Members of a NASA-led tour group look up at the

Members of a NASA-led tour group look up at the 215-foot-tall Structural Test Stand 4693, Feb. 6, 2019, which now houses the Space Launch System's liquid-hydrogen fuel tank structural test article, at Marshall Space Flight Center's West Test Area at Redstone Arsenal, Alabama. NASA engineers are gearing up to use the test stand, which the U.S. Army Corps of Engineers' Mobile District completed in November, to put the fuel tank through a battery of structural qualification tests well before the unmanned Exploration Mission 1, scheduled for 2020, which is designed to the be first step in future human exploration of the Moon and Mars.