Faults in wiring systems are a serious concern for the aerospace and aeronautic (commercial, military, and civil) 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. Lunar/Martian dust has been identified as a significant challenge in future exploration missions. Development of dust mitigation technologies that can either be retrofitted to existing aerospace standard electrical connectors (i.e. Amphenol Astronaut Zero-G or MIL-DLT-38999) or incorporated into new designs is vital. In the dusty lunar environment, astronauts will be making and breaking various connections with gloved hands.
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 use of removable caps is a common approach for preventing dust and dirt from entering connectors when electrical cables or fluid lines are detached. However, caps that are not in use can accumulate dust and/or be misplaced. In high-dust environments, where cable or line reliability is critical, these issues can be especially problematic.
NASA Technology Needs
NASA is seeking electrical connector concepts combining dust mitigation strategies and cable diagnostic technologies that will have significant application for lunar and Martian surface systems, as well as for dusty terrestrial applications.
NASA also seeks a dust-tolerant fluids connector that must be able to transfer cryogenic fluids such as liquid oxygen, liquid hydrogen, liquid helium, or liquid nitrogen without leaking. Dust intrusion is very likely to cause a leak path on a connector seal, so the best way of preventing this is to keep the dust off the seals at all times.
NASA is seeking ways to keep connectors clean while in a mated configuration or while separated in two halves. Leak detection methods incorporated into the design would also be of high value.
NASA has identified several additional features they would like to include in the Dust-Mitigation Connector:
• Versatility — Designed for use on electrical cables or fluid lines (liquids or gases)
• Scalability — Sized for use by astronauts wearing gloves, but can be scaled down for use with smaller cable/line sizes and diameters
• Intelligence – Detect, identify, and locate circuit faults in electrical cables
• Robustness — Anticipated to have a lifetime of 5 to 10 years in high-dust environments
• Ruggedness — Designed to withstand being run over by a vehicle
• Ease of use — Designed for quick and easy attachment/detachment by a person wearing bulky gloves
• Affordability — Anticipated to cost less than $275
Initial work on these connectors has been done at the John F. Kennedy Space Center by NASA’s Dr. Carlos Calle, Adam Dokos, Mark Lewis, Jose Perotti, and Robert Mueller, with support from ASRC Aerospace’s Ivan Townsend, Dr. Pedro Medelius, Dr. Gary Bastin, Dr. Chris Immer, and Jeffrey Carlson.