Mitsubishi Heavy Industries, the prime contractor for Japan’s H-2B rocket, said Friday that engineers concluded a fire on the launch pad during a countdown earlier this month was most likely sparked by static electricity and stimulated by oxygen. The H-2B rocket launch has been rescheduled for Tuesday to start a resupply mission to the International Space Station.

Space station commander Jeff Williams and flight engineer Kate Rubins completed a smooth 6-hour 48-minute spacewalk Thursday, retracting a spare cooling radiator, installing two high-definition TV cameras and inspecting a massive solar array rotation mechanism that has experience subtle vibrations in recent months.

A Soyuz spacecraft carrying a three-man crew parachuted to the flat grasslands of Kazakhstan on Saturday, returning home from the International Space Station with cosmonaut Yuri Malenchenko, NASA astronaut Tim Kopra and British flight engineer Tim Peake.