Qualification of Bonding Process of Temperature Sensors to Extreme Temperature Deep Space Missions**
A process has been explored based on state of the art technology to bond a platinum resistance thermometer (PRT) on potential aerospace materials such as a flat aluminum surface and a flexible copper tube to simulate coaxial cable for flight applications. Primarily, PRTs were inserted into a metal plated copper braid to avoid stresses on the sensor while attaching the sensor with braid to the base material for long duration deep space missions. Appropriate pretreatment has been implemented in this study to enhance the adhesion of the PRTs to the base material. The NuSil product was chosen in this research to attach the PRT to the base materials. The resistance (∼1.1 kΩ) of PRTs was continuously electrically monitored during the qualification thermal cycling testing from −150°C to +120°C and −100°C to −35°C. The test hardware was thermal cycled three times the mission life per JPL design principles for the JUNO project. No PRT failures were observed during and after the PRT thermal cycling qualification test for extreme temperature environments. However, there were some failures associated with staking of the PRT pigtails as a result of the thermal cycling qualification test.