Many have asked how this photo was made. This is my explanation. The ISS rotates about its pitch axis as it orbits Earth at 17,000mph to keep its nadir view constant. Because of this long exposure photography turns stars into arced lines. Sidereal clock drives on Earth match the planet's rotation to see stars clearly. I knew one designed for space could do this too. So a camera mount was custom built at @RITtigers to rotate once every 90 minutes using a 60 to 90 toothed gear system, cancelling out the orbital motion of ISS and allowing the capture of distant stars as fixed points! In essence, it is a a rotational coil spring powered analog star tracker. It was machined out of aluminum and is entirely mechanical to bypass NASA's strict electrical requirements for cargo. We had to get creative! After Expedition 72 it was safely returned to Earth and is to be displayed at RIT. Which I am pleased to say because a similar barn door tracker I made from spare parts on Expedition 6 for nighttime city photography was destroyed in an atmospheric trash disposal! Photography is an important part of sharing the journey to new frontiers for all people of Earth!