Video: Mission control celebrates separation as anxiety builds over landing

Paolo Ferri, head of mission operations, describes the moment of relief when engineers confirmed the Philae comet lander separated from its Rosetta mothership. But anxiety is building over touchdown later Wednesday after telemetry data raised questions about the status of an important cold gas thruster designed to keep the lander from bouncing off the comet.

Follow Stephen Clark on Twitter: @StephenClark1.