400 



BENTHIC LABORATORY 



too great to maintain the jaw engagement in the slot. After it was apparent that the camera 

 would not lift free of the support hook, the mirror was rotated back to observe the manipulator, 

 and the manipulator was found to be retracted out of contact with the lift bracket. In view of 

 the extremely high risk of dropping the camera under this type of operation, further attempts 

 to move the camera were suspended. Approximately one hour was spent in working with the 

 camera in this attempt to reposition it. 



At 1230 the aquanaut was available once more to resume testing, and a check of the cable 

 at this time indicated that the voltage previously measured on channels 7 and 8 was not present. 

 The plug was re-engaged, a second check made of the voltage at the A to D card socket, and 

 the absence of the voltages confirmed. 



At this point the remaining task was to extract the spare card from its position in module 

 3, five slots down from the top, (Fig. 161), and insert it into the bottom slot in the same module 

 from which the faulty card had been removed. Unfortunately, the vantage point of the camera 

 for the upper slot of module 3 was poor, in that the fingers were hidden by the manipulator 

 body. Accordingly in order to extract the card it was necessary to position the manipulator 

 vertically with reference to the fifth card down in module 4 and time the traverse from corre- 

 sponding points on modules 5 and 4 until a reproducible traverse could be made by timing. The 

 traverse was then timed from the center of the card handle on module 4 to the supposed position 

 of the card handle on module 5. At this point, the manipulator was extended until contact with 

 the card handle was indicated by a slight shift in the position of the module, and the raise-lower 

 function was jogged until the jaws engaged the slot. Next, the manipulator was extended to stall- 

 out, following which it was relaxed slightly by again observing the motion of the module. With 

 the jaw-open solenoid actuated, the manipulator rotate function was jogged to center the hand 

 in the card handle. By retracting the manipulator slightly, the jaws engaged the notch and 

 locked onto the handle. The card was then extracted. During extraction, the proper alignment 

 of the manipulator was determined by observing the card deflection and jogging the manipulator 

 vertically and radially as indicated to align the card with the slot. Throughout the entire trans- 

 fer operation the jaw -open solenoid was actuated every two to three seconds to be sure that 

 the card would not accidentally be released. While transferring from the number 5 slot to the 

 bottom slot of the module, the wrist was rotated in an upward orientation so that the card 

 could not accidentally drop from the jaws. 



Considerable difficulty was experienced in replacing the card in the bottom slot. Visibility 

 conditions were quite poor, in that the lighting at the bottom of the module was inadequate for a 

 sharp TV display (Fig. 162), and the use of only one camera made it very difficult to estimate 

 distances or orientation of the card at the bottom of the module. A number of tries were re- 

 quired before the card was finally engaged in the slot. Although an accurate measurement of 

 time was not kept on this operation, insertion of the card in this slot required about 20 minutes 



Fig. 161. Benthic labora- 

 tory slot from which spare 

 diode matrix card was ex- 

 tracted 



Fig. 162. Benthic labora- 

 tory manipulator in posi- 

 tion to engage bottom card 

 of module 3 



