Mr. Melvin began working in the Fiber Optic Sensors group of the Nondestructive Evaluation Sciences Branch at NASA Langley Research Center in 1989 where he conducted research in the area of physical measurements for the development of advanced instrumentation for Nondestructive Evaluation (NDE). His responsibilities included using optical fiber sensors to measure strain, temperature, and chemical damage in both composite and metallic structures. Additional projects included developing optical interferometric techniques for quantitative determination of damage in aerospace structures and materials. In 1994 Mr. Melvin was selected to lead the Vehicle Health Monitoring (VHM) team for the cooperative Lockheed/NASA X-33 Reuseable Launch Vehicle (RLV) program. The team developed distributed fiber optic strain, temperature and hydrogen sensors for the reduction of vehicle operational costs and to monitor composite liquid oxygen tank and cryogenic insulation performance.
In 1996 Mr. Melvin codesigned and monitored construction of an optical NDE facility capable of producing in-line fiber optic Bragg grating strain sensors at rates in excess of 1000 per hour. This facility will provide a means for performing advanced sensor and laser research for development of aerospace and civil health monitoring systems.
Selected by NASA JSC in June 1998, he reported for training in August 1998. Astronaut Candidate Training includes orientation briefings and tours, numerous scientific and technical briefings, intensive instruction in Shuttle and International Space Station systems, physiological training and ground school to prepare for T-38 flight training, as well as learning water and wilderness survival techniques. Following a period of training and evaluation, he will receive technical assignments within the Astronaut Office before being assigned to a space flight.