Shuttle launch: Dramatic last-minute delay to lift-off
Just seconds before the final Nasa shuttle launch, Mission Control halted the countdown over concerns about a piece of launchpad equipment.
There were worries that the gaseous vent arm had not been completely moved out of the shuttle's way.
British-born former astronaut Piers Sellers explained to the BBC's Pallab Ghosh what would happen if the launch had to be scrubbed at such a late stage.
But after controllers were satisfied there were no problems, the signal was given to proceed with lift-off.
08 Jul 2011
- From the section Science & Environment