A long time ago, when I was at NASA, I remember the closure of the Shuttle program. In its subsequent place and alongside the relative success of commercial crew, came the Space Launch System (SLS). Working in aeronautics and research, I assumed I would remain involved in fundamental research. That did not last, and by choice I became briefly involved. A friend called me over to the Unitary Wind Tunnel at NASA Langley, and I found myself holding one of the earliest aerodynamic models of SLS in my hands. It was small, metal, stored in a wooden box, and mounted at various angles and Mach numbers in the wind tunnel. Instrumentation was mostly for unsteady aerodynamic loading during critical ascent phases.
I became involved at first by helping oversee a committee examining aerodynamic data from the wind tunnel, focused on unsteady aerodynamic loading during ascent. This involved studying coupled aero, vibro-acoustic, and structural response of the SLS. Review committees looked for two-point cross-correlations of unsteady pressure. These could be predicted by a more mathematical theory I previously developed or processed into narrowband cross-spectra. However, they approach only looked for coherence length and a single aimplitude at single-point (not two-point) locations. In the end, the tried and true way of the past gave more conservative estimates for structures and damping components than more recently advanced methods would yield. The whole thing was a bit disappointing and I could see how much beaucracy there was on the space side of NASA.
This memory came back to me while watching the Artemis II / SLS launch with family yesterday. A small metal model, perhaps eighteen inches long, once held in my hands inside a wind tunnel, now ascending at full scale and observed by millions of people.