  Disagreement in estimations of the observed acceleration of Phobos yields
several theories empirically modifying classical description of motion of the
satellite, but its orbital positions detected by Mars-aimed spacecraft differ
from predictions. It is shown that the satellite's orbital perturbations can be
explained as manifestations of the relativistic time-delay effect ignored in
classical models. So computed limits of Phobos' acceleration essentially exceed
the experimental values. The satellite's expected orbital shift is calculated
for the moment of contact with a landing module of the Phobos-Grunt project;
the shift assessed in kilometers may prevent the mission success. Limits of the
apparent relativistic accelerations are predicted for fast satellites of
Jupiter.
