View from the International Space Station of the SpaceX Dragon spacecraft as the robotic arm moves Dragon into place for attachment to the station May 25, 2012. Credit: NASA

(Phys.org) —He described it as "snow white." But NASA astronaut Don Pettit was not referring to the popular children's fairy tale.

Rather, he was talking about the white coating of the Space Exploration Technologies Corp. (SpaceX) Dragon spacecraft that reflected from the International Space Station's light. As it approached the station for the first time in May 2012, the Dragon's trunk might have been described as the "fairest of them all," for its pristine coating, allowing Pettit to clearly see to maneuver the robotic arm to grab the Dragon for a successful nighttime berthing.

This protective thermal control coating, developed by Alion Science and Technology Corp., based in McLean, Va., made its bright appearance again with the March 1 launch of SpaceX's second commercial resupply mission. Named Z-93C55, the coating was applied to the cargo portion of the Dragon to protect it from the rigors of space.

"For decades, Alion has produced coatings to protect against the rigors of space," said Michael Kenny, senior chemist with Alion. "As space missions evolved, there was a growing need to dissipate electrical charges that build up on the exteriors of spacecraft, or there could be damage to the spacecraft's electronics. Alion's research led us to develop materials that would meet this goal while also providing thermal controls. The outcome of this research was Alion's proprietary Z-93C55 coating."

Kenny said Alion thoroughly tested the newly formulated coatings in the lab and provided them for NASA's Materials International Space Station Experiments (MISSE)-1 and 2 for further evaluation. MISSE-1 and 2, a test bed for materials and coatings flown on the outside of the station, evaluated the effects of atomic oxygen, direct sunlight, and extremes of heat and cold. The experiment allowed the development and testing of new materials to better withstand space environments, and the results provided an improved understanding of the durability of various materials when they are exposed to the space environment.

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