  In this article we construct the pressure form on the moduli space of higher
dimensional Margulis spacetimes without cusps and study its properties. We show
that the Margulis spacetimes are infinitesimally determined by their marked
Margulis invariant spectrums. We use it to show that the restrictions of the
pressure form give Riemannian metrics on the constant entropy sections of the
quotient moduli space. We also show that constant entropy sections of the
moduli space with fixed linear part bound convex domains.
