What kind of telecommunication systems do astronauts use in space?

Question

What kind of telecommunication systems do the astronauts use in space? I ask about both earth-to-space and space-to-space.

Answer 1

It varies on every mission, but on the Space Shuttle, NASA has compiled an impressive list of the different communication technologies they use for different purposes.

Pretty much all of these are various variations on radio or microwave communications (the S-band and Ku-band). UHF is used as a backup, especially for EVAs.