The second robot Tokyo Electric Power Company (TEPCO) sent into Fukushima's unit 2 reactor also failed to finish its mission. Earlier this month, the cameras of the first "scorpion" robot that ventured into the reactor malfunctioned after two hours due to extremely high radiation levels. Now, it's the machine's left crawler belt that stopped working (PDF) altogether, forcing TEPCO to cut off its tether and to leave it inside.