Celestial Sphere Assembly, Landing Window, Apollo Command Module Simulator


Display Status:

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.

Collection Item Summary:

The star fields displayed in the Apollo Command Module Simulator windows were produced by specially mounted celestial spheres. This sphere is one of the larger, 13.58 inch radius spheres, with its positioning drives, from one of two the two Command Module Simulators operated at the Kennedy Space Center during the Apollo program. Situated on the sphere are 998 stars up to and including stars of the fifth magnitude. The simulated stars are reflective ball bearings tinted to present the correct spectral characteristics and mounted on a black surface. When illuminated, the balls produce a star-like spot of light, which is projected as background into the Command Module simulator’s crew compartment windows by an array of windows and mirrors.

Ownership of major components of the Command Module Simulator was transferred to the Smithsonian in 1975.

Collection Item Long Description:


Celestial Sphere Assembly w/ Drive & Gimbal, Apollo Command Module Simulator

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum

Credit Line

Transferred from the National Aeronautics and Space Administration


steel, glass, plastic


  • 3-D (Sphere with Housing): 5 ft. × 3 ft. 5 3/4 in. × 4 ft. 3 in., 502lb. (152.4 × 106 × 129.5cm, 227.7kg)
  • 3-D (Sphere): 2 ft. 4 in. (71.2cm)
  • 3-D (Width of Sphere and two support brackets): 3 ft. 3 1/2 in. (100.3cm)
  • Other (Width of Bracket): 7 in. (17.8cm)

Country of Origin

United States of America


EQUIPMENT-Training Devices

Inventory Number