In a spacewalk on Monday, the same astronauts plan to replace another gyroscope that failed three years ago.
On Saturday the astronauts plan to wrap up their research and prepare to return to earth.
Also on the mission, the astronauts plan to test a new camera system.
The astronauts also plan to tape "space classroom" lectures that will be used in thousands of science classes across the nation.
The astronauts also plan to replace a faulty wrist joint on the $600 million station arm.
The astronauts plan to stow the 30-foot-long satellite in the shuttle's cargo bay and bring it back to Earth.
The astronauts plan to release the observatory into an orbit 280 miles above Earth on Sunday afternoon.
As a small but important part of the mission, the astronauts plan to launch a group of tiny metal objects into space.
There are two areas that the astronauts planned to check for damage.
A Russian astronaut is planning to drive a golf ball in a coming space walk, part of a marketing agreement with a golf club company.