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Quick History of Aerospace Affects on MOL Payload 

1. An early decision was required to resolve the pointing control 

configuration of such a large aperature optical system and, so Aerospace 

lead a study to select the In line Configuration where a tracking mirror 

is utilized rather than the direct pointing of the entire optical barrel 

(called "Dump Truck"). 

2. Aerospace selected a tracking mirror drive configuration utilizing 

direct drive d. c. torquers and ball bearings and recommended GE for the 

task (of the Associates in the program). 

3. Aerospace orbital dynamics studies le to removal of the tracking 

mirror from attachment on the optics barrel and recommended a Beryllium 

tripod gimbal supported from the Laboratory Module structure. 

4. Further orbital dynamic analyses have required that Aerospace 

derive the complex optical element's vibration sensitivity matrix and 

obtain all associate contractor's approval to utilize this matrix on all 

future studies to determine the significant:stiffness requirements and 

major sources of perturbation on the orbiting vehicle. 

5. Derived the original system performance error analyses which 

Lilt to definitions showing: 

a. Need for IVS in automatic version 

b. Need for Star Tracker in automatic version 

c. No need for GE proposed extra platforms and gyros 

d. No need for GE proposed gyros on COA 

e. Need for Alignment monitor set 

f. Need for digital computer 
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g. Establish need for backup with Low G 

h. Establish need for other methods of better ephemeris - 

6. Derived and published original ground target rate tracking 

equations to produce nominal ground target tracking rate outputs from 

airborne digital computer. 

7. Derived pointing equations. 

8. Aerospace derived the soft, slew logic required to prevent 

undue perturbations of the tracking dynamics. 

9. Aerospace designed the required navigation equations and 

software methods to be utilized; 

10. Field Break was Aerospace recommendation saving a great 

deal irf ground facilities, especially at Philadelphia. 

11. No single failure concept and redundancy was Aerospace 

recommended. 

12. Single most important development tool was recommended by 

Aerospace, namely the Brassboard of Tracking Mirror Drive, which 

has uncovered many problems requiring early attention. 

13. Aerospace wrote the black mission portions of the SP/DR. 

14. Aerospace wrote the GE-AVE CEI Specification. 

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1. A decision was made in January 1967 to convert the 

thermal door design from one actuated in roll to a linear 

sliding mask moving in the longitudinal direction. The rolling 

design was a GE design and would not provide adequate 

thermal protection of the tracking mirror. View factor data 

was obtained on the rolling design and was used with an 

Aerospace computer program providing temperature 

error 

distribution and resultant distortion to determine that 

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excessive distortion resulted from the rolling design. A 

decision was then made to use the sliding mask design with 

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2. GE is using a ball bearing design for the tracking 

mi rror drive system. Concern whether the bearings would 

create excessive noise in the tracking mirror drive loop was 

expressed to GE in January 1967. Suggestions were made to 

expand tave bearing test program, particularly to obtain power 

spectral density data on bearing noise. The resulting 

expand test program is leading to a better understanding 

of the factors that lead to degraded tracking mirror drive 

performance. In addition, suggestions were made to GE on 

the installation and bearing preload design which lead to an 

improved design for tracking mirror drive performance. 

3. A study was made of the capability of the flight alignment 

monitor system to be used for ground alignment of the camera 

optical assembly with respect to the tracking mirror drive 

reference. It was determined4 that a seismic-mass, was not 

required at Huntington Beach for alignments. 

4. A decision was made to provide a high resolution 

acquisition and tracking system for active target assessment 

by the crew. A decision to use an all optical system rather 

than TV was made. 

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