The Defense Threat Reduction Agency (DTRA) intends to issue a sole source follow on contract to HDTRA121C0057 for the Arms Control Enterprise System (ACES) Operations and Maintenance (O&M) Support to Peraton,Inc. This sole source contract will be issued in accordance with FAR 6.103-1 (DoD Deviation 2026-O0017), Only One Responsible Source and No Other Supplies or Services Will Satisfy Agency Requirements. THIS IS NOT A REQUIREMENT FOR COMPETITIVE PROPOSALS. Interested parties have fifteen (15) days from the date of publication of this notice to submit in writing to the identified point of contact clear and convincing evidence of their qualifications and/or capabilities. Such qualifications and/or capabilities will be used solely for the purpose of determining whether or not to conduct this procurement on a competitive basis. Responses received after fifteen (15) days, with or without the required information, will be considered non-responsive to this notice and will not be considered. A determination by the Government not to conduct this effort as a full-and-open competitive procurement, based upon responses to this notice, is solely within the Government's discretion. The Government will not reimburse for any expense incurred to respond to this notice. Telephonic inquiries will not be accepted.