The pressure rise is consistent with a constant leak rate of about 640 mTorr per day. Based on this test, which found no damage to the filter, we expect the flight filter to survive launch without damage. At that time, the internal pressure was still in the 5 microtorr range. We now believe that this pressure rise is due to an undetected leak at the rate of about 2 Torr per day. The instrument was pumped out to about 6 microtorr for testing, and was extensively tested for over 12 hours.
All systems appear to be working correctly.
The camera was then vented to atmosphere and a pressure test was performed on the relief valve, which was shown to operate at about 20 Torr differential pressure. During launch, this will vent through the relief valve, so that the pressure on orbit will be 20 Torr or less when the door is opened. We have previously demonstrated that the filters will not break if the door is opened in this way. The camera was then pumped out to 7 microtorr again and the pumps were removed for the final time. Last week the thermal paint on the radiation plate was touched up and the pump port was closed.