NASA has released Schlieren imagery of supersonic wind tunnel tests of a scale model of the initial 70 tonne capable Block 1 Orion-capsule carrying configuration of the Space Launch System (SLS) which may carry astronauts to the Moon, The tests have been taking place in the Trisonic wind tunnel at the NASA Marshall Spaceflight Center. The Schlieren imaging system allows lighter and darker distortions caused by changes in refractive indexes, in turn caused by density gradients in a fluid, to be visualised. The technique is usually used to check aircraft and launch vehicle configurations at various attitudes for shock wave interactions and for air flow instabilities.
