NPR Science & Technology Rosetta On Course To Achieve Historic Mission By Rob Stein Published January 21, 2014 at 12:00 AM EST Facebook Twitter LinkedIn Email Listen • 2:35 Rosetta On Course To Achieve Historic Mission Listen • 2:35 Copyright 2014 NPR Corrected: January 21, 2014 at 12:00 AM EST In this story, we say the Rosetta spacecraft weighs 6,400 tons. We should have said 6,400 pounds.