... Recommendation for the operation of the STIS MAMAs during NCS initial turn-on and cool down: . It is recommended not to turn on the STIS MAMAs until after 100 hours after the NCS initial turn-on, assuming that the valve heaters are shown to be cycling properly and controlling the value temperatures above their leak level. This recommendation may change depending on the final assessment from the CHAMPS Thermal group of the following risk periods. ...