Water Quality Monitor (WQM)


On the International Space Station (ISS), atmospheric humidity condensate and other waste waters will be recycled and treated to produce potable water for use by the crews. Requirements include an on-orbit capability for real-time monitoring of key water quality parameters, such as total organic carbon (TOC), total inorganic carbon, total carbon, pH, and conductivity, to ensure that crew health is protected for consumption of reclaimed water. The Crew Health Care System (CHeCS) for ISS includes a TOC analyzer. For this experiment, an inflight TOC analyzer was developed to demonstrate the technology in microgravity and determine whether the design would meet the analytical requirements for monitoring the quality of ISS reclaimed water. This system also allowed real-time evaluation of the quality of reclaimed potable water.

Shuttle-Mir Missions

Hardware for this experiment consisted of a water sampling kit, a stowage kit and a TOC Analyzer. The sampling kit contained the supplies needed to collect water from the Mir water ports, plastic bags, 25 ml water sample syringes (used to insert samples into the TOC Analyzer), pens for labeling the samples and disinfectant wipes. The stowage kit contained items needed to support the analysis of water samples in the TOC Analyzer, such as data and power cables, test sample syringes and data cards. The crew inserted either test solution or Mir water via syringe into the TOC Analyzer using an access door on the front panel. The crewmember then pushed a button on the instrument's front panel to begin automatic analysis of the sample.

A total of six ground-prepared test samples and two Mir potable water samples were analyzed in flight during the 10-day STS-81 Shuttle mission. Duplicate test samples were analyzed on the ground concurrent with on-orbit analyses. Archived Mir water samples were returned and analyzed for comparison to inflight results.

Analytical performance of the analyzer during the mission was very good. All test sample results, with the exception of a few pH values, were within the prescribed analytical acceptance limits for the experiment. The on-orbit and postflight analytical results for Mir water samples were also in good agreement. Postflight inspection of the TOC analyzer revealed several leaks had occurred inside the containment structure.

The experiment was successful in demonstrating the technology and the hardware, however corrections to the leak problem and minor packaging modifications will need to be made before utilization on the ISS.

None available at this time.

Principal Investigators
Richard L. Sauer, P.E.
NASA/Johnson Space Center

Yuri Sinyak, Ph.D.
Institute of Biomedical Problems (IBMP)

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Page last updated: 07/16/1999