely populated areas.

Someday, Frandsen says, spotting a HAPS may be as common as seeing ships at port or trains on the tracks.