The Defense Threat Reduction Agency (DTRA) is seeking a performer to operate and sustain U.S. International Monitoring System (IMS) radionuclide stations, beginning August 2027. The work involves operating, maintaining, and upgrading both particulate and noble gas monitoring systems to meet a 95% authenticated data availability requirement. Performance will occur at various U.S. IMS stations, including those on private, state, or non-federal properties requiring lease arrangements. No budget amount is specified in this sources sought notice, which is for market research only. This notice is not a solicitation, and no bid or submission deadlines are provided.