The mission was initially scheduled to begin on Aug. 22 but was suspended when workers noticed a mechanical error. An extendable robot began on Tuesday a two-week mission to retrieve the first sample of melted fuel debris from inside one of three damaged reactors at the Fukushima Daiichi nuclear power plant.Highly radioactive fuel and other materials in the reactors melted when a massive earthquake and tsunami in 2011 damaged the plant’s cooling systems.The plant’s operator, Tokyo Electric Power Company Holdings, has previously used small robots to examine the inside of the reactors, but this is the first time for it to collect a sample of the melted debris in what will mark the start of the most challenging part of the plant’s decadeslong decommissioning.The mission was initially scheduled to begin on Aug.