Abstract
The US Space Shuttle on-orbit waste heat rejection is currently accomplished through a combination of radiators and a Flash Evaporator System (FES). Three of the FES units have been rebuilt to date because of corrosion problems. In addition, the FES has experienced freeze-ups on-orbit.
As part of NASA’s Orbiter Upgrade Program, a Water Membrane Evaporator (WME) is being developed as a replacement for the FES. The WME will use hydrophobic micropore membrane technology to passively control a water liquid/vapor interface. Waste heat acquired from the Orbiter Freon-21 coolant loop will evaporate water at the interface. The water vapor will pass through the membrane and be vented to space. The WME program takes advantage of the recent advances in hydrophobic micropore membrane technology to provide a simpler and more robust heat rejection device than the current FES.
The WME design uses a hydrophobic and hydrophilic membrane layup over 60 rectangular stainless steel Freon-21 tubes in each of 80 small cores to perform the same function as the FES. The mass and volume of the WME design is comparable to that of the FES.
In the present work, the results of membrane performance tests are presented, the membrane physics are explored, and a membrane performance prediction is developed. The WME design is described in detail and the predicted performance of the WME design is compared to that of the FES.
Extravehicular Mobility Unit (EMU)/International Space Station (ISS) Coolant Loop Failure and Recovery