Phil Hendrix, right, and Curtney Walters compare blueprint plans of Structural Test Stand 4697 to the nearly completed structure at NASA's Marshall Space Flight Center in Huntsville, Ala. While construction of the stand is complete, over the next few months Marshall engineers will install special test equipment to prepare Test Stand 4697 for its first mission: subjecting the 196,000-gallon liquid oxygen tank in the massive core stage of NASA's Space Launch System to the same stresses and pressures it will endure at launch and in flight. Hendrix is the Marshall Office of Center Operations facilities construction project manager for the stand, and Walters is project engineer with the U.S. Army Corps of Engineers, Mobile District, the contracting partner on the project.