Returning to the Aquarius underwater habitat and Reef Base having spent actual time living and working in outer space, I found that its remarkable suitability as a perfect analogy to spaceflight was now clearly evident.
If you missed out on being an astronaut, why not be an aquanaut? Just as an astronaut travels in space, an aquanaut travels under water. There are a surprising number of careers underwater. Scuba diving is one way to be an aquanaut.