GURPS Spaceships covers spaceship design, travel, and operations, along with a (mapless) space-combat system.
The ship design and operation rules in GURPS Spaceships are more abstract than those found in GURPS Vehicles or GURPS Traveller: Interstellar Wars . . . making them much faster, with a minimum of math and a maximum of colorful options. It takes only minutes to build even the largest spaceship . . . and wrapped around the design system are basic space-travel and combat systems to get players into space right away!