Faults in wiring systems are a serious concern for the aerospace and aeronautic (commercial, military, and civilian) industries. Circuit failures and vehicle accidents have occurred and have been attributed to faulty wiring created by open and/or short circuits. Often, such circuit failures occur due to vibration during vehicle launch or operation. Therefore, developing non-intrusive fault-tolerant techniques is necessary to detect circuit faults and automatically route signals through alternate recovery paths while the vehicle or lunar surface systems equipment is in operation. Electrical connector concepts combining dust mitigation strategies and cable diagnostic technologies have significant application for lunar and Martian surface systems, as well as for dusty terrestrial applications.

By creating intelligent electrical connectors that detect, identify, and locate circuit faults and that then bypass damaged conductors and route to available spares, the detection of connector failures is improved, and it becomes possible to recover from mission-threatening circuit faults and failures. Three styles of electrical connector concepts for use in zero-gravity and reduced-gravity dusty environments were developed: conventional connector systems with protective dust barriers, contactless connector systems, and smooth connector systems. The conventional connector with protective dust barrier mitigates dust by incorporating a physical dust shield. These dust barriers may be retrofitted to existing military or International Space Station connectors. Alternatively, it is possible to utilize existing connectors that can be incorporated into a universal connector housing. Contactless connectors have advantages over conventional connectors where environment integrity poses a design constraint.

The dust-tolerant intelligent electrical connection system has several novel concepts and unique features. It combines intelligent cable diagnostics (health monitoring) and automatic circuit routing capabilities into a dust-tolerant electrical umbilical. It retrofits a clamshell protective dust cover to an existing connector for reduced gravity operation, and features a universal connector housing with three styles of dust protection: inverted cap, rotating cap, and clamshell. It uses a self-healing membrane as a dust barrier for electrical connectors where required, while also combining lotus leaf technology for applications where a dust-resistant coating providing low surface tension is needed to mitigate Van der Waals forces, thereby disallowing dust particle adhesion to connector surfaces. It also permits using a ruggedized iris mechanism with an embedded electrodynamic dust shield as a dust barrier for electrical connectors where required.

The system also can use a coating to repel lunar dust and self-clean the surface, and incorporates cable health monitoring and automatic routing capabilities into an inductively coupled or capacitively coupled contactless electrical connector. An innovative knob and donut type connector is also included to mitigate lunar dust challenges. Adding electrodynamic dust shields is also possible where needed to combine active dust mitigation with EMI (electromagnetic interference) shielding capability.

This work was done by Mark Lewis, Adam Dokos, Jose Perotti, Carlos Calle, and Robert Mueller of Kennedy Space Center; and Gary Bastin, Jeffrey Carlson, Ivan Townsend III, Christopher Immer, and Pedro Medelius of ASRC Aerospace Corporation. For more information, contact the Kennedy Space Center Innovative Partnerships Office at (321) 867- 5033. KSC-13578


NASA Tech Briefs Magazine

This article first appeared in the February, 2012 issue of NASA Tech Briefs Magazine.

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