"Durometers, otherwise known as hardness gauges, are used to measure the hardness of non-metallic materials, such as rubber, plastic, foam, and wood. A durometer works by measuring the penetration of the gauges into the material being tested.
The Rex Gauge Company worked with engineers at Lockheed Martin and NASA to develop a custom durometer, which could be used by astronauts to test an experimental repair technique for thermal protection tiles damaged during lift off.
The challenge was to create a gauge that could endure the extreme conditions of outer space while remaining simple for astronauts to use while in bulky space suits.
The final product, gauge model SG-5000, was approved by NASA and had to pass rigorous testing to prove it could withstand the vacuum and extreme temperatures of space ranging from negative 150 degrees to plus 150 degrees Fahrenheit. While some components were derived from standard durometers, the SG-5000 featured a custom lightweight ventilated housing with an extra large dial for easy readability and a special finish to allow the gauge to be handled in extreme temperature ranges.
The SG-5000 durometer as pictured was flown aboard the Space Shuttle Discovery during Mission STS-114 on July 26th, 2005. The Rex Gauge team is extremely proud to be a contributor in the NASA Return to Flight effort and the Space Foundation is proud to have Rex Gauge Company as a partner in the Space Certification Program."