Saw this when I was 11 years old, I recall the rocket fighters sent up by the Earth Forces are based on the X-15 rocket plane. One thing I remember-and it moved me at the time, and is one of the movie's strengths-is the scene where the earth space ships go past the area where the space station was destroyed-and you see the bodies of the crew. The action moves at a brisk pace, no long winded speeches or philosophizing. The SFX are pretty good for the time. As a side issue, I got a chuckle when I saw "Star Wars" in 1977, I recognized the "futuristic weapons" as being models of British Lee Enfields, German MG-42 machine guns, Heckler & Koch submachine guns.