Holding a job change people's character when they are doing the job they like. if there are job satisfaction, then a lot profit can be gain such as respect,confidentiality and desire to work. They surely spend less of their hard earn money.
As for the first part, Cost, Radiation exposure to humans, No water or heat, and unfit soil. As for the second, Astronomers, Botanists, and obviously your fair share of rocket scientists and math matitions for the way up.
The alien was able to defy the laws of gravity.
Hope this helped! (:
