In the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, workers prepare External Tank-138, hanging vertically in the transfer aisle, for its lift onto a test cell where it will be checked out before launch. ET-138, the last newly manufactured tank, is designated to fly on space shuttle Endeavour's STS-134 mission to the International Space Station. Launch is targeted for Feb. 26, 2011. Credit: NASA/Dimitri Gerondidakis