  Next-generation communication technology will be made possible by cooperation
between terrestrial networks with non-terrestrial networks (NTN) comprised of
high-altitude platform stations and satellites. Further, as humanity embarks on
the long road to establish new habitats on other planets, cooperation between
NTN and deep-space networks (DSN) will be necessary. In this regard, we propose
the use of reconfigurable intelligent surfaces (RIS) to improve coordination
between these networks given that RIS perfectly match the size, weight, and
power restrictions of operating in space. A comprehensive framework of
RIS-assisted non-terrestrial and interplanetary communications is presented
that pinpoints challenges, use cases, and open issues. Furthermore, the
performance of RIS-assisted NTN under environmental effects such as solar
scintillation and satellite drag is discussed in light of simulation results.
