Annealing of radiation damage in space must be given serious consideration because of the low particle fluxes and long irradiation times. The problem of simultaneous production and disappearance of atomic displacements is analyzed for the cases of first- and second-order annealing reactions. By means of a simple jump ev.frequency formula it is concluded that the effective activation energies are reduced by 0.3 A pertinent effect is found in the annealing data on n-type germanium.