New Experiment to Test Super Teflon in Space
Astronaut Patrick G. Forrester, during the second STS-105 extravehicular activity, prepares to work with the Materials International Space Station Experiment 1 and 2(MISSE-1 and 2). The experiment was installed on the outside of the Quest Airlock during the first extravehicular activity (EVA) of the STS-105 mission.
Credit: NASA

Teflon-coated frying pans may scratch easily, but a souped-up version, a nanomaterial 10,000 times more durable than the ordinary non-stick stuff, is headed for the space station to see if it could someday coat the mechanical moving parts of spacecraft.

But first it must prove it can survive ultraviolet radiation, atomic oxygen, extreme temperatures and other space hazards, after blasting off Monday aboard the space shuttle Atlantis for the International Space Station (ISS).

Astronauts intend to install the material outside the space station during one of the mission's planned spacewalks.

The super Teflon could theoretically slide across a surface for more than 62,000 miles (100,000 km) before wearing away, compared to ordinary Teflon that would last just a mile or so. Researchers added fluoride-coated alumina nanoparticles that helped boost the material's strength and durability, even as it retained most of the Teflon's non-stick slipperiness.

"These are low wear, low friction materials that work well in vacuum, and we want to know if they work well in space," said Greg Sawyer, a mechanical and aerospace engineer at the University of Florida. He leads a multi-university effort backed by the U.S. Air Force that designed a whole range of nanocomposite materials for space trials aboard the space station.

Better space-age materials

Sawyer worked with his former mentors at the Rensselaer Polytechnic Institute (RPI) in New York to develop nanocomposite materials for many different space applications. Super Teflon's durability and non-stick character would make it easier for moving parts within spacecraft to move, and require less energy due to less resistance from friction.

Rensselaer researchers also built conductive nanocomposites in collaboration with the U.S. Department of Energy National Renewable Energy Laboratory. One material consists of a tough polymer filled with carbon nanotubes, or tiny cylinders made of carbon that can conduct electricity. The second conductive material involves liquid crystalline polymers, which can resist fires and many industrial chemicals.

"Conductivity experiments look at how materials with conductivity degrade over time," Sawyer told SPACE.com. "With PTSE [Teflon] and those materials you're looking at how long they can provide adequate lubrication."

Another even more futuristic material comes in the form of so-called "chameleon" coatings developed by the Air Force Research Laboratory in Ohio. These adaptive materials can change their coating surfaces based on how much friction or strength is needed.

Space trials are a go

Researchers ensured that all the nanocomposite materials flying aboard the space shuttle Atlantis could first endure vacuum tests on Earth, as a bare minimum requirement for surviving space trials. The team had to scramble in particular to develop the conductive nanocomposites and ready it for launch in less than a week.

"It was an exciting week and we weren't sure if the composites would hold up to the rigorous testing imposed on them to determine if they could even be launched into space," said Linda Schadler, a materials engineer at RPI.

The Teflon study is part of a larger Materials International Space Station Experiment - 7 (MISSE-7) that will expose materials on an outside test bed, where the experiments face intense radiation and temperatures ranging from -40 degrees to 140 degrees F (-40 degrees to 60 degrees C). Atomic oxygen formed by ultraviolet rays splitting oxygen into single atoms also poses a unique space hazard that can erode materials.

Sawyer designed a tribometer that can monitor the friction of the materials such as the super Teflon. The material sample sits on a turntable resembling a record, and stationary pin rests on top of the spinning sample.

"The sample spins under the pin, and during that we can record the forces so we know how the material is behaving," Sawyer explained.

The experimental setup automatically sends data in real-time to the ISS lab, which then forwards the info to university labs on Earth. After all the work that went into getting their materials launched into space, researchers plan on running the space trials for as long as possible.

Ultimately, MISSE experiments - which can be folded up like a suitcase ? can be collected by spacewalking astronauts to be packed up and returned to Earth for waiting scientists.

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