Encyclopedia Astronautica
1967.12.20 - Coax cable problems in Apollo CSM 103


As a part of the managers' technical status review, Dale Myers of North American Rockwell presented his analysis of fixes for the coax cable in spacecraft 103 and subsequent spacecraft.

The North American recommendation was:

- For spacecraft 103, 104, and 106 - remove all coax and wrap with aluminum tape using a 75- to 90-percent overlap. Re-install wrapped coax with additional teflon overwrap in areas where chafing might occur. This wrapping would increase spacecraft weight by 0.9 kilograms. Schedule impact was estimated at five days for spacecraft 103 and 104 and one day for spacecraft 106.

- For spacecraft 107 and subsequent spacecraft - install new coax cable that would meet nonmetallic-materials guidelines. There would be no schedule impact.

According to MSC's CSM Manager Kenneth S. Kleinknecht, the North American recommendation was justified for the following reasons:

- All coax would be installed before the inspection process.

- Spacecraft 106 was ready for electrical harness closeout; fabrication of new cables, with guideline material, would delay closeout by about three weeks.

- The new cable to be used in spacecraft 107 was already used on the spacecraft upper deck, but had not been subjected to corrosive contaminants, oxygen, and humidity qualification. This qualification would be completed in line and before cable installation.

- Although connectors used with coax on the upper deck were compatible with black boxes in the spacecraft and were supposedly available, there were not enough in stock to support the fabrication of new cables for spacecraft 103, 104, and 106.

- Testing at North American and MSC supported the conclusion that wrapping with aluminum tape would preclude propagation of burning if ignition of the coax should occur.

Kleinknecht decided, with concurrence of Maxime A. Faget and Jerry W. Craig, to accept the proposal and Myers was authorized to proceed, subject to concurrence by Program Director Samuel C. Phillips and Program Manager George M. Low. Kleinknecht received oral concurrence from Low and Phillips on December 20; then, in confirming the decision with Myers, he requested that North American develop a schedule recovery plan to negate the impact of the coax fix on spacecraft 103, 104, and 106.

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