A film edited together for American television from films #5 and #6 of the 1957 Japanese serial film series Super Giant. The superhero Starman is sent by the Emerald Planet to protect Earth from belligerent aliens from the Sapphire Galaxy. The Sapphireans (or "Spherions") kidnap Dr. Yamanaka and force him to use his spaceship against the Earth.

References:
https://en.wikipedia.org/wiki/Attack_from_Space