High-altitude balloon

High-altitude balloons or stratostats are usually uncrewed balloons typically filled with helium or hydrogen and released into the stratosphere, generally attaining between 18 and 37 km (11 and 23 mi; 59,000 and 121,000 ft) above sea level. In 2013, a balloon named BS 13-08 reached a record altitude of 53.7 km (33.4 mi; 176,000 ft).^[1]

The most common type of high-altitude balloons are weather balloons. Other purposes include use as a platform for experiments in the upper atmosphere. Modern balloons generally contain electronic equipment such as radio transmitters, cameras, or satellite navigation systems, such as GPS receivers. Hobbyists frequently purchase weather balloons because of their ease of use, low price point, and widespread commoditisation.

These balloons are launched into what is defined as "near space", defined as the area of Earth's atmosphere between the Armstrong limit (18–19 km (11–12 mi) above sea level), where pressure falls to the point that a human being cannot survive without a pressurised suit, and the Kármán line (100 km (62 mi) above sea level^[2]), where astrodynamics must take over from aerodynamics in order to maintain flight.

Due to the low cost of GPS and communications equipment, high-altitude ballooning is a popular hobby, with organizations such as UKHAS assisting the development of payloads.^[3][4]