Stennis Space Center is also the location of a Naval Research Lab, and specifically the Naval Oceanographic Office and Naval Meteorology and Oceanography Command.

https://www.usno.navy.mil/NAVO https://www.public.navy.mil/fltfor/cnmoc/Pages/home.aspx

"CNMOC is focused on providing critical environmental knowledge to the warfighting disciplines of Anti-Submarine Warfare; Naval Special Warfare; Mine Warfare; Intelligence, Surveillance and Reconnaissance; and Fleet Operations (Strike and Expeditionary), as well as to the support areas of Maritime Operations, Aviation Operations, Navigation, Precise Time, and Astrometry."

This is almost certainly some kind of sensor array.