Astronaut Jack Fischer at Air and Space Museum

NASA astronaut Jack Fischer sticks his finger in a liquid that was just boiling by vacuum, during a Stem in 30 experiment, Friday, Nov. 3, 2017 at Smithsonian's National Air and Space Museum in Washington. During Expedition 52, Fischer completed hundreds of scientific experiments and two spacewalks, and concluded his 136-day mission onboard the International Space Station, when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in September 2017. Photo Credit: (NASA/Aubrey Gemignani)