NASA astronauts Sunita Williams, Don Pettit, Nick Hague, and Butch Wilmore shared a holiday greeting and expressed well wishes to those back home on Earth. Williams and Wilmore have been stranded in space since June.m In another development, The North American Aerospace Defense Command continues its decades-long programme in which it simulates the tracking of Santa Claus as he leaves the North Pole to travel around the world with a mission to deliver gifts to children on Christmas Eve. Watch NDTV'S The World Report for the latest updates.