IAASA
International Armed Aeronautics and Space Administration
Preamble: It was 10 years after the launch of the first moon colony that the invaders appeared. Unfortunately they were stuck in a orbit around Jupiter so it would take 2 years journey using conventional technology to reach them for first contact. Unfortunately they decided to contact us first...
One of their shuttles raided the Earth and managed to destroy 3 city blocks in the Shanghai region. the conventional fighters used by the PLAAF were more then enough to take down these fighters but not before several thousand people lost there lives.
Several months later the IAASA was formed to combat this new threat. Their mandate was to stop and destroy all invaders in the Earth system. To this end all military or explorative actions in space would be done by the IAASA.
The best and brightest astronauts were chosen to crew the only vehicle able to intercept and destroy the Invaders before they reached the orbit of the Earth and the Moon colonies.
Fate
All living population of Earth, Moon and Mars are missing or destroyed. Grand Alliance task force was only able to find a few destroyed IAASA launch sites.