I'm an ex-ex-rocket scientist. I briefly left the NASA fold to work at a startup filled mostly with similar ex-rocket scientists. We applied what we learned about making rockets reliably, economically, and safely move from point A to point B to all kinds of other devices that move from point A to point B. I came back to the NASA fold because, in hindsight, that was not the best time to make the jump to oil and gas (upstream).