Space Station Lab Flight Test Article Results and Analytical Model Correlations

The International Space Station (ISS) Temperature and Humidity Control/Intermodule Ventilation (THC/IMV) system for the U.S. Lab provides required cooling air for the U.S. Lab and also provides “parasitic” cooling air for Node 1 and its attached elements. This scheme provides cooled air from the Lab THC directly to Node 1 and also to elements attached to Node 1, at different stages of Space Station assembly.

This paper reports on the results of Open Hatch ECLSS/ TCS Tests for International Space Station’s Lab Module. The hardware tested is referred to as proto-flight hardware. Upon satisfactorily passing these Open Hatch and later Closed Hatch, imposed ground based, proto-flight tests, the proto-flight hardware will become flight hardware. The Lab Module is scheduled for launch during late 1999. The particular ECLSS/TCS equipment discussed here are the Temperature Humidity and Control (THC) equipment and Intermodule Ventilation (IMV) equipment. The integrated THC/IMV equipment assembly located between the Lab Module and Node 1 is intended to provide distribution of necessary cooling air capability, CO₂ removal and trace containment control capability. The purpose of the Open Hatch test was to show overall capability of the Lab Module’s THC/IMV system fans and ducting system to meet basic requirements and to: 1) provide detailed flow and pressure drop performance data for individual duct/fan segments and 2) show cabin air velocities are within an acceptable range. The later Closed Hatch testing will show THC/IMV system performance for temperature and humidity control along with removal of heat loads and condensate loads. This paper shows the test results for flow, local velocities, and pressure drop; and correlations with corresponding data from modeled THC and IMV circuits.

A development test of the U.S. Lab and Node 1/attached elements’ integrated THC/IMV ducting system was performed in the summer of 1995. This test included the U.S. Lab’s development level Common Cabin Air Assembly (CCAA), which removes sensible and latent heat from the circulated and ducted cabin air.

Two analytical models for the Development Test level THC/IMV system have been prepared for the Multibranch analytical tool. Flight configuration versions of these models have also been prepared. In each case a pair of analytical models have been prepared. One model with the starboard side CCAA operational and one model with both CCAAs operational. In the latter case the shutoff valve in the crossover supply air ducting is assumed to be closed. The starboard side CCAA then supplies cool air to the Lab’s starboard side supply air branch and the parasitic supply line to Node 1 and the port side CCAA supplies cool air to the Lab’s port side supply air branch.