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Spacecraft Position Display Indicator

IP.com Disclosure Number: IPCOM000093597D
Original Publication Date: 1967-Nov-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 4 page(s) / 77K

Publishing Venue

IBM

Related People

Woods, DR: AUTHOR

Abstract

Indicator 10 simulates a global display of a rotating celestial body as seen from an orbiting satellite or spacecraft. At the front or viewing end, drawing A, ground track arrow 11 is inscribed on transparent window 12 of drawing B. Also inscribed on window 12 is one or more concentric circles, e.g., circular lines 12a and 12b. The latter encompass the horizon fields of view for one or more orbital altitudes. Preferably, circles 12a and 12b encompass the respective fields of view for the maximum and minimum altitudes associated with the apogee and perigee of a particular spacecraft orbit.

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Spacecraft Position Display Indicator

Indicator 10 simulates a global display of a rotating celestial body as seen from an orbiting satellite or spacecraft. At the front or viewing end, drawing A, ground track arrow 11 is inscribed on transparent window 12 of drawing B. Also inscribed on window 12 is one or more concentric circles, e.g., circular lines 12a and 12b. The latter encompass the horizon fields of view for one or more orbital altitudes. Preferably, circles 12a and 12b encompass the respective fields of view for the maximum and minimum altitudes associated with the apogee and perigee of a particular spacecraft orbit.

Inner hollow globe 13 carries a topographical facsimile of the celestial body, e.g., the earth, on its outer surface. This surface is also scored with suitable location indicia, e.g., lines 14 and 15, which in the example correspond to predetermined latitudes and longitudes of the earth. Sphere 13 is supported for rotation about shaft 16, the ends of which are fixed to cylindrical projections 17 and 18 of an intermediate, transparent, plastic and hollow sphere 19.

Shaft 16 is connected to planetary gear system 20. The latter is driven by variable speed miniature servomotor 21. Elements 20 end 21 are part of the globe rate drive system for rotating globe 13 about global axis GA.

Motor 21 is mounted on supporting platform 22 which is formed as part of or affixed to the inner surface of globe 13. Sphere 19 has a pair of diametrically opposed flat-like projections 23 and 24. The latter project through the slits 25 and 26 of the outer, transparent, plastic and hollow sphere 27. Upper projection 23 supports gear rack 28. This coacts with gear 29 and screw 30 for adjustment of the angle of inclination of sphere 19, and consequently globe 13, with respect to arrow 11. For this purpose, insulator knob 31 is provided end connected to the shaft of screw 30, which is freely rotatably mounted within the necked-down portion of hollow projection 32.

Sphere 27 has a pair of diametrically opposed axial projections 32 and 33 which are rotatably supported by the ball and pivot bearings 34 and 35, respectively. Sphere 27 is rotated by worm gear assembly 36. The letter is connected to solid praxial projection 33 end driven by another miniature servomotor, not shown, mounted within the housing of indicator 10. This servomotor, when actuated, rotates spheres 27 and 19 about the orbit axis OA and together with assembly 36 is part of the orbit rate drive system. As a result, in addition to its rotational motion about axis GA, globe 13 is rotated about axis OA by the orbit rate drive system. For easy assembly of the constituent components contained in them, each sphere 13, 19, and 27 is configured as a pair of mating hemispheres which are made of an electrical insulating material.

A commutation system is provided for energizing motor 21. It includes slip rings 37...40, partially shown in cross-section, and brushes 41...44, shown schem...