  It is well known that interstellar travel is bounded by the finite speed of
light, but on very large scales any rocketeer would also need to consider the
influence of cosmological expansion on their journey. This paper examines
accelerated journeys within the framework of Friedmann-
Lemaitre-Robertson-Walker universes, illustrating how the duration of a fixed
acceleration sharply divides exploration over interstellar and intergalactic
distances. Furthermore, we show how the universal expansion increases the
difficulty of intergalactic navigation, with small uncertainties in
cosmological parameters resulting in significantly large deviations. This paper
also shows that, contrary to simplistic ideas, the motion of any rocketeer is
indistinguishable from Newtonian gravity if the acceleration is kept small.
