Two J-2X engines and a powerpack, developed for NASA by Pratt and Whitney Rocketdyne, sit side-by-side Oct. 11 at Stennis Space Center as work continues on the Space Launch System. Engine 10001 (far left) has been removed from the A-2 Test Stand after being hot-fire tested 21 times, for a total of 2,697 seconds. The engine is now undergoing a series of post-test inspections. A J-2X powerpack (center) has been removed from the A-1 Test Stand to receive additional instrumentation. So far, the powerpack been hot-fire tested 10 times, for a total of 4,162 seconds. Meanwhile, assembly on the second J-2X engine, known as Engine 10002 and located to the far right, has begun in earnest, with engine completion scheduled for this November. Engine 10002 is about 15 percent complete.