Discovery astronaut becomes 200th to go on spacewalk
An American astronaut has become the 200th person to walk in space during Discovery's final mission to the International Space Station.
Alvin Drew joined spacewalk veteran Stephen Bowen to install an extension cable and move a broken ammonia pump to a new storage location.
The pair will also open a small metal canister, destined for display in Japan, to expose its interior to outer space.
28 Feb 2011