Among the most intriguing and accurate fictional spacecraft is the SPACE:1999 Eagle shown on the above right cover illustration. For example, one feature which most science fiction artists overlook was a realistic reaction control system for the Eagle's orientation control in pitch, roll, and yaw. Additionally, the Eagle's structure, a "strongback" grid, made the ship an appropriate cargo carrier of a cargo pod. As an interplanetary craft like Neil Armstrong's LEM, the Eagle's design included landing footpads and retro-engines for descent and ascent. Four space shuttle type main engines provided translation propulsion between planetary bodies. A command module-like crew compartment served as the Eagle's command and control station. The command pod had more than adequate viewing windows for the astronaut pilots to maneuver the vehicle properly.
Only a few unrealistic features were included in the Space 1999 Eagle based on current space technology. One was the sizing of the propellant tanks with regard to the extent of the four main engine nozzles. The space shuttle SSMEs (SPACE SHUTTLE MAIN ENGINES) are approximately the same size. The three SSMEs require an enormous eternal tank. Of course, the space shuttle engines must launch the shuttle from the six times greater gravity of Earth while the Eagle lifts off from the Moon's surface.
Written in 1976, SPACE:1999's fulfillment is past with the arrival of the new millennium. Had space technology developed new fuels with magnitudes greater energy levels (ISPs) than the cryogenic fuels of the Apollo era, Eagle's main engines would be appropriately sized with respect to her propellant tanks.