DEFINITION:

Space science encompasses all of the scientific disciplines involved in space exploration and studying phenomena occurring in outer space, such as space medicine and astrobiology. It includes:

1.Astronomy including astrophysics, stellar astronomy, planetary science, galactic astronomy, extra-galactic astronomy and physical cosmology

2.Space Exploration including manned and unmanned spaceflight

3.Astronautics including space medicine

4.Astrobiology

(Source: https://en.wikipedia.org/wiki/Outline_of_space_science)