Looking for an very old anime.
Hi, I am looking for an old anime I watched around 2000s, but I am pretty sure it is from older time.
An spaceship came back to earth and there was only one astronaut inside. The survivor went back home and he melt in pain shortly after seeing his fiancée. Turned out he got infected by some sort of virus or bacteria from the space and that's what got the other crews. His fiancée also got the virus so they have to freeze her and the protagonist went to the space to search for the origin of the virus.
The protagonist and his friend first went to a planet and found the farming robots went crazy and killed everyone and turned them into fertilizer. Protagonist's friend got killed here too and he travels alone after this. He also visit a planets with people there trying to break his spaceship so he would stuck on that planet like they are.
He eventually found where the disease originates. It is a planet with its people torturing ape-like organism by injecting these virus/bacteria in them while betting on how long the ape-like organism would last. The ending is the fiancée was cured and she married the protagonist's son.
Thank you