In the scene where the reporter and one of the professors go back to check for damage. The round red object he opens up is a complete (minus 2 machine guns) belly ball turret for a B-17 bomber from World War II. It is minus it's revolving and raising and lowering mechanisms.
The name of Marguerite Chapman's character is derived from the Queen of Mars from the classic Soviet silent film Aelita, the Queen of Mars (1924).