The hardware onboard a spacecraft gives off a lot of
heat during operation. Since fluids and heat transfer behave differently
in low and micro gravity environments, special equipment must be used
to radiate this excess heat into space safely and efficiently.
To help maintain a suitable and comfortable environment
for the crew and hardware, NASA’s Glenn Research Center is
supporting the Active Thermal Control Systems Project. Glenn was
chosen to support Johnson Space Center (project lead) because of
the center’s expertise in fluid and combustion behavior in
microgravity environments and in composite materials.
Glenn and Johnson have partnered with the Jet Propulsion
Lab and Goddard Space Flight Center on this project. They are also
receiving support from several contractors including Hamilton Sundstrand,
Paragon and Mainstream.
Thermal control systems have existed on all manned spaceflights
and will be required on future lunar and Martian outposts. The thermal
control process consists of three primary elements: heat acquisition,
heat transport and heat rejection. All three elements are being
improved under the current project to reduce the weight, volume
and complexity of current systems in use on the Space Shuttle and
International Space Station. In addition, the future exploration
vehicles and outposts require systems that will last throughout
extended missions.
Glenn is currently developing two new heat exchangers that are more
lightweight and more efficient than previous models. |
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Advanced Composite
Radiator. |
The Advanced Composite Radiator is made
of composite material instead of aluminum, which makes this heat exchanger
very lightweight. Aluminum tubes that carry cooling fluid are carefully
bonded to a composite sheet. (Aluminum is used to reduce the risk
of fluid leakage.) Heat is then transferred from the fluid in the
tubes to the composite material. Finally, the heat is radiated into
space.
Glenn has completed testing to ensure the strength of the bonding
of the composite material. In September 2007, the composite radiator
will be put into an integrated test system at Johnson to verify the
effectiveness of heat transfer in comparison to other devices. |
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The Compact Flash
Evaporative Heat Exchanger uses a fine spray from a unique
atomizer initially designed to remove heat from the electronics
in large supercomputers. The atomizer is a plate containing small
holes that create fine droplets when water is forced through them.
The objective is to evaporate as much liquid as possible as it
hits the hot surface of the heat exchanger. Smaller droplets of
water evaporate faster and significantly increase the effectiveness
of the heat transfer process.
The atomizer (spray plates) for the evaporative heat exchanger is
being tested in a vacuum facility at Glenn. Like the composites, the
atomizer will be sent to Johnson to be added to the integrated test
system at the end of September 2007.
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Compact Flash Evaporative
Heat Exchanger. |
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Thermal control is an essential element of the spacecraft
and outposts inhabited by humans. To ensure the comfort and safety
of the crew and equipment, Glenn is developing two new types of
advanced technology heat exchange systems. These technologies
will reduce the weight and increase the efficiency of thermal control
systems for future exploration missions. |
Contact at NASA Glenn Research Center
Acting Chief, Advanced
Capabilities Project Office: John
K. Lytle
Space Flight Systems Directorate
/ Advanced Flight Projects Office
216-433-3213
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