  A model of an accelerated expansion of the Crab Nebula powered by the
spinning-down Crab pulsar is proposed, in which time dependence of the
acceleration is connected with evolution of pulsar luminosity. Using recent
observational data, we derive estimates of the Crab neutron-star moment of
inertia. Correlations between the neutron star moment of inertia and its mass
and radius allow for rough estimates of the Crab neutron-star radius and mass.
In contrast to the previously used constant-acceleration approximation, even
for the expanding nebula mass ~7 M_sun results obtained within our model do not
stay in conflict with the modern stiff equations of state of dense matter.
