The onus for Spectrum management lies with ITU. What little I know - Space communications (as against Satellite communication) are allocated frequencies out of the S, X bands. Other bands may be allocated too - the ITU Space Service document was unavailable/pay-walled
What I'm curious about
- Are space communication frequencies allocated per-mission, or per-agency?
- If allocation is per-mission, are the frequencies recycled after the mission is over? E.g. Giotto
- What is the rationale behind the allocation of micro-wave bands to space communication? Instead of, for instance, HF/VHF why are some of the micro-wave bands used? Is it merely a matter of convenient antennas, or is there more to it?