  Recent advances in cold atom interferometry have cleared the path for space
applications of quantum inertial sensors, whose level of stability is expected
to increase dramatically with the longer interrogation times accessible in
space. In this study, a comprehensive in-orbit model is developed for a
Mach-Zehnder-type cold-atom accelerometer. Performance tests are realized under
different assumptions, and the impact of various sources of errors on
instrument stability is evaluated. Current and future advances for space-based
atom interferometry are discussed, and their impact on the performance of
quantum sensors on-board satellite gravity missions is investigated in three
different scenarios: state-of-the-art scenario, near-future (between the next 5
and 10 years) and far-future scenarios (between the next 10 to 20 years). We
show that one can achieve a sensitivity level close to 5E-10 with the current
state-of-the-art technology. We also estimate that in the near and far-future,
atom interferometry in space is expected to achieve sensitivity levels of 1E-11
and 1E-12, respectively. A roadmap for improvements in atom interferometry is
provided that would maximize the performance of future CAI accelerometers,
considering their technical capabilities. Finally, the possibility and
challenges of having ultra-sensitive atom interferometry in space for future
space missions are discussed.
