Environmental Monitoring of Vertical Launch Systems

Sponsored by: Naval Surface Warfare Center – Port Hueneme Division (NSWC-PHD)

Prior to the advent of vertical launch systems (VLS), missiles were fired from fixed ballistic angle canisters, which severely limited the range of the missile without turning the ship. Vertical launch systems allow for 360° launch capabilities and rapid fire of vertically launched missiles. The health of the missiles can be compromised by shock, extreme heat, and humidity. Currently, missile health is determined by periodically transferring the launch canisters to an onshore facility for visual inspection. This is a very time consuming and costly process. This method is also not highly reliable, since it does not reveal any data from environmental events occurring in the canisters. Another drawback to this method is the lack of real-time environmental condition information at critical times such as after a damage event. Since it is difficult to monitor the missile itself, monitoring the environment in the canister where the missile is stored is a viable alternative. Accordingly, AITHER proposed to develop a fiber optic based vertical launch system environmental monitoring system (VLS-EMS) that provided high-speed, real-time environmental data for VLS canisters such as shock events (accelerations) and temperature.

AITHER developed a High Speed – Fiber Optic Interrogation System (HS-FOIS) under a previous research effort sponsored by the Office of Naval Research. The HS-FOIS was used as the interrogation system for this application and has the capability of monitoring hundreds of fiber Bragg grating (FBG) sensors at speeds up to 3 kHz. NSWC-PHD purchased a HS-FOIS system as well as FBG-based low amplitude accelerometers,high amplitude accelerometers, and temperature sensors with non-SBIR funding. AITHER was then awarded a Phase I SBIR contract to investigate the feasibility of increasing the speed of the HS-FOIS from a maximum speed of 3 kHz for one optical channel up to 5 kHz for eight optical channels. Each optical channel has the capability of interrogating up to 20 FBG sensors. New electro-optical hardware components were identified that are capable of reaching the desired sampling speeds. Following the completion of the Phase I effort, NSWC-PHD purchased additional accelerometers and temperature sensors to complete a full system test of the VLS-EMS on the ex-USS PAUL F. FOSTER, a former Spruance Class destroyer outfitted with MK41 VLS canisters that serves as a full-scale test and evaluation platform.