The Kármán line is a widely used threshold, set near 100 kilometers above sea level, that marks the practical edge of space. It is not a physical wall; it is a convention used to separate atmospheric flight from orbital or spaceflight operations. In aerospace engineering, crossing this boundary changes the dominant forces on a vehicle, from air pressure and drag to vacuum, radiation, and reentry heating.
In cyber security, the term matters wherever software and networks control space systems. Launch vehicles, satellites, ground stations, and telemetry links all depend on accurate mission data and reliable command paths as they move across this boundary. Attackers may target those systems by tampering with control software, spoofing signals, or disrupting communications, while defenders use strong authentication, segmented networks, and integrity checks to protect the mission. The Kármán line is therefore a useful operational marker: it reminds engineers that the threat model can change sharply once a system reaches space.