High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen that are released into the stratosphere, generally reaching between 60,000 to 120,000 feet (18 to 37 km).
The most common type of high altitude balloons are weather balloons.
Other purposes use as a platform experiments in the upper atmosphere.
Modern balloons generally contain electronic equipment such as radio transmitters, cameras, or satellite navigation systems, such as GPS receivers.
These balloons are launched into what is termed "near space"—the area of Earths atmosphere where there is very little air, but where the remaining amount generates far too much drag for satellites to remain in orbit.
A seasonal vortex in Antartica allows balloons to be recovered very close to their launch site, making it a popular location for balloon-based research.
Due to the low cost of GPS and communications equipment, high altitude ballooning is an emerging hobby.