  In this article we address a problem of determination of light pressure upon
space structures of the complex geometric shape. For the surface element, we
wrote a condition that this element can interact with light only from the front
side, not from the back side. This condition To in the form of series of
Chebyshev polynomials of the first kind. Chebyshev expansion lets us move to
the series of tensors of increasing rank for the problem of determination of
force and moment. We obtained expressions for the fiber method for
determination of light pressure on space structures of complex geometry taking
into account self--shadowing and reflections within the structure. We also give
the expressions for tensor parametrization by the specularity coefficient in
case of specular-diffuse reflection. For these expressions we calculated the
principal moment and force upon two-sided flat solar sail, spherical and
cylindrical bodies, and approximated light pressure upon a perspective space
observatory Millimetron. The proposed expressions can be used in the ballistic
analysis of solar sails and other space objects, which are significantly
affected by the radiation pressure. Also, these results can be used to analyze
the dynamics of movement of large-scale space structures around the center of
gravity under the light pressure.
