The U.S. Government is conducting market research to identify sources with the expertise, capabilities, and experience needed for qualification and production of S-Band Radio Frequency Calibration Backplane Assemblies. This is an informational sources sought notice, not an RFP, RFQ, or IFB; responses are voluntary, no funds are available to pay for preparation, and no award is guaranteed. Security clearance level and foreign participation have not been determined, but contractors should anticipate working with teams of military, civilian, national partner, and contract personnel. The notice includes requirements, a technical data package, and a Contractor Capability Survey, and both large and small businesses are encouraged to participate through direct capability responses or joint ventures, teaming, or subcontracting arrangements. No small-business set-aside decision has been made, and the Government will use market research, including demonstrated small-business interest and capability, to determine its acquisition approach.