  Non-Gaussian continuous-variable quantum states represent a pivotal resource
in many quantum information protocols. Production of such states can occur
through photonic subtraction process either at the transmitter side prior to
sending a state through the channel, or at the receiver side on receipt of a
state that has traversed the channel. In the context of quantum protocols
implemented over communication channels to and from Low-Earth-Orbit (LEO)
satellites it is unclear what photonic subtraction set-up will provide for the
best performance. In this work we show that for a popular version of
continuous-variable Quantum Key Distribution between terrestrial stations and
LEO satellites, photon subtraction at the transmitter side is the preferred
set-up. Such a result is opposite to that found for fiber-based
implementations. Our results have implications for all future space-based
missions that seek to take advantage of the opportunities offered by
non-Gaussian quantum states.
