On disk 2 select the 'Data Console' option. Then highlight the 'Main Menu' entry and then press right on your remote. A red LED will light up on the computer, so press enter. The alien ship will start hover in the background, and the computer will display the message 'Access: 7-4-Enter'. Now select 'Main Menu' to go back to the main menu. Once there press 7, 4 and enter on your remote. You will then enter the ship.
All easter eggs were generously submitted by spikey2000