ISS Daily Summary Report – 05/09/13

New Status: 
This afternoon the crew noticed white flakes floating outside on the port side of the vehicle.   At the same time ground teams noticed a drop in the 2B Photovoltaic Thermal Control System (PVTCS) ammonia pressure, indicating an external ammonia leak.  The 2B PVTCS has had a known slow leak for several months, but today the leak rate increased.  Without the PVTCS providing cooling to the Electrical Power System, channel 2B will be powered down.   Prior to the channel shutdown, the 2B loads will be transferred to channel 2A, and no impact to powered equipment is expected.  Ground teams are assessing the forward plan to locate the leak.  The crew and the ISS vehicle are in a safe configuration.