STS-114 was the first "Return to Flight" Space Shuttle mission following the Space Shuttle Columbia disaster. The Space Shuttle Discovery launched at 10:39 EDT (14:39 UTC), 26 July 2005. The launch, 907 days (approx. 29 months) after the loss of Columbia, was approved despite unresolved fuel sensor anomalies in the external tank; those anomalies had prevented the shuttle from launching on 13 July, its originally scheduled date.
The mission was completed on 9 August 2005. Due to the poor weather at Kennedy Space Centre Florida, the shuttle landed at Edwards Air Force, California, a secondary landing site.
The problem that resulted in the destruction of Columbia - debris separating from the external tank during ascent - unexpectedly recurred during the launch of Discovery. As a result, NASAdecided on 27 July 2005 to postpone future shuttle flights pending additional modifications to the flight hardware. On 4 July 2006, NASA resumed shuttle flight with STS-121.

Original Crew
Position Launching Astronaut Landing Astronaut
Commander United States Eileen Collins
Pilot United States Jim Kelly
Mission Specialist 1Japan Soichi Noguchi, JAXA
Mission Specialist 2United States Stephen Robinson
Mission Specialist 3Russia Yuri Malenchenko, RKA
Expedition 7
ISS CommanderUnited States Ken Bowersox
Expedition 6
ISS Commander
Mission Specialist 4United States Ed Lu
Expedition 7
ISS Flight EngineerRussia Nikolai Budarin, RKA
Expedition 6
ISS Flight Engineer
Mission Specialist 5Russia Aleksandr Kaleri, RKA
Expedition 7
ISS Flight EngineerUnited States Donald Pettit
Expedition 6
ISS Flight Engineer

STS-114 marked the return to flight of the Space Shuttle after the Columbia disaster and was the second Shuttle flight with a female commander (Eileen Collins, who also commanded the STS-93 mission). The STS-114 mission was initially to be flown aboard the orbiter Atlantis, but NASA replaced it with Discovery after improperly installed gear was found in Atlantis' Rudder Speed Brake system. During OMM for Discovery, an actuator on the RSB system was found to be installed incorrectly. This created a fleet wide suspect condition. The Rudder Speed Brake system was removed and refurbished on all three remaining orbiter vehicles, and since Discovery's RSB was corrected first, it became the new Return to Flight vehicle, superseding Atlantis. Seventeen years prior, Discovery had flown NASA's previous Return to Flight mission, STS-26.

The STS-114 mission delivered supplies to the International Space Station. However, the major focus of the mission was testing and evaluating new Space Shuttle flight safety techniques, which included new inspection and repair techniques. The crewmembers used the new Orbiter Boom Sensor System (OBSS) – a set of instruments on a 50-foot (15 m) extension attached to the Canadarm. The OBSS instrument package consists of visual imaging equipment and a Laser Dynamic Range Imager (LDRI) to detect problems with the shuttle's Thermal Protection System (TPS). The crew scanned the leading edges of the wings, the nose cap, and the crew compartment for damage, as well as other potential problem areas engineers wished to inspect based on video taken during lift-off.
STS-114 was classified as Logistics Flight 1. The flight carried the Raffaello Multi-Purpose Logistics Module, built by the Italian Space Agency, as well as the External Stowage Platform-2, which was mounted to the port side of the Quest Airlock. They deployed MISSE 5 to the station's exterior, and replaced one of the ISS's Control Moment Gyroscopes (CMG). The CMG was carried up on the LMC (Lightweight Multi-Purpose Experiment Support Structure Carrier) at the rear of the payload bay, together with the TPS Repair Box.
The crew conducted three spacewalks while at the station. The first demonstrated repair techniques on the Shuttle's Thermal Protection System. During the second, the spacewalkers replaced the failed gyroscope. On the third, they installed the External Stowage Platform and repaired the shuttle, the first time repairs had been carried out during a spacewalk on the exterior of a spacecraft in flight. On 1 August, it was announced that protruding gap fillers on the front underside of the shuttle would be inspected and dealt with during the third spacewalk of the mission. The spacewalk was conducted on the morning of 3 August. Robinson easily removed the two fillers with his fingers. Later on the same day, NASA officials said that they were looking closely at a thermal blanket located next to the commander's window on the port side of the orbiter. Published reports on 4 August 2005 said that wind tunnel testing had demonstrated that the orbiter was safe to re-enter with the billowed blanket.