ITU-R SA.1863 PDF

This Recommendation contains specific guidelines for compatible use of the frequency bands 2 290-2 300 MHz and 2 025-2 120 MHz for manned emergency radiocommunications links. This emergency link is a low-rate/low-power reliable link between a manned spacecraft and the Earth, either through a data relay satellite or directly with a capable earth station and is independent from the spacecraft's telemetry, tracking and command links.