Robotech

Robotech is an anime franchise, originally adapted from three Japanese shows from which an expanded universe was made.

Plot
Planet Earth is attacked and invaded by three different alien races - the Zentraedi, the Robotech Masters, and Invid over a period of 40 years, and has to cope with fighting back against these aliens, even when all hope is lost. But what do these three species have in common? Why were they all attracted to Earth, and who is the missing link that brings the races to Earth?

Official
robotech.com