Sojourner, the small exploration vehicle that landed on Mars in July 1997, was controlled by the ground station of the American space authority NASA. Commands were sent to the Sojourner from there. It was asked to travel over the surface of Mars, take photographs, soil samples, and lots more. There were glitches too. On the first day, Sojourner collided with a rock because it was travelling too fast. And sometimes the computer onboard ‘rebooted’ so the robot ‘forgot’ what it was supposed to do.