Project Description: 

Major: BS Aerospace Engineering Company: Swales Mentor: Chris Lashley Code: 543 - Mechanical Engineering

The Reinforced Carbon-Carbon (RCC) Repair Tools
Project serves to provide Extra Vehicular Activity (EVA) crew aids and tools to facilitate RCC repair operations. The EVA Thermal Sensor (ETS) is comprised of a commercial off-the-shelf (COTS) Digital Thermometer and a COTS thermocouple surface probe minimally modified and repackaged in an aluminum housing for EVA use. The ETS assembly is enclosed in a seven layer MLI/beta cloth blanket for passive thermal control. The NOAX/crack repair material used in the repair of the RCC surfaces of the Space Shuttle Orbiter Thermal Protection System (TPS) has a defined workable range of 40 degrees F to 100 degrees F during EVA repair operations. The ETS provides the means to measure the surface temperature of the RCC, cracked SiC coating on the RCC, SiC coating with Type A sealant, and the Crack Repair Palette (CRP) during EVA TPS repair. The temperature data from the ETS, the ground thermal analyses, and observations and evaluation of the EVA crewmembers are used to determine the appropriate time in the shuttle orbital cycle to perform TPS repairs.

Contribution:

Andrew’s contribution to the project was to assist with making changes to the EVA Thermal Sensor. During this process the rigid Probe Assembly was replaced with COTS flexible metal tubing. The Probe Assembly was redesigned to provide a flexible extension for the probe so that it could be manipulated and become easier to use. Andrew worked on testing samples to make sure they would operate correctly while in space. As the flexible tubing was made of two materials with different thermal expansion coefficients, there was concern that, at the temperature extremes the different thermal expansion coefficients would cause the materials to expand or contract at different rates causing the tubing to become inflexible. To make sure this would not happen, samples were tested at hot and cold temperature extremes. There was also concern that, in the vacuum of space the flexible neck would experience outgasing, thus increasing the friction between the two materials resulting in lockup. Vacuum testing was performed to ensure that the part would work correctly. Andrew assisted in performing these tests and in analyzing the results. He was also involved in developing a mathematical model to predict how the probe assembly would react when loads were applied.