International Space Station Atmosphere Control and Supply, Atmosphere Revitalization, and Water Recovery and Management Subsystem - Verification for Node 1

ABSTRACT The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the nominal operation of the Node 1 ACS, AR, and WRM design and detailed Element Verification methodologies utilized during the Qualification phase for Node 1. INTRODUCTION Node 1 flew to ISS on Flight 2A. It was the first module of the United States On-Orbit Segment (USOS) that was launched to ISS. The Node 1 ISS ECLS design featured limited ECLS capability. The main purpose of Node 1 was to provide internal storage by providing four stowage rack locations within the module and to allow docking of multiple modules and a truss segment to it. Of the five Node 1 ECLS subsystems this paper will only address the nominal operation of the ACS, AR, and WRM subsystems. The nominal operation of the Node 1 ACS, AR, and WRM subsystems capabilities can be subdivided into their sub-allocated functions. The Node 1 ACS consists of: 1) a cabin pressure sensor for monitoring total pressure in the Node 1 cabin, 2) lines for routing low-pressure oxygen and nitrogen, 3) Joint Airlock Depressurization Pump Assembly (DPA) outlet line, 4) lines for routing high-pressure oxygen and nitrogen, and 6) manual pressure equalization valves to reduce the pressure differential across the hatch prior to opening the hatch. The Node 1 AR consists of sample lines for routing air samples to the Major Constituent Analyzer (MCA) in the U.S. Laboratory Module or in Node 3. The Node 1 WRM consists of: 1) lines for routing excess Space Shuttle Fuel Cell water or Regen- erative ECLS Water Processor Assembly (WPA) potable water and 2) lines for routing waste water, i.e. condensate from the USOS condensing heat exchangers and waste water from the Extravehicular Activity (EVA) space suits. The Verification of the ISS hardware is accomplished using a building block process. Verification starts at the Component Level and progresses until the Element Level Verification is complete. The primary objective of the Qualification Verification program is to ensure that the subsystems meet the section three requirements in the Prime Item Development Specifications (PIDS). The PIDS dictates whether a section three requirement is verified by test, analysis, inspection, and/or demonstration, as documented in section four of the PIDS. Node 1 is a Protoflight Test Article since no Element Qualification Test Article exists. Therefore, no additional ground testing or evaluations can be performed on Node 1 after it has been installed into the Space Shuttle Payload Bay and launched to ISS. Node 1 is shown in Figure 1 during processing at Kennedy Space Center (KSC) and in flight during the Flight 2A series of Flights (i.e., Flights 2A, 2A.1, 2A.2a, and 2A.2b).