Launch from Cape Canaveral (KSC); landing on the Edwards AFB; ISS-17A MPLM Leonardo, LMC.

Due to bad weather in Florida (25.08.2009) and technical problems (26.08.2009) the launch was delayed three times.

Following a two day solo flight Discovery docked to the ISS on 31.08.2009. Shuttle commander Frederick "C.J." Sturckow, forced by a leaky steering jet to use Discovery's big maneuvering thrusters instead of preferred fine-control vernier engines.

Joint operations with the ISS expedition 20. Transfer Stott to ISS and Kopra to the STS-128-crew. The primary payload is the Multi-Purpose Logistics Module Leonardo, containing a collection of experiments for studying the physics and chemistry of microgravity. Three spacewalks are planned during the mission, which will remove and replace a materials processing experiment outside ESAs Columbus module, and to return an empty ammonia tank assembly.

First EVA by Olivas and Stott on 01.09.2009 (6h 35m) to prepare for the replacement of an empty ammonia tank on the station's port truss, or backbone, by releasing its bolts. They also retrieved a materials processing experiment (MISSE) and a European science experiment (EuTEF) mounted outside the Columbus laboratory and stowed them in Discovery's cargo bay for their return to Earth.

In between research facilities were tranferred from Leonardo to Destiny.

Second EVA by Olivas and Fuglesang on 03.09.2009 (6h 39m) to remove the new ammonia tank from the shuttle's payload bay and replacing it with the used tank on the station. The new tank, weighing about 1,800 pounds, was the most mass ever moved around by spacewalking astronauts. After the new tank was installed, the old one was stowed in the shuttle for its return to Earth. On Earth the tank will be refueled and delivered again to the ISS during the mission of STS-131.

Third and final EVA by Olivas and Fuglesang on 05.09.2009 (7h 01m) to prepare for the arrival of the Tranquility node by attaching two 18m long cables between the starboard truss and the Unity node, the area where Tranquility will be installed. Tranquility is targeted to arrive to the station on STS-130 in February 2010. The spacewalkers also replaced a communications sensor device, installed two new GPS antennas and a new circuit breaker.

The first two landing opportunities were postponed for one day due to weather conditions. After weather didn't get better in Florida, Discovery had to land on Edwards AFB.

Stott landed on 27.11.2009 at 14:44 UTC with STS-129.