The shuttle landed back on Earth at 2.53am.
A brake parachute was deployed as the shuttle touched down.
The seven astronaut crew remained onboard while NASA staff inspected the Discovery to ensure that it was not damaged before they could descend in safety.
After their return the crew will undergo medical examination.
Christer Fuglesang and his fellow crew members will then spend the night at the Edwards base before being flown to Houston in the morning.
The Discovery mission was the fourth of five planned for the shuttle program this year with the last is scheduled for November.
Just six more shuttle flights now remain before NASA’s three shuttles are retired in September 2010.