A loss of radio contact with a spacecraft. This can occur with instrument problems or the apparent destruction of a spacecraft, such as the radio blackout experienced when NASA's Mars Climate Orbiter was lost in 1998. Spacecraft also routinely have a radio blackout when passing behind a celestial object, such as a planet, or when they re-enter the atmosphere and the radio waves cannot penetrate the hot ionized gases that create an electromagnetic atmosphere around the vehicle. The space shuttle experiences a radio blackout of about 12 minutes during re-entry, regaining communications with the ground after it slows to about 12 870 kph.
Subjects: Astronomy and Astrophysics.