Updated: July 12, 2010

MGM's Art directors Arthur Lonergan and A. Arnold "Buddy" Gillespie first directed their attention to the design of Robby the Robot because if was the most complex of the mechanical props required by the script, to be used extensively throughout the picture in scenes with the main actors. If Robby was not ready and working smoothly by the start of principal photography, the result would be costly production delays. The concept and design of Robby was a collaborative effort. While Cyril Hume finished the Forbidden Planet screenplay, Irving Block made little idea sketches which attempted to get away from the "tin-man look" which had dominated robot design in films up till then. "I saw the robot to look like producer Nicholas Nayfack," said Block. "He was shortish, with stubby legs, somewhat bald, and a very sweet guy."

The original screenplay describes Robby along those lines: "He has no face �" only a complicated arrangement of electronic gadgets which crackle and light-up at unexpected moments. In spite of his disproportioned arms and legs, he only very roughly suggests the human shape. His hands are tools, and various spare parts (one of these actually a metal hand) are neatly clipped to his body, back and front. He is able to rotate the upper part of his dome, and so seems to 'face' the person addressing him. A small radar antenna [comes] up out of Robby's dome, and slowly rotates."

From this description, "Buddy" Gillespie came up with the design that everyone liked, according to Arthur Lonergan, after he and Lonergan had sketched and discarded numerous ideas.

Gillespie based his design on the shape of the old-fashioned pot-bellied stove, "like the ones they used to have in grocery stores. Up to that time," Gillespie told researcher Paul Mandell, "robots in science fiction films looked like men in starched aluminum suits." Lonergan turned over Gillespie's rough design sketches to production illustrator Mentor Huebner, who refined the aesthetic look of the robot Huebner claims that Robby was his design. "I designed about fifteen of them, and they finally lit on one that was used," he said. Huebner explains Gillespie's early Robby sketch as a refinement of Huebner's concept. Lonergan, however, remembers that Gillespie originated the idea, and points out the Huebner would refine Gillespie's ideas, not the other way around.

Huebner abandoned Gillespie's slip cast rubber legs, similar in design and operation to the arms, and hit upon the jointed ball configuration for the robot's legs. "I thought of having a very short man inside, being able to look out of the stomach, and then have a false head built on him which brings him up to average height," says Huebner, . Gillespie's concept had the operator's head inside the robot's clear plastic dome.

Huebner's changes didn't alter Gillespie's basic design, but resulted in the clean lines and well-proportioned appearance that makes Robby so popular and pleasing to the eye. At the end of December 1954, Lonergan turned Huebner's work over to Bob Kinoshita, head draftsman of the art department, who would produce the working drawings and blueprints for Robby's construction under Gillespie's supervision. "One of the first things you do when you design a robot or monster," recalled Kinoshita, "is to try to confuse the audience as to where you put the guy inside. It's difficult to completely fool an audience because they know there is someone inside. But if you make an effort to confuse them it can work in your favor and make the whole creation more believable. Robby was designed so that the man inside could see out of the voice box below the glass head. The total concept for Robby came from different areas. Irving Block had some ideas, so did Lonergan, Nayfack and Gillespie. That was one of the problems with the whole show, I had something like six people to satisfy. That is why I am a firm believer in miniatures.

Nayfack wanted one to show the other executives first because Robby was a very important part of the whole film. I had to bend up all sorts of paper clips and wire, and work in all the little indicators to give the Robby miniature that computer effect. The first Robby was a little wood model, and that's what sold the idea."

Kinoshita's little Robby eventually became part of a jeep miniature built to film long shots of the robot driving Adams and his officers through the desert toward their first encounter with Morbius. With his miniature scale model of Robby approved, Kinoshita began drafting the plans from which the robot would be constructed. He completed a 11⁄2 scale plan and elevation drawing of Robby on January 6, 1955 and with the help of other draftsmen in the department spent the next eight weeks on the design and drawing of full scale plans for the construction and assembly of the robot's component parts. Kinoshita's working drawings were turned over to Jack Gaylord, head of MGM's Prop Shop, who was in charge of the molding and assembly of Robby's plastic parts. Gaylord worked out final mechanical problems encountered during construction with his own group of technicians, including Cliff Grant, Andy Thatcher, Rudy Spangler and Eddie Risher. Mechanical effects expert Glen Robinson worked closely with Gaylord and the prop shop in engineering the electrical system that would make Robby's complex head dome and chest effects panel operate.

Electricians Jack McMasters, Bob MacDonald and Max Gebinger installed the wiring and motors required. Gebinger, a glass blower, made Robby's neon voice tubes, which were rigged to a voice actuator by the sound department, to switch on and off according to the sound of Robby's dialogue spoken by the operator. Robby's electrical apparatus was powered and activated from a remote control panel, attached to the robot by a cable which could be plugged into either heel. "I was the nursemaid for Robby." Said McMasters, who activated via the controls the six rockler arms in the robot's dome which clicked as if in computation whenever Robby answered a question. For brief shots in which the cable attaching Robby to the remote control panel would be visible, the robot's electrical system could be run off internal batteries, but "they didn't last too long," McMasters remembered, "because Robby drew a lot of power." Although Robby was designed to stand about 6'11" tall with an outside diameter of 2'5", the tangle of mechanical and electrical internal workings called for a small operator. The task fist fell to prop shop technician Eddie Fisher who, at 5'6" in height and 120 pounds in weight, was just the right size. Says Fisher, who is now retired in Oregon, "The close confinement and lack of air was almost overpowering. It was hard work and one could endure it for only short intervals. One of the drawbacks of Robby was that you could not go up or down stairs or any incline. You had to be on a level surface because you could not raise the feet of the robot more than 3⁄4" from the floor. This gave Robby a distinctive, sliding-like mechanical motion in his walk. I had to carry 70 pounds of weight on my back, consisting mostly of Robby's head dome, plus the weight of the batteries on my belt. This made Robby somewhat top-heavy, and being inside amounted to a balancing act. If you bent over too far, the robot would go crashing to the floor, taking you with it!" Fisher never got to play Robby in the film, although he later operated the robot for television work. Before the start of shooting, the Screen Actors Guild stepped-in and demanded that an actor be hired to operated Robby because the robot had dialogue.

MGM capitulated and Fisher was replaced by actors Frankie Carpenter and Frankie Darro, who alternated in the role during filming. Robby exudes an aura of class, due in large part to the voice dubbed-in later by actor Marvin Miller, and the dry, witty dialogue written by Cyril Hume, expressing a friendly, benign superiority. Robby proved to be one of the film's most powerful science fiction concepts.

Story writers Allen Adler and Irving Block exhibited their knowledge of the field by including in Robby's programming the three laws of robotics as proposed by Isaac Asimov, which have as their overriding directive the command to preserve and protect human life. Thus Robby symbolizes the harmonious synthesis of scientific advance and social good, at last the powerful tool which man is unable to turn upon himself.