The series has now been added to the Crunchyroll library where the full twenty-six episode run is now available in either it’s dubbed or subtitled forms here.
Plot concept: Thirteen years after their sudden disappearance, an alien race known as the Heterodyne resurface without warning.
Originally known as Chikyuu Bouei Kigyou Dai-Guard when it aired back in 1999 for two cour, the twenty-six episode series saw release a few years later on DVD in North America.