Leonardo began receiving modifications and reconfigurations immediately to convert it for permanent attachment to the space station and to facilitate on-orbit maintenance.

Additional modifications to Leonardo included the installation of upgraded multi-layer insulation (MLI) and Micro Meteoroid Orbital Debris (MMOD) shielding to increase the ability of the PMM to handle potential impacts of micrometeoroids or orbital debris; a Planar Reflector was installed at the request of the Japanese Space Agency (JAXA).

Once JAXA's Kounotori 2 (HTV-2) arrived in February 2011, Leonardo's now-unnecessary launch hardware was transferred to HTV2 for ultimate destruction in Earth's atmosphere.

Its inclusion on STS-133 was part of a final test run ahead of being fully implemented on SpaceX's Dragon spacecraft, which had its maiden flight in December 2010.

It provides both range and bearing information from targets that can reflect the light back such as the pressurized mating adapter 2 (PMA2) and those on the station's Japanese Kibo laboratory.

The original crew consisted of commander Steven Lindsey, pilot Eric Boe, and mission specialists Alvin Drew, Timothy Kopra, Michael Barratt, and Nicole Stott.

Commander Steve Lindsey and Pilot Eric Boe also performed abort landings and other flight aspects in the Shuttle Training Aircraft (STA).

[24] Flying aboard NASA T-38 training jets, the six astronauts returned to Kennedy Space Center on October 28, 2010, for final pre-launch preparations.

[25] On January 15, 2011, Timothy Kopra, scheduled as the lead spacewalker for the mission at the time, was injured in a bicycle accident near his Houston-area home, reportedly breaking his hip.

Discovery was moved from its hangar in the Orbiter Processing Facility (OPF)-3 to the nearby 52-story Vehicle Assembly Building (VAB) on September 9, 2010.

The move did not commence due to the unavailability of fire suppression systems because of a broken water main near the VAB and turn basin that runs out to the shuttle launch pads.

The leak was detected after they noticed a fishy smell coming from the aft of the shuttle, thought of as a sign of fuel vapor in the air.

[34] Subsequent leak tests showed again signs of seepage, and the task of solving the issue required the draining of both the left and right OMS tanks of the shuttle and a unique in-situ repair at the pad to avoid a rollback.

[37] Normal pad operations commenced soon after allowing managers to press forward with the confirmation of a November 1, 2010, target launch date, with fuel reloading into the OMS tanks beginning on the morning of October 24, 2010.

On November 5, 2010, Discovery's launch attempt, a hydrogen leak was detected at the Ground Umbilical Carrier Plate (GUCP) during the fueling process.

Teams performed an initial inspection of the flight seal and a quick disconnect prior to sending them to labs for thorough engineering analysis.

Engineers reported an unevenly (asymmetrically) compressed internal seal and the quick disconnect hardware also seemed to have a less concentric fit than pre-fueling measurements indicated.

The new plate was previously fit checked on the external tank at the Michoud Assembly Facility and yielded substantially better concentricity values than was obtained with the old and removed GUCP.

In December 2010, with the Shuttle still on the launch pad, a full tanking test was performed to understand that failure modes of the SOFI foam fracturing.

[47] "What we've told the agency leadership is that clearly we're not ready for the 3 to 7 December window that's coming up next week," John Shannon, NASA's SSP manager, said in a news conference held after the special PCRB.

[64] Once on orbit, the crew of STS-133 opened the payload bay doors and activated the Ku band antenna for high-speed communications with Mission Control.

The day started with a firing of the Orbital Maneuvering System (OMS) engine, called the NC2 burn, to help Discovery catch up to the ISS.

Commander Steve Lindsey, Pilot Eric Boe and Mission Specialist Al Drew began the day performing an inspection of the Re-enforced Carbon-Carbon (RCC) panels with the Orbital Boom Sensor System (OBSS).

Drew joined up with Michael Barratt and Steve Bowen to checkout and get their two Extravehicular Mobility Units (EMUs) ready for the two spacewalks that would be conducted during the mission.

On Flight Day 4, Stott and Barratt grappled the Orbiter Boom Sensor System (OBSS) using the Canadarm2 and removed it from the starboard sill of Discovery's payload bay.

The OBSS was grappled by the space station arm, because the SRMS could not reach it due to clearance issues, and it needed to be moved out of the way so that the Permanent Multipurpose Module (PMM) could be removed from the payload bay.

After the OBSS handoff, the entire STS-133 crew was joined by ISS Expedition 26 commander Scott Kelly and flight engineer Paolo Nespoli for a series of in-flight media interviews.

The interviews were conducted with the Weather Channel, WBZ radio in Boston, Massachusetts, WSB-TV in Atlanta, Georgia, and WBTV in Charlotte, North Carolina.

Later in the day, they were joined by the shuttle crew and ISS commander Kelly and Flight Engineer Nespoli, for a review of the spacewalk procedures.

After the review, Bowen and Drew donned oxygen masks and entered the crew lock of the Quest airlock for the standard pre-spacewalk campout.