Urine Monitoring System (UMS) - 07.19.17

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ISS Science for Everyone

Science Objectives for Everyone
The Urine Monitoring System (UMS) is a system designed to collect an individual crew member's urine void, gently separate liquid from air in that void, accurately measure the liquid volume of the urine, allow for void sample acquisition, and to then discharge the remaining urine into the Waste and Hygiene Compartment (WHC) on board the International Space Station (ISS).
Science Results for Everyone During Increment 27/28, an attempt at checking the functionality of the UMS was initiated. The checkout was not completed due to an anomaly with the Waste & Hygiene Compartment (WHC). A second attempt at a checkout was also unsuccessful due to a UMS software error. A third attempt at a checkout (in Increment 29/30) was aborted due to suspicion of a grounding issue within UMS which was later confirmed during an on-orbit conductivity test. The UMS was subsequently returned to the ground on Space X-1 during Increment 33 along with the limited number of samples that were obtained during the attempted checkout. Currently the UMS is being analyzed by engineering teams to determine the extent of re-design and refurbishment required to attain the intended functionality. Following that ground analysis, NASA will make a determination as to whether it will be re-flown to ISS.  

The following content was provided by Mark S. Clarke, Ph.D., and is maintained in a database by the ISS Program Science Office.
Facility Details


Facility Manager(s)
Mark S. Clarke, Ph.D., University of Houston/JSC Space Center, Houston, TX, United States

Facility Representative(s)
Information Pending

NASA Johnson Space Center, Human Research Program, Houston, TX, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

ISS Expedition Duration
September 2010 - May 2012; September 2012 - March 2013

Expeditions Assigned

Previous Missions
The UMS is a successor design to the previous Space Shuttle Urine Monitoring System, which flew on seven Shuttle flights after its initial development in 1979.


  • Retired/Returned/Disposed
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    Facility Description

    Facility Overview

    The Urine Monitoring System (UMS) is a successor design to a previous Space Shuttle system (also named UMS) and is intended to resolve anomalies such as: liquid carry-over, inaccurate void volume measurements, and cross contamination between void samples.
    In the future, the UMS may be used to facilitate non-invasive methods for monitoring crew health, evaluation of countermeasures, and implementation of a variety of biomedical research protocols on future exploration missions.
    During Increment 27/28, the crew attempted to perform the first functional validation of the UMS aboard the ISS, but that activity was aborted due to anomalies. Subsequent efforts to complete the validation in that increment and the next were unsuccessful, so the hardware was returned to Earth on Space X-1 for further investigation and potential refurbishment.
    The ISS Urine Monitoring System (UMS) is an upgrade to the previous Space Shuttle system. The UMS is capable of collecting and accurately measuring void volume, separating urine from air in the void, and allowing acquisition of individual, uncontaminated urine samples from ISS crew members, with samples being collected using frozen urine syringes and/or ambient preserved urine syringes containing a mixture of thymol and thimerosal. The UMS is designed to operate in conjunction with the airflow of the Waste and Hygiene Compartment (WHC) of the ISS; the hardware consists of a laptop computer and a mechanical module. The laptop serves as the primary crew interface, while the mechanical module contains a liquid/air separator, a motor, solenoid valves, fluid plumbing and the sample acquisition port. While deployed, the mechanical module resides in the Waste and Hygiene Compartment in Node 3 of the ISS.
    A safe, accurate and reliable means of obtaining representative urine samples and total void volume measurements from the ISS crew members is essential to human research. Use of the UMS substantially reduces the launch mass and volume of consumables required for urine collection, eliminates the need for on-orbit stowage and disposal of large quantities of leftover urine, avoids the loss of urine to the water reclamation system when urine samples are required, resolves gender issues with the current system, and provides ease of operation.
    The UMS also facilitates the performance of future investigations requiring urine sample collection by automatically measuring void volumes which is required to enable future real-time analysis of samples. Operational deployment of the UMS will reduce the number of samples requiring return to Earth for analysis and provides more timely results to investigators along with feedback to medical personnel regarding crew health.
    During the equipment checkout, the UMS hardware is functionally tested to determine its efficacy at eliminating (1) liquid carry-over between cycles, (2) inaccurate void volume measurements, and  (3) cross contamination between void samples. Samples obtained as part of the checkout will be returned to the ground for postflight analysis. Once proper functionality is verified, the UMS will be available for use by experiments that require urine collection and determination of urine volume. Results concerning accurate void volume measurements will be quickly analyzed via downlink of log files. Analysis of liquid carry-over and cross-contamination will be determined by ground analysis of samples returned from the checkout. Results of the ground analysis will be communicated to the PI teams already using UMS for sample collection for their information and evaluation. 
    One crew member acts as both operator and subject to perform the following tasks:
    Functional validation is intended to validate accurate individual void volume measurements across the different calibration ranges used by the UMS. The operator injects each pre-filled Validation Syringe containing a non-toxic urine simulant or distilled water into the ISS UMS urinal hose, simulating various urination volumes, as directed by the UMS software. Depending on the sequence being performed, a singe Validation Syringe may be injected into UMS, or a set of Validation Syringes may be injected. During processing of the samples, the operator acquires samples for post-flight analysis to determine carryover volumes and cross-contamination. A total of 37 Validation Syringes are utilized for the evaluation. Two additional Validation Syringes are flown to serve as controls.
    Nominal usage will begin after successful validation. For nominal use, the crew voids into the UMS which allows for both void volume measurement and collection of urine samples for an experiment.

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    Facility Operations

    • The crew installs and activates the ISS UMS. One crew member acts as both operator and subject to perform UMS tasks.
    • The crew member performs a functional evaluation using a set of pre-measured Validation Syringes with known volumes, known density, and known concentrations of urea.
    • The log files from this evaluation are downlinked to ground for analysis. When satisfactory results are obtained from the ground analysis of the log files, the UMS will replace Urine Collection Devices as the primary means of urine sample collection. 
    • Samples from the functional evaluation return to ground for additional analysis including determination of sample cross-contamination using urea as a tracer.

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    Decadal Survey Recommendations

    Information Pending

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    Results/More Information

    Information Pending

    Results Publications

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    Ground Based Results Publications

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    ISS Patents

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    Related Publications

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    Related Websites

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    image Photograph of the mechanical module portion of the Urine Monitoring System (UMS). Image courtesy of the Johnson Space Center, Human Research Program, Houston, TX
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