Building on more than a decade of data from International Space Station (ISS) research, NASA is expanding its materials science research by flying an experiment on the U.S. Air Force X-37B space plane, according to a press release.

By flying the Materials Exposure and Technology Innovation in Space (METIS) investigation on the X-37B, materials scientists have the opportunity to expose almost 100 different materials samples to the space environment for more than 200 days. METIS is building on data acquired during the Materials on International Space Station Experiment (MISSE), which flew more than 4,000 samples in space from 2001 to 2013.

"By exposing materials to space and returning the samples to Earth, we gain valuable data about how the materials hold up in the environment in which they will have to operate," said Miria Finckenor, the co-investigator on the MISSE experiment and principal investigator for METIS at NASA's Marshall Space Flight Center in Huntsville, Ala, according to the press release. "Spacecraft designers can use this information to choose the best material for specific applications, such as thermal protection or antennas or any other space hardware."

But what exactly will the plane do once it leaves Earth? "Most of the X-37B's payloads and specific activities are classified, so it's not entirely clear what the space plane will be doing once it leaves Earth Wednesday," according to Space.com. "This secrecy has led to some speculation that the vehicle might be some sort of space weapon, but Air Force officials have repeatedly refuted that notion, saying X-37B flights simply test a variety of new space technologies."

The Air Force confirmed that the Hall thruster that will fly on the X-37B experiment is a modified version of the units that have propelled SMC's first three Advanced Extremely High Frequency military communications spacecraft. The craft will also test LightSail, a solar sailing satellite from the CubeSat program.