Wait, is that... human bones on Mars? Not quite, conspiracy theorists: in fact it's just a rock that happens to look a little bit like a femur thigh bone. It was snapped by the Mars rover Curiosity using its MastCam. [NASA]
This astronaut Alexander Gerst as he guides in the Automated Transfer Vehicle 5 to dock with the ISS. In his hand? A simple plastic ruler. Someone aboard the ISS must manually check the approach speed of the cargo vessel to ensure its safe docking. That check involves holding a clear plastic ruler to a display to check the speed.