The DNA molecules are stable but easily fragmented by ionization radiation, which challenges DNA integrity in searching for evidence for extraterrestrial life on icy satellites. The objective was to estimate the highest value of the attenuation effect of freezing temperature on the efficacy of gamma-radiation in fragmenting dsDNA. A bacterial 16S rRNA gene inserted in a vector as a lyophilized crude cell lysate was irradiated (⁶⁰Co) under the liquid nitrogen conditions (-195.8^oC). The outcome was tested in a specific PCR, generating the MAIN (~600bp) as well as EXTRA “mis-primed” small-sized (~70bp) amplicons. At the ambient temperature, the main PCR product entirely disappeared upon the doze 7.5kGy while at -195.8^oC, it withstood ~750kGy (~100 times difference). Vise-verse, the EXTRA short amplicon reached the maximum outcome at the dose ~400kGy and continued to persist until the tested dose 840kGy. By extrapolation, the given product could be generated upon irradiating target DNA at a dose of more than 1mGy. Such a find opens a chance (and time window of more than 25 years) to pick up freshly flushed out sub-ice-ocean microbes/DNA and get frozen as inclusions in water matrices on the Jovian Europa to verify the extraterrestrial life.