Inside the Vehicle Assembly Building at NASA's Kennedy Space Center, external tank number 119 is being moved from the checkout cell and will be placed horizontally on the transporter in the transfer aisle. Once in the transfer aisle, technicians will reapply the thermal protection system foam that was removed in order to replace the tank's four liquid hydrogen engine cutoff sensors. The tank is being prepared to launch Space Shuttle Discovery on mission STS-121 in July. Photo credit: NASA/Cory Huston