We report new elastic and inelastic cross sections for O( 3 P)+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( 3 P)+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 proportionally lower than predicted by mass-scaling.