  Knowledge of Saturn's axial moment of inertia can provide valuable
information on its internal structure. We suggest that Saturn's angular
momentum may be determined by the Solstice Mission (Cassini XXM) by measuring
Saturn's pole precession rate and the Lense-Thirring acceleration on the
spacecraft, and therefore, put constraints on Saturn's moment of inertia. It is
shown that Saturn's moment of inertia can change up to ~2% due to different
core properties. However, a determination of Saturn's rotation rate is required
to constrain its axial moment of inertia. A change of about seven minutes in
rotation period leads to a similar uncertainty in the moment of inertia value
as different core properties (mass, radius). A determination of Saturn's
angular momentum and rotation period by the Solstice Mission could reveal
important information on Saturn's internal structure, in particular, its core
properties.
