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The AN/SPQ-11 Cobra Judy was a PESA radar found on the USNS Observation Island (T-AGM-23) missile range instrumentation ship.

Cobra Judy Phased Array.jpg
Close-up of the front of Cobra Judy radar, 1983.
Country of originUnited States
No. built1
TypePassive electronically scanned array radar
Frequency2900-3100 MHz (E\F band)
Aft view of the USNS Observation Island showing the location of the Cobra Judy array.

It was used for space tracking, ballistic missiles tracking and other instrumentation. Cobra Judy was the sea component of the COBRA program[clarification needed] for monitoring missile launches and outer space. Cobra Judy was replaced by the Cobra Judy Replacement (CJR) in April 2014.



The Cobra Judy Platform, USNS Observation Island was taken out of service and stricken from the Naval Vessel Register March 31, 2014.[1] On 31 March 2014, the Cobra Judy Replacement program, aboard USNS Howard O. Lorenzen (T-AGM-25) reached initial operational capability (IOC). According to the Naval Sea Systems Command (NAVSEA), the U.S. Air Force also assumed operational and sustainment responsibilities for the ship.[2]

See alsoEdit


  1. ^ "USNS OBSERVATION ISLAND (T-AGM 23)". Naval Vessel Register. Retrieved 2 March 2012.
  2. ^ "Cobra Judy Replacement Achieves Initial Operational Capability". 1 May 2014. No. NNS140501-26. Retrieved 8 May 2014.

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