The advantages of joining a space exploration program as a scientist or an astronaut include the satisfaction of solving an intellectual challenge, the high salary and the adventurous experience. Some of the cons are that the results of one's work are not immediately seen, as space exploration is a long term goal, as well as the expensive and long training process required to join a space exploration program.
There are different ways in which one can join a space exploration program, mainly as an Earth-based scientist or as an astronaut. Earth-based scientists first design the technology needed to explore the space and then send a manned or unmanned vehicle to space. If the vehicle is manned, it is possible to join the program as an astronaut. Each job has its own pros and cons.
Joining a space exploration program as a scientist or engineer has many advantages. First, space exploration poses an intellectual challenge, since space is widely unknown. Second, science and engineering jobs are well-paid. On the other hand, space exploration is a long-term goal, and the process is very slow, so the results of one's research are not immediately visible.
Astronauts are also scientists and engineers, but in addition they need to be trained pilots and must pass a physical exam. The pros for joining a space exploration program as an astronaut are the same as those of joining as an Earth-based scientist, in addition to the satisfaction of the desire for adventure. On the other hand, the training for becoming an astronaut is very expensive, long and difficult, and the odds of actually going to space are very low. Furthermore, some space missions can be dangerous, since any accident can be fatal.