J-2X Engine Ready For Second Test Series

J-2X Engine Ready For Second Test Series: Designed To Power Upper Stage Of NASA's SLS The next-generation engine NASA says will help carry humans deeper into space than ever is back, bigger and better. The J-2X engine is currently on the A-2 Test Stand at NASA's Stennis Space Center in Mississippi for an extensive round of tests to build on last year's successful test firings.