Two sisters, 11 and 13, have built a Mars rover in a workshop in their family’s garage. The eldest explains how they got started, "When I was 11, I started taking apart calculators, clocks, and TV remote controls to see what was inside. My dad asked me if I wanted to build something myself. We started out creating simple circuits on a breadboard to light up LEDs." Their rover, which will show at New York Hall of Science, will roam around a mini-Martian landscape and analyze rocks.