At 15:25, an alarm was issued due to the lack of water in the water tank at Yend. The failure of one water supply pump was the cause of the alarm.
Two pumps were used alternatively to supply water to the water tank. However, after switching to the broken pump, the alarm sounded because the water supply to the water tank was stopped.
Currently, we made the water supply system not switch to the faulty pump, and a temporary water pump was added.
The water supply to the cryocooler system is stable.
Attached are trend graphs of the temperatures in the compressors of the cryocooler and Q-mass in the EYC.
The temperatures in the compressors temporarily rose due to the cooling water outage, but have now returned to normal values.
It was also confirmed that there was no change in the partial pressure of residual gas in the EYC after the cooling water was stopped.
Yea and Yer compressors stopped due to cooling water problems. Restarted after cooling water was restored.
P-53, P-54, and P-55 compressors continued operation, but alarms were displayed, so compressors were temporarily stopped and restarted in order to reset the displays.
As we were worried, the temp of EY 50K REFARM HEAD started increasing again because of the violation of the naive condition of cooling.
The temperature increases at EY 50K REFARM HEAD seemed to stop and start decreasing.
The outer shields' temperatures seemed to be below 157K (H2O outgassing temperature) even after one of the cryocoolers for the payload was off. On the other hand, the temperatures were over 157K if the cryocoolers for the payloads were not operated.
