A mechanism of the anomalous increase of the short-circuit current of n(+) -p-p(+) silicon space solar cells under high fluence of the high-energy 10MeV protons or 1Mev electrons is proposed. In distinction to other models this mechanism takes place as a result of the conversion of conductivity type and increased minority carrier lifetime with respect to that of majority carriers. This mechanism occurs in solar cells with deep centers, whose energy level is close to the middle of the band gap.