  We report new elastic and inelastic cross sections for O($^3P$)+CO$_2$
scattering at collision energies from 0.03 to 5 eV, of major importance to O
escape from Mars, Venus, and CO$_2$-rich atmospheres. The cross sections were
calculated from first principles using three newly constructed ab-initio
potential energy surfaces correlating to the lowest energy asymptote of the
complex. The surfaces were restricted to a planar geometry with the CO$_2$
molecule assumed to be in linear configuration fixed at equilibrium.
Quantum-mechanical coupled-channel formalism with a large basis set was used to
compute state-to-state integral and differential cross sections for elastic and
inelastic O($^3P$)+CO$_2$ scattering between all pairs of rotational states of
CO$_2$ molecule. The elastic cross sections are 35\% lower at 0.5 eV and more
than 50\% lower at 4+ eV than values commonly used in studies of processes in
upper and middle planetary atmospheres of Mars, Earth, Venus, and CO$_2$-rich
planets. Momentum transfer cross sections, of interest for energy transport,
were found to be lower than predicted by mass-scaling.
