Not everyone can be out in space but…
With the renewed interest that our astronauts have created with the final frontier it is to be expected that a whole generation has been inspired to want to head out into space. Unfortunately not everyone can be out in space but for every one astronaut there are at least a hundred people involved with the mission on Earth itself.
To be a part of the supporting staff is just as exciting and challenging as it is to be an astronaut. Not to mention much safer as a career option since you never face the uncertainty and risks of space travel first hand. You still get to be in on the plan to explore the moon, another planet or even other galaxies.
As an astronomer you can help to determine the composition of a planet, its atmosphere, and its moons. You can help figure out if it is likely to support life. You can even have plans of relocating human beings to a hospitable planet and you can get to explain it all to a public audience.
You can be part of the force that protects Earth from collisions with other potential treats. By using sensitive radio telescopes to spot comets and asteroids with the potential to impact Earth, you can give early warning orders that can help deal with the threat. There is more than one interesting science project that you can be part of.