AFMC Command News

Researchers explore materials degradation in space

  • Published
  • By Molly Lachance
  • Air Force Office of Scientific Research Public Affairs
ARLINGTON, Va. --  When Space Shuttle Endeavor launched in March, more than 1,000 new materials were onboard to be tested as a part of the sixth Materials International Space Station Experiment, or MISSE-6.

The Air Force Office of Scientific Research initiated MISSE-6 to gain a theoretical understanding of the mechanisms involved in materials degradation. In the low-Earth-orbit environment -- 50-1,240 miles above the Earth's surface -- materials erode more quickly because they are exposed to ultraviolet rays and atomic oxygen, an elemental form of oxygen not found in Earth's atmosphere.

Results from MISSE-6 will provide a better understanding of the durability of various materials in a harsh environment. Knowing which materials can truly be used in space will have important applications in the design of future spacecraft.

MISSE-6 consists of two sample containers -- much like suitcases -- attached to the outside of the International Space Station that are used to test the effects of exposure to space. Each container houses small samples of hundreds of new materials.

Some of the materials selected for MISSE-6 include: an extremely hard, ceramic-like material developed at the University of North Dakota; enzymes and cells encapsulated in silica prepared by UES, Inc.; and spider silk thread from Oxford University.

AFOSR and The Boeing Company assembled and installed the materials into the sample containers before sending them to NASA's Langley Research Center for tests. The Boeing Company is the prime contractor used by NASA to design, develop, integrate, test and deliver the U.S.-built elements of the International Space Station. MISSE-6 A and B are integrated and flown under the direction of the DOD space test program.

On March 22, 2008, an astronaut carried the sample containers outside the shuttle and mounted them to their designated locations on the ISS.

After approximately one year of exposure, another team of astronauts will retrieve the sample containers and take the samples back to Earth. There, researchers will evaluate the materials based on their reaction to atomic oxygen erosion, direct sunlight, radiation and extremes of heat and cold. This will help them determine which materials can withstand the harsh environment of space.

"Making it unique, MISSE-6 is the first of these experiments to test biomaterials," said Lt. Col. Robert Mantz, program manager for the Mathematics, Information and Life Sciences directorate at AFOSR. "It will also focus on active experiments to include shutters, biases placed on samples and real-time data recording."

MISSE-6 is also the first of its kind to connect to space station power, allowing astronauts to respond more quickly, should the experiments encounter any problems. The work required to connect to space station power has laid the groundwork for a data link for MISSE-7.