Astro Boy: Tetsuwan Atom - episode 7 - 17 May, 2003

Dr. Ochanomizu tells the whole secret of Atom's birth. It was the fact that Atom's birth father was actually Dr. Tenma, who had created him as a replacement for his son, Tobio, and then abandoned him. Atom is deeply hurt and troubled. At the same time, Atlas, who was defeated by Atom, is regenerated by Dr. Tenma with even more power. Atlas destroys the Tokugawa conglomerate's spaceport and heads for the Moon. Atom heads to the Moon to stop Atlas from running amok. Tokugawa also goes there to bury the monster that he has created, and all three have a face-off. In the midst of the battle, the facility is destroyed and everyone is about to be pushed out into space when a memory comes back to Atlas's mind and the situation changes. (Source: Wikipedia)