NEEMO Undersea Crew Tests Tools and Techniques For Future Spacewalks

This photograph of NASA astronaut Serena Aunon (@AstroSerena) moving tools and equipment underwater was taken during the NASA Extreme Environment Mission Operations (NEEMO) 20 mission. NEEMO 20 is focusing on evaluating tools and techniques being tested for future spacewalks on a variety of surfaces and gravity levels. via NASA

Frosty Gullies on the Northern Plains of Mars

Seasonal frost commonly forms at middle and high latitudes on Mars, much like winter snow on Earth. However, on Mars most frost is carbon dioxide (dry ice) rather than water ice. This frost appears to cause surface activity, including flows in gullies. via NASA

Round of Testing Completed on Webb Telescope Flight Mirrors

This July 11, 2015 photograph captures one of the final, if not the final, James Webb Space Telescope flight primary mirror segments to be processed through NASA Goddard Space Flight Center’s Calibration, Integration and Alignment Facility (CIAF). via NASA

Activity at Klyuchevskoy Volcano

This photograph, taken on May 4, 2015 by an astronaut onboard the International Space Station, highlights one of the most active volcanic regions on Earth: the Kamchatka Peninsula in far eastern Russia. The three largest volcanoes visible at image center include Kliuchevskoy, Bezymianny, and Ushkovsky. via NASA