International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Guided Weapons Evaluation Facility (GWEF) at Eglin Air Force Base is the Air Force’s premiere munitions hardware-in-the-loop (HITL) simulation facility. HITL simulation testing is a ground based tool used to evaluate the performance of a weapon system at a fraction of the cost of free flight testing. The weapon system is stimulated in a laboratory setting with the electromagnetic environment and physical motion it would experience in an operational setting. The system’s responses to that environment are measured to provide various measures of performance including target tracking ability and miss distance. Electrical interfaces are required in order to control the weapon’s guidance system and to receive and inject signals from the HITL simulation computer system to the weapon under test. These interfaces are usually developed using external control circuits and copper cabling to the guidance unit. The GWEF had a requirement to develop a missile interface with no external copper wires or antennas to support a unique test configuration. The requirement led to the development of a Fiber Optic Telemetry (FOTM) package which would be contained completely within the missile body cavity. The constraints on the FOTM design were considerable. Lack of a suitable commercial off-the-shelf fiber optic telemetry package led to the eventual in house design and fabrication of the FOTM. This paper describes the requirements, design constraints and results achieved in the FOTM design. Although not classical telemetry it does share similarities with conventional telemetry units used for open air weapons testing including size constraints, data rates and thermal considerations.