Replacing a wide field camera. They also swapped out three batteries and installed a mechanism for a spacecraft to capture for de-orbit at the end of the telescope's life.

Installing the Cosmic Origins Spectrograph, a device that will perform spectroscopy, the science of breaking up light into its individual components. The astronauts also conducted repairs to the Advanced Camera for Surveys, which has experienced power failures, causing two of the telescope's three observing channels to stop operating.

Replacing a sensor needed for pointing the telescope and install another blanket on Hubble's exterior.

They retrieved two experiments and install a new package of experiments on ELC-2, which is already on the station. Next they installed jumpers between segments on the left-side truss, or backbone of the station, for ammonia refills; vent nitrogen from an ammonia servicer; and installed an external wireless communication antenna on the Destiny laboratory that will provide wireless communication to the Express Logistics Carriers mounted on the station's truss.

The astronauts refilled radiators with ammonia. They also completed venting the early ammonia system, lubricated a left-side solar joint and parts of Dextre, a two-armed space station robot capable of handling delicate assembly tasks currently performed by spacewalkers.

Installing a grapple, or handle for the robotic arm on the station to grab, on the Zarya module to support robotic operations based from the Russian segment. They also installed additional cables to provide backup power to the Russian portion of the space station.