  In \cite{AminMoc} we defined the Minkowski superspace $SM(4,4\vert \lambda,
\mu)$ as the invariant of the Poincare supergroup of supertransformations,
which is a solution of Killing superequations.
  In the present paper we use formulae of super-Riemannian geometry developed
by V.~P. Akulov and D.~V. Volkov \cite{AkVolk} for calculating a
superconnection and a supercurvature of Minkowski superspace. We show that the
curvature of the Minkowski superspace does not vanish, and the Minkowski
supermetric is the solution of the Einstein superequations, so the
eight-dimensional curved super-Poincare invariant superuniverse $SM(4,4\vert
\lambda, \mu)$ is supported by purely fermionic stress-energy supertensor with
two real parameters $\lambda$, $\mu$, and, moreover, it has non-vanishing
cosmological constant $\Lambda=12/(\lambda^2 -\mu^2)$ defined by these
parameters that could mean a new look at the cosmological constant problem.
