I've been considering a change in career direction recently, and have been thinking about a career in developing scientific instrumentation. I know that "scientific instrumentation" is vague and encompasses a lot, hence the reason I am posting -- to try sharpen my understanding of exactly what types of careers are out there. As a starting point: there exist teams responsible for building the Hubble space telescope, LISA, the LHC, etc. This is the type of "instrumentation" I am talking about -- large scale scientific experiments. Obviously, a huge number of people are involved in such projects. Can someone provide me with a broad categorization of the type of roles people play in such projects along with the type of preparation best suited for such roles (physics, EE, masters, phd, etc.) and where/for whom such people work (private companies, universities, etc.)?