Elaborating on TDRSS a little bit - the ISS has allotments on both S- and Ku-band transponders (there are several per satellite) and hands off between satellite

Elaborating on TDRSS a little bit - the ISS has allotments on both S- and Ku-band transponders (there are several per satellite) and hands off between satellites (TDRSS is geostationary) as it orbits, it's rare that another TDRSS customer has something important enough going on that the ISS gets no allocation at all for more than an orbit. IMHO, the real application for laser communications is for high bandwidth inter-satellite links.