Truss S1 or P1 showing location of 3 radiators that are not deployed, 6 Radiator Beam Valve Modules, and an Ammonia Tank Assembly.
Controls: In order to maintain the correct amount of ammonia, at the appropriate temperature and pressure the EATCS employs several control assemblies. First, there is the Ammonia Tank Assembly (ATA). The ATA consists of two ammonia tanks whose pressure is controlled by a Nitrogen Tank Assembly (NTA). The NTA consist of nitrogen under high pressure so that it can efficiently control the pressure of the ammonia in the ATA. Ultimately, the NTA regulates the pressure of the ammonia in the loops. Ammonia’s pressure in the ATA is increased or decreased by regulating how much pressure the NTA exerts on the ATA. This nitrogen pressure moves the ammonia into the loops and keeps it circulating.
Fri, 09 Apr 2010 03:32:40 -0500
STS-131 spacewalkers Rick Mastracchio and Clayton Anderson disconnected ammonia and nitrogen fluid lines from a spent Ammonia Tank Assembly (ATA). The old ATA will be removed from the International Space Station’s starboard truss during the mission's second spacewalk. Mastracchio and Anderson also removed bolts that held the replacement ATA in Discovery’s payload bay, then handed the new assembly to the space station robotic arm, operated by Pilot James P. Dutton Jr. and Mission Specialist Stephanie Wilson. The arm is moving the new ATA to a temporary location on the Quest Airlock External Stowage Platform 2. The spacewalkers also retrieved the Micro-Particles Capture/Space Environment Exposure Device experiment from the Japanese Exposed Facility and will bring it back to Earth. The spacewalk has been under way for two hours, 55 minutes.
Exhibit 11. Ammonia Tank Assembly (ATA)
Exhibit 12. Nitrogen Tank Assembly (NTA)
The Pump Module and the Pump & Control Valve Package also helps to control the flow and pressure of the ammonia in the loops, as well as the temperature of the ammonia. The Pump Module controls these variables by flow control values that allow for combining cool and heated ammonia to maintain an appropriate temperature, pressure, and flow of ammonia in the external loops.
Exhibit 13. Pump Module (PM)
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