change involved a new low-density foam application, and thinner gaskets. Shuttle Program Managers decided to do this to reduce the foam loss from the area that had been noted since STS-114's "Return to Flight" mission in 2005. STS-118 had a small gouge on the belly of the orbiter due to a chunk of foam that impacted during launch in August 2007. The week of September 17, 2007, NASA managers decided to delay Discovery's rollover to the Vehicle Assembly Building (VAB), due to a hydraulic fluid leak from the right main landing gear strut. The strut repair was successfully completed on September 19, 2007. Discovery then moved to the VAB, and was mated to the External Tank and Solid Rocket Boosters. Perched atop the mobile launcher platform, Discovery arrived at Launch complex 39A on September 30, 2007. The crew of STS-120 arrived at Kennedy Space Center on October 7, 2007, and began final preparations, including the terminal countdown demonstration test, or "Dress Rehearsal", scheduled for October 7, 2007, through October 10, 2007. On October 9, 2007, NASA's Engineering and Safety Center, an independent review group set up after the 2003 Columbia disaster, advised replacement of three of Discovery's reinforced carbon-carbon (RCC) panels on the leading wing edge, due to a loss of small amounts of the protective silicon-carbide coating. NASA reviewed the issue of oxidation of the panels for several months, using a variety of specialized testing methods, including thermography. These tests showed that the panels had not worsened over the course of the past two flights of Discovery, and the orbiter project engineers concluded in August that Discovery was safe to launch as is. Had a decision been made to repair the panels, the orbiter would have been rolled back to the VAB, delaying the launch. On October 16, 2007, NASA Managers completed the Flight Readiness Review, and held a press conference to announce the mission plan. The issue of the RCC panels raised by NESC was found to be of little immediate concern, because the NESC took pre-flight thermography data from Endeavour and compared it with Discovery, but there was no commonality in flight history between the two vehicles. The research showed no significant difference between the panels prior to STS-114, and the panels today, which indicates the coating has not worsened during the previous flights, adding confidence that Discovery's RCC panels have had no deterioration in the flights