The U.S. Air Force is seeking industry input and capabilities for the Advanced Radar Threat System (ARTS) Variant 3 (V3) Variable Aperture Digital Radar (VADR) Third-Party Software initiative, focused on software for advanced threat emulation and digital AESA radar systems. The effort is planned under the Consortium for Command, Control, and Communications in Cyberspace (C5) Other Transaction Authority (OTA) agreement, requiring C5 membership for awards and proposing one-third cost-sharing for traditional DoW vendors acting as prime performers. Key technical requirements include radar/DSP and EW integration, RTOS and modern C++ software updates, C2/VAPP interface development, AESA beam/power management, zero-trust communications with mTLS, MBSE using Cameo/SysML, DevSecOps/cloud CI/CD, and AI-assisted development controls including SBOM, HITL, and SAST/DAST. Desired differentiators include advanced digital twin/closed-loop SIL/HIL emulation, AI/ML for sensor fusion and cognitive EW, predictive maintenance, and specialized radar development/analysis ecosystems. The program anticipates releasing a C5 request for white papers as early as November 2026 and an estimated award around June 2027, with security requirements including active clearance for subscale threat system access and a desired posture up to TS/SAP/SCI.