An early draft of the film's story was novelized by Komatsu two years prior to its release as Sayonara Jupiter, which won the 1983 Seiun Award.

Space Linguist Millicent “Millie” Willem, a member of the Mars project, visits Chief Engineer Eiji Honda aboard the Jupiter-orbiting Minerva Base.

Millie describes her theory that aliens visited 100,000 years ago, leaving carvings on the Earth, the Moon and Mars.

Moving in for a closer look, it is revealed as a 120-kilometer long derelict spacecraft, likely the alien ship referenced in Millie’s Nazca research.

Forcibly awakened from deep sleep due to a malfunction, they discover a black hole is responsible for the comet reduction, and are killed when their craft is destroyed.

Prior to production on The War in Space, Toho offered a contract to author Sakyo Komatsu to write a science fiction film.

Toho planned a co-production US partners due to an estimated film length of three hours and the involvement of hundreds of foreign cast members.

Original director Shiro Moritani, who had previously worked on the Komatsu project Japan Sinks, died in December 1984.

[5] DVD Talk gave the film a mixed review, writing "Sayonara Jupiter will intrigue and frustrate fans of Japanese fantasy cinema in equal measure, while mainstream American audiences will find it insufferably dull and unoriginal.