6894 Invader is a Blacktron set released in 1987. It contains the Invader, a small robot and a Blacktron Astronaut minifigure. The set costed $14.25 USD and had 156 pieces.
The ship included three main sections: The cockpit section, the cargo container in the middle and the drive section at the aft. The sections are compatible with other Blacktron sets. The ship had tiles on it that included the Blacktron symbol.