Past Space Station ARS Testing

Testing of ECLSS subsystems and subassemblies for the ISS has been ongoing at NASA's MSFC since 1987. ECLSS development testing has followed a multiphased program that has gradually increased in complexity as the ECLSS design has matured. Each phase accounts for the various redesign and restructuring activities that have occurred during the ISS development. Phase I of the development program, which began in 1987, includes subassembly demonstration, comparative testing, and long-duration...

Chamber Leakage Test

Static leakage tests of the CMS were conducted as part of the overall system checkout. Pretest analysis had indicated that up to 1.81 kg day (4 lb day) of leakage could be tolerated before chamber atmospheric composition control would be compromised. As shown by pretest analysis, when leakage approaches greater than 2.27 kg day (5 lb day), the OGA could maintain only a steady-state oxygen partial pressure of 15.6 volume percent.29 The static leakage test results showed that the chamber leakage...

CDRA Performance Results

The CDRA operated during the test with only the two previously mentioned anomalies. The first involved a valve position error, while the second was a loss of power to a carbon dioxide adsorbent bed heater. As noted earlier, these anomalies were short-lived and did not recur. During the test, the partial pressure of carbon dioxide within the chamber was maintained between 333.3 and 400 Pa (2.5 and 3 mmHg). This was well below the ISSmaximum allowable of 706.6 Pa (5.3 mmHg). Since very little...

Table Of Contents

Past Space Station ARS ISS ARS ISS TEST TEST Test Facility ECLSS Subassembly Integrated ARS Test Control PRETEST ANALYSIS Day Night Power Cycling Oxygen Partial Pressure Metabolic FACILITY AND SUBASSEMBLY PRETEST Chamber Leakage Carbon Dioxide Removal Oxygen Generator INTEGRATED TESTING Test Condition Subassembly Operations Facility Operations Overall Test Operations DISCUSSION OF CDRA Performance MCA Performance 58 59 APPENDIX A CDRA PRETEST SUPPORTING 63 APPENDIX B CMS TEMPERATURE AND...

Oxygen Generator Assembly

The SFWE OGA was operated independently from June 21, 1995, to November 29, 1995, to determine whether it could produce oxygen at the required rate under ISS operating conditions. These conditions included day night power cycling in which the OGA was placed into a standby mode during the dark portion of the orbital cycle and used feedwater produced by the ISS water processor. The new ISS nitrogen interface pressure of 620 kPa 90 psia to 758 kPa 110 psia was also tested. During the test period,...

Trace Contaminant Control Subassembly

The TCCS utilizes activated charcoal adsorption, high temperature catalytic oxidation, and lithium hydroxide LiOH chemisorption to remove trace chemical contaminants and acidic oxidation products from the chamber atmosphere. In this process, air enters the activated charcoal bed to remove high molecular weight contaminants. After the charcoal bed, the process stream splits, with approximately one-third of the flow passing through a recuperative heat exchanger, catalytic reactor, and postsorbent...

Oxygen Partial Pressure Control Using the OGA

During initial test planning, the OGA was to be used to supply oxygen by electrolyzing water. Given that the OGA was limited to producing oxygen at a four-human metabolic equivalent rate and that it would be in normal operations for 59 percent of the time, it became apparent that CMS leakage would be important to maintaining the chamber oxygen partial pressure within specified limits. Oxygen production rate and removal rate would also work together to provide the resulting test system response...

Test Facility Description

The Phase III IART was conducted in the Core Module Simulator CMS , a 175-m3 6,180-ft3 sealed chamber that provides a closed working volume and connections to facility power and consumable resources. Test control, data acquisition and management, and process monitoring capabilities are also provided by the facility. The entire test facility, called the Core Module Integration Facility CMIF , includes the CMS, resource distribution network, and control room. Bench test stands that support...

ECLSS Subassembly Description

System Diagram Pumps With Relief Valves

The IART is designed to test the ISS ARS configuration planned for the U.S. Habitation Module Hab . This hardware complement includes an OGA, CDRA, TCCS, and MCA. Allowance is made for the addition of a Sabatier carbon dioxide reduction assembly as specified by the ISS design. The ARS configuration tested is shown schematically by figure 3.20 A more detailed IART process and instrumentation diagram for the IART is provided by figure 4. Although pressurized oxygen injection was used during the...

Carbon Dioxide Removal Subsystem

DP Dew Point Sensor 0 Sample Port E Pressure Sensor T Temperature Sensor Release Valve Q Selector Valve The CDRA used during the IART was the same unit tested during the Phase IV POST. Several modifications were made to the CDRA before its use in the IART. These modifications included repacking the desiccant beds, installing instrumentation in one desiccant bed and one sorbent bed, removing excess 5A zeolite material from both sorbent beds and replacing the material with glass beads,...

Major Constituent Analyzer

The MCA utilizes a single-focusing, fixed-magnet scanning mass spectrometer to analyze the chamber atmosphere for nitrogen, oxygen, carbon dioxide, methane, hydrogen, and water vapor. Samples are pumped from remote locations in the chamber to the MCA via a sample distribution system. The MCA sample pump first purges the sample line and then introduces a very small portion of the sample into the mass spectrometer via an inlet leak. The sample gas is ionized by an electron beam and the resulting...