  We analyze the combined effect of Poynting-Robertson and solar wind drag on
space debris. We derive a model within Cartesian, Gaussian and Hamiltonian
frameworks. We focus on the geosynchronous resonance, although the results can
be easily generalized to any resonance. By numerical and analytical techniques,
we compute the drift in semi-major axis due to Poynting-Robertson and solar
wind drag. After a linear stability analysis of the equilibria, we combine a
careful investigation of the regular, resonant, chaotic behavior of the phase
space with a long-term propagation of a sample of initial conditions. The
results strongly depend on the value of the area-to-mass ratio of the debris,
which might show different dynamical behaviors: temporary capture or escape
from the geosynchronous resonance, as well as temporary capture or escape from
secondary resonances involving the rate of variation of the longitude of the
Sun. Such analysis shows that Poynting-Robertson and solar wind drag must be
taken into account, when looking at the long-term behavior of space debris.
Trapping or escape from the resonance can be used to place the debris in
convenient regions of the phase space.
