Also, while on the subject, would an environmental science degree make you competitive for NASA's or the new and upcoming private space companies (i.e SpaceX or Virgin Galactic) astronaut selection. Many of the past and current astronauts have been graduates of test pilot school. Is NASA and the private companies also asking for more engineering and math specific STEM degrees if that is the case. Many thanks!
So I can't comment on the aviator stuff, but in a previous life I used to work as a contractor at
NASA "flying" satellites for one of the programs at Goddard Spaceflight Center and have many friends working for private space agencies (SpaceX, Boeing, etc.). My $0.02:
It's going to depend entirely upon what you want to do. If you want to build, test, and send satellites and autonomous vehicles into space, then you're going to need an engineering or hard science degree. The exception is a
VERY small percentage of specialists who assist with niche jobs like specialty payloads and developing scientific sensors and experiments. These people have PhDs with tons of post-doctoral work in their respective niche fields so it's not probable that you will get to do it with just a Bachelors.
Also, no matter what you do, you WILL need a Masters eventually. NASA and all of the space contractors put a huge amount of emphasis on advanced technical knowledge and you will need to be able to show this. You can even see this in the latest classes of astronaut selectees, who all have incredible life stories and unique technical backgrounds. If you want to work for NASA, you need to be able to stack up.
Fun Fact: The majority of the people working for NASA are not actually NASA employees but are actually contractors providing specific services to America's space program. It's all part of the aerospace-industrial complex which NASA oversees and is charged with maintaining at the highest levels of technological innovation. There are many STEM jobs working for contractors doing very cool things.
My suggestion: Decide what you want to be and then work towards it. I don't know what your motivations for studying environmental science are but make sure there's a job for you out there that you want to do with it. Also, make sure that it doesn't require a Masters or PhD. And if it does, find an employer who will pay for it.