By Liz White, UT staffThe redesigned polyurethane-coated fuel tank that will help launch the Space Shuttle Discovery on its 'Return to Flight' mission started its journey to Florida on 30 Dec 2004 from its production site at NASA's Michoud Assembly Facility near New Orleans. The massive external tank, known as ET-120, was loaded onto a covered barge for a five-day journey to NASA's Kennedy Space Center in Florida.Chunks of insulating foam falling off the external fuel tank are now believed to have led to the disastrous accident which happened to the last Space Shuttle, Columbia, in January 2003. Investigators believe that during Columbia's launch, insulating foam from the bipod area fell off the tank and damaged the left wing of the Orbiter. This train of events led to Columbia's break up during re-entry, killing the seven astronauts on board. ET-120 incorporates various safety improvements. These address recommendations by the Columbia Accident Investigation Board's, designed to reduce the possibility of damage to the shuttle from falling debris during ascent. The orange external tank (see picture) is the largest element of the Space Shuttle system at 27.6-ft wide and 154-ft tall (8.4 x 47 metres). During the first eight-and-a-half minutes of launch, the tank feeds 535 000 gallons of liquid hydrogen and oxygen to the shuttle's three main engines, powering the shuttle into space during ascent. The tank is the only shuttle component not reused. The tank project is managed by the Space Shuttle Propulsion Office at NASA's Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space Systems Co. is the primary contractor for the tank.Some idea of the massive scale of the tank can be seen from the picture, showing the tank being moved towards the barge."