TFO

The TFO (Terrestrial Flying Object) is a space ship Koji Kabuto created after researching through NASA's files on UFOs. It was originally built for transport and for communicating with aliens, able to move into the ionosphere. However, when the Vegan Empire attacked and Koji was almost shot down in episode 1, a missile system was added to provide weaponry. The missiles were only effective against the weaker enemy forces and the TFO was eventually destroyed in episode 27,  replaced by JFO and then the Double Spazer.

Trivia

 * The TFO served a similar role to the female robots of the Mazinger anime, with its only weaponry being a missile system and was usually the one suffering the most damage until it was destroyed.
 * While the TFO is heavily associated with its presence in Grendizer, the TFO had actually debuted in Go Nagai's Great Mazinger manga, where Koji used it to assist Great Mazinger in killing General Birdler.