  Twenty years of gravity observations from various satellite missions have
provided unique data about mass redistribution processes in the Earth system.
This paper studies the benefit of enhanced electrostatic and novel optical
accelerometers and gradiometers for the future gravimetry missions. One of the
limiting factors in the current space gravimetry missions is the drift of the
Electrostatic Accelerometers (EA). This study focuses on the modeling of
enhanced EAs with laser-interferometric readout, so called 'optical
accelerometers', and on evaluating their performance for gravity field recovery
in future satellite missions. In this paper, we simulate gravimetry missions in
multiple scopes, applying the various software modules for satellite dynamics
integration, accelerometer (ACC) and gradiometer simulation and gravity field
recovery. The total noise budget of the modeled enhanced Electrostatic and
optical ACCs show a similar sensitivity as the ACC concepts from other research
groups. Parametrization w.r.t. ACCs test mass (TM) weight and the gap between
the test mass and surrounding electrode housing confirmed previously known
results that an ACC with a heavier TM and larger gap will have better
performance. Our results suggest that the anticipated gain of novel ACCs might
at some point be potentially limited by noise from the inter-satellite laser
ranging interferometry. In order to present the advantage of the novel sensors,
time-variable background models and associated aliasing errors were not
considered in our simulations. Utilization of enhanced EA and optical ACC show
a significant improvement of accuracy w.r.t. current GRACE-like EA. Also, their
benefit in double satellite pairs in a so called 'Bender' constellations as
well as in the combination of low-low satellite-to-satellite tracking with
cross-track gradiometry has been investigated.
