Correction: Change to subject line title to include Product Outage/Anomaly: SARSAT Final Update: Guam 4 LEO Ground Station Offline 


Final Update – Initially, the antenna would not rotate in azimuth. During troubleshooting, it also began experiencing issues with elevation. The vendor dispatched local support and replaced the ACU with a new spare unit, which resolved the elevation issue. However, replacing the azimuth encoder and azimuth motor did not correct the azimuth problem.

The vendor then dispatched an SME to the site. The SME encountered the same issues, including difficulties with antenna initialization. After further inspection, he identified a problem with the tilt axis that impacted azimuth performance. He disassembled and reassembled the tilt axis and also replaced the azimuth drive assembly.
These actions were taken in an effort to fully resolve the issue.


Topic: SARSAT Guam 4 Low Earth Orbit (LEO) Ground Station Offline


Date/Time Issued: March 23, 2026 1545Z


Product(s) or Data Impacted:  SARSAT alert data


Date/Time of Initial Impact:  July 11, 2025 0856Z


Date/Time of Expected End:  March 23, 2026 1300Z


Length of Outage:  255 Days, 4 hours, and 4 minutes.


Details/Specifics of Change: The Guam 4 LEO Ground Station is not sending pass solution data. The Lut Vendor is investigating.


Impact: Minor - Dual satellite tracking capability lost. Distress alert detection/reporting timeliness affected.


Contact for Further Information: USMCC Operations usmcc@noaa.gov at 301-817-4576


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