Urine Processor Assembly Hardware Improvements (UPA) - 05.30.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Water is a precious and limited resource in space, so orbiting crew members recycle it whenever possible, including recycling their own urine. Urine Processor Assembly Hardware Improvements Investigation (UPA) tests improvements to the urine processing equipment on the International Space Station. Results improve the hardware’s design, including changes to materials, to prevent equipment failures on current and future space missions.
Science Results for Everyone
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Experiment Details


Principal Investigator(s)

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Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

Research Benefits
Space Exploration

ISS Expedition Duration
March 2015 - September 2015

Expeditions Assigned

Previous Missions
All 3 flight units are currently installed and operating on-orbit in the Urine Processor Assembly, which extracts water from crew urine via vacuum distillation. This water, combined with recaptured water from the crew cabin heat exchanger, undergoes further treatment in the Water Processor Assembly and ultimately becomes crew drinking water as part of the potable water system.

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Experiment Description

Research Overview

  • Current UPA hardware has experienced on-orbit failures due to both hardware complexity and a harsh operating environment, materials-wise.
  • Research focuses on improving robustness of design, including both design simplification and selection of materials better suited for the UPA operating environment.
  • Research results help to improve hardware reliability for both current International Space Station (ISS) Environmental Control and Life Support System ECLSS hardware and hardware designs for future exploration missions.
  • Distillation Assembly (DA) dimensions are approximately 30” x 18.5” x 16.6” and its mass is approximately 166.6 lbs. The primary purpose of the DA is to recover water from crew urine using a vacuum distillation process.
  • Pressure Control and Pump Assembly (PCPA) dimensions are approximately 26” x 16.5” x 10.4” and its mass is approximately 98.7 lbs.  The PCPA’s primary purpose is to provide a vacuum source to the Distillation Assembly (DA).
  • Fluids Control and Pump Assembly (FCPA) dimensions are approximately 27.1” x 16.5” x 9.9” and its mass is approximately 100.5 lbs.  The FCPA’s purpose is to pump crew urine to the DA and remove both concentrated brine waste and product water from the DA once the vacuum distillation process is completed.

Research focuses on improving reliability of Urine Processor Assembly components, with applicability to both the current UPA installation on ISS and future exploration missions. Specific design improvements, assuming successful designs can be implemented, include: 1. DA compressor and centrifuge bearings – finding bearing material that can survive the harsh, acidic environment in the DA has been difficult. It is hoped that a new bearing material, Nitinol 60, extends running life, compared with the current Cronidur 30 bearings. 2. DA compressor gears – new gear material (possibly ceramic) could simplify manufacturing process for matched gear sets and significantly extend the life of the gears (and DA). 3. DA liquid level sensor – redesign necessary, as the current sensor produces false high liquid level readings, requiring disabling of certain UPA software functions. 4. DA O-ring drive belt – current design is one of the DA limited life items. Redesign to a more robust Gates-type belt could significantly extend the life of the DA. 6. PCPA/FCPA Harmonic Drive Train – current harmonic drive design requires precision alignment to prevent premature failure (at least one FCPA has failed on-orbit due to misalignment). Redesign could both simplify assembly of the units and enhance FCPA/PCPA life and reliability. 7. FCPA Valve Design – current design has a long history of failing leak testing following final assembly, requiring many instances of tear-down and rework. The primary goal of the redesign will be to improve success in final assembly leak testing and improve reliability on-orbit, particularly for long-duration missions. Marshall Space Flight Center is collaborating with Glenn Research Center on the demo DA compressor/centrifuge bearings, as well as the compressor gears.

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Space Applications
The Urine Processor Assembly on the ISS recycles urine, but it has failed in the past, in part because of the equipment’s complexity and in part because of the harsh conditions in which it works. The UPA investigation improves the reliability of regenerative water systems, benefiting current and future space exploration.

Earth Applications
The UPA investigation studies new compressor and centrifuge bearings, gear material, valves, liquid sensors and seals, and other components of the ISS water recovery system. Results help development of better, more reliable lightweight, portable waste processing equipment used on Earth, including for emergency use or in areas with poor sanitation or unsafe drinking water.

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Operational Requirements and Protocols
The demo units are installed and operate just like the flight units. No new procedures or crew training are required
The demo units are installed and operate just like the flight units. No new procedures or crew training are required

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Decadal Survey Recommendations

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Results/More Information

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Related Websites

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image UPA Distillation Assembly (DA). (NASA Image)
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image Fluids Control and Pump Assembly (FCPA). (NASA Image)
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image Pressure Control and Pump Assembly (PCPA). (NASA Image)
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