Russian investigators have traced the cause of a dramatic Oct. 11 Soyuz launch abort to a “deformed” sensor in a system that controlled the separation of a strap-on first-stage booster from the rocket’s central core stage, triggering a dramatic emergency escape for the Russian mission commander and his NASA co-pilot, senior managers said Thursday.

A cosmonaut and two NASA astronauts finished packing up their Soyuz ferry ship Wednesday and prepared to undock from the International Space Station early Thursday for a fiery descent to touchdown on the steppe of Kazakhstan to close out a 197-day mission that included four spacewalks, a full slate of research and an emergency leak repair.

A commercial supply ship owned and operated by SpaceX arrived at the International Space Station on Saturday, delivering a pair of NASA experiments to demonstrate satellite refueling techniques and monitor changes in Earth’s forests, along with a special holiday menu of turkey, candied yams, cranberry sauce and shortbread cookies.