Test System for Simulation of ISS JEMS Module Fluid Loop

ACT designed, fabricated and tested a Fluid Control Unit (FCU) for NASA to simulate a thermal fluid loop using FC-72 for heat rejection onboard the International Space Station (ISS). The FCU is designed to provide FC-72 volume flow, pressure and heat rejection for ground testing of instruments destined for the JEMS module on the ISS. To date, ACT has delivered two FCU’s to NASA in support of the CATS and CREAM instruments.  The user interface enables control of fluid flow, differential pressure and temperature while logging these values. The design includes 40 micron filters, automated valves, vacuum pump and an accumulator. The vacuum pump and accumulator allow the user to evacuate and charge the instrument. The Fluid Control Units are fabricated using high quality materials and meet and exceed the cleanliness requirements of ISO 14952-2:2003.  Capabilities include:

  • Pump fluid (Fluorinert™ FC-72) at varying flow rates up to 3 GPM at 225 psi (11 liter/min at 1.5 MPa).
  • Maintain fluid inlet temperature at a user-specified value within 1°C by rejecting heat to an air-cooled vapor compression system or providing heat using an electric heater.
  • Maintain system pressure at a user-controlled setting.
  • Record and display several system parameters, such as pressures, temperatures, and flow rates.  This could be done using the on-board data logger or by connecting a laptop.
  • Pull a rough vacuum and charge the instrumentation system.
  • Purge the system with Nitrogen and collect purged fluid in the accumulator.
  • Provide a port and functionality necessary for fluid sampling.
  • Be the brightest object in the laboratory (FCU color scheme selected by customer).

ACT communicated regularly with our customer throughout the design and fabrication of the FCU to ensure the unit met their needs.  Prior to shipping, testing of the FCU demonstrated that the unit met all of the customer’s specifications.  Test results were included with the FCU manual that was delivered with the unit.  Two FCU’s has been operating at our customer’s facility for nearly a year now.


Figure 1. Two Views of the Accumulator Test Rig.

Figure 2. ACT’s OCO-3 Fluid Control Unit in service during thermal vacuum testing of the Orbiting Carbon Observatory-3 payload at the Jet Propulsion Laboratory

Figure 2. ACT’s OCO-3 Fluid Control Unit in service during thermal vacuum testing of the Orbiting Carbon Observatory-3 payload at the Jet Propulsion Laboratory

More recently, ACT designed, fabricated and tested a second Fluid Control Unit for the NASA Jet Propulsion Laboratory that was used for ground testing of the Orbiting Carbon Observatory 3 (OCO-3).   OCO-3 was built using the spare OCO-2 instrument and will be installed at the International Space Station (ISS). More info on the mission here: https://science.nasa.gov/missions/oco-3.

The OCO-3 FCU was constructed to provide precisely metered flow at a stable temperature, while measuring and recording flow rate, fluid pressures, and fluid temperatures. The system has an integrated membrane contactor which allows for dissolved gases to be removed from the fluid without draining. This is useful since oxygen readily dissolves in the fluorinated working fluid. Also included in the system is a bellows type accumulator which allows for pressurization of the working fluid without direct contact between any gases and the working fluid.  Figure 2 shows ACT’s FCU unit during thermal ground testing at JPL.

If you are interested in learning more, please contact ACT today.

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