Following the previous news on the Sentinel-1B anomaly that occurred on 23 December 2021, very detailed investigations related to the satellite power system’s affected unit have continued over the past weeks.
One potential failure scenario could be linked to a leakage of a ceramic capacitor which is part of the main and redundant regulators of the 28V power regulated bus (the bus that supplies power to the SAR electronics subsystem). Such scenario has been qualified by experts as possible. No conclusions have been drawn yet on the clear identification of the anomaly.
In parallel to the investigations, satellite system level analyses have been conducted, with the aim to perform new recovery attempts of the power unit. Using various commanding strategies, several attempts consisting in switching ON the prime and redundant regulators have been executed, some of them requiring substantial work and the preparation of new operational procedures.
In one of the many attempts to switch ON the prime regulator, the status of the regulator remained ON for 4.4 seconds and was then reverted autonomously to OFF, as observed through the related telemetry. This was the first time this change of status was observed since the start of the recovery attempts in early January 2022. This behaviour could indicate that the prime regulator features a degradation, but not necessarily a permanent failure.
Further tests will be performed over the next days and weeks, with the objective to understand the observed behaviour and potentially identify new recovery actions of the 28V regulated power bus. Some of the attempts will be executed by turning ON or OFF heaters hence varying the power supply temperature, this could influence the behaviour of the regulators.
The conclusions of the Anomaly Review Board are expected towards end of May 2022.
The satellite remains under control, the thermal control system works properly, regular orbit control manoeuvres are routinely performed.
Sentinel-1 users should still assume a long-term unavailability of data provision (several months). It is however too early to consider a permanent unavailability of Sentinel-1B.
We apologize for the inconvenience caused.