Skylab 3-Dimension Orbit Model. A 10-in. diameter globe of the earth standing approx. 19 in. tall mounted on a 10 diameter metal base with a large gold arrow pointing toward "Sunlight". The model was designed by the Houston Manned Spacecraft Center for internal use. It provided a three dimensional visualization of the orbital ground track of the Skylab space station via means of a 21-in. rotating plexiglas disk. Inserted in this disk is a 5 in. metal model of the Skylab space station with the words "Solar Inertial Mode" and "Point to Sun" engraved on a metal support ring. The large rotating disk can move from zero degrees to over 60 degrees in orbit inclination via a green anodized mounting arm located at the north pole. Two anodized rings (red and blue) at the pole provide measurement of the orbit angle of regression.