> was just the technical fellow/consultant?

There is a direct lineage from the Nazi German V2 rockets to Saturn V. Wernher von Braun and his rocketry friends were involved at all levels of American rocketry and ballistic missile programs, and I am happy to say the latter wouldn't have gotten off the ground as early as they did without von Braun's guidance at all levels. At least until the end of WW2, British (and even German) aerospace was considerably further along than American equivalents. And even afterwards, the Europeans, Canadians, Brazilians and the Soviets have remained very productive in terms of civilian and military aerospace. This legacy continues today.

> the US still dominates space 10x or even 100x times. Engineering in the US is top notch

Good for the USA, but this has very little at all to do with unit systems and much more to do with just how much capital there is in the USA. And as everyone else has said, NASA uses SI. I bet these college students did, too.

Keep in mind that the metre is barely younger than the US itself, having been formalised in the 1790s.