Application of additive manufacturing in developing smoke and flame detectors for a habitable microgravity environment

A fire event is highly hazardous for microgravity habitable environment in space due to confined volume of crew module and limited mitigation resources. The complex electric circuitry in crew module are the predominant cause of fire initiation and its early detection could prevent catastrophic fire spread. Smoke and flame detectors are two such sensing instruments for early detection and preventing major fire incidents. Development of these sensors with design constraints of compactness, light weight and intricate geometries are challenging to comply stringent project schedules. Additive manufacturing being an advantages technique to develop intricate complex geometries are carefully chosen to design and develop these sensors which gave us advantages of design flexibility of achieving two parts consolidated assembly as compared to 5–8 parts assembly developed by conventional manufacturing methods. Substantial mass and volume savings are achieved which are more than 34% and 15% respectively. This study is further compared with developed smoke detector for Orion Crew Exploration Vehicle (CEV)- NASA and established the facts of mass and size saving. The space worthiness of both subsystems are evaluated by functional and space environmental test specifications. The designs are quite stiff to achieve natural frequencies of the order of 1000 Hz to establish the structural integrity of sensors for bearing launch vibration loads. The functional aspects of these sensors are evaluated as per available standard UL217/UL268 for smoke detector and sensitivity parameters (size of fire, distance, field of view and electric spark) for flame sensor which are found quite satisfactory. Thus, the development potential using additive manufacturing proved a noteworthy use case for development of smoke and flame sensor for space environment.