High-Altitude Balloons

Disclaimer: Copyright infringement not intended.

Context

• China said that US high altitude balloons had flown over its airspace without permission more than 10 times since the beginning of January 2022.

About High-altitude Balloons 

• High-altitude balloons or stratostats are crewed or uncrewed balloons, usually filled with helium or hydrogen, that are released into the stratosphere.
• They generally attain a height between 18 and 37 km above sea level.
• The most common type of high-altitude balloons is 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
• These balloons are launched into what is termed "near space", defined as the area of Earth's atmosphere between the Armstrong limit (18–19 km 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 above sea level), where astrodynamics must take over from aerodynamics in order to maintain flight.

Uses

• Uncrewed high-altitude balloons are used as research balloons, for educational purposes, and by hobbyists. Common uses include meteorology, atmospheric and climate research, collection of imagery from near space, amateur radio applications, and submillimetre astronomy.
• High-altitude balloons have been considered for use in telecommunications^[7]and space tourism.
• High-altitude platform stations have been proposed for applications such as communications relays.
• High-altitude balloons are tempting vehicles for espionage operations, though their use is not known to be very common.

https://indianexpress.com/article/world/china-flew-more-than-10-high-altitude-balloons-chinese-airspace-8442263/