For many years, NASA was aware of and investigating, the potential use of ultrasound condition based monitoring technology. There were several investigations of available products, as well as a unit developed by NASA itself. However, once introduced to the CTRL UL101, a review panel that included astronauts were impressed with the UL101's sensitivity, size, and ease of operation. CTRL Systems, Inc. designed and built a "space hardened" UL101 for NASA within 30 days of the first meeting. The new UL101 was vigorously tested by NASA for spaceflight durability, safety, and performance and passed all of the tests on the first trial, something that a majority of products fail to achieve.
The first UL101 was delivered to NASA in 2001 to test and verify that there were no leaks during an installation of an airlock. Since then, the UL101 has been used for leak detection and general diagnostics. This picture shows astronauts using the UL101 to develop a Non Destructive Evaluation (NDE) inspection program for reinforced carbon-carbon composite components (RCC).