Nasa's Dart asteroid crash 'exceeded expectations'
The American space agency's Dart probe has smashed into an asteroid, destroying itself in the process. The collision was intentional and designed to test whether space rocks that might threaten Earth could be nudged safely out of the way. Dr Nancy Chabot has been the mission's co-ordination lead at the Johns Hopkins University Applied Physics Laboratory. She describes the success of the impact and the feelings she had when watching the probe's last moments.
