Special missions aircraft. Special missions adaptions based on the C-135 airframe. Originally developed as EC-135 command post for the B-52 nuclear bomber fleet. RC-135U, RC-135V Rivet Joint and RC-135W signals intelligence variants with automatic ELINT emitter locator system. RC-135V and RC-135W with nose featuring further sensor. TC-135W crew trainig version. RC-135S Cobra Ball for balistic missile launch detection. The US Air Force is re-engining its RC-135s with CFM engines.