ASU scientists and engineers building the Europa Thermal Emission Imaging System (E-THEMIS) for NASA’s Europa Clipper passed a major hurdle recently by capturing the first successful test images, known as “first light” images, from this complex infrared camera.
E-THEMIS, which is led by Regents Professor Philip Christensen of Arizona State University’s School of Earth and Space Exploration, is an infrared camera designed to map Europa’s temperatures for the mission. These infrared images will help scientists seek clues about Europa’s activity, including regions where liquid water may be near the surface.
The “first light” E-THEMIS camera test images were taken from the rooftop of the Interdisciplinary Science and Technology Building 4 (ISTB4) on the ASU Tempe campus using a specially designed mobile cleanroom laboratory, which kept the camera safe from dust, microbes and aerosol particles.
One of the most spectacular test images produced from E-THEMIS is a temperature image taken looking north from ISTB4. In stunning detail, the image clearly shows ASU’s Sun Devil Stadium and “A” Mountain, among other recognizable ASU landmarks. It is even possible to read details inside the stadium from the E-THEMIS instrument, based on temperature differences sensed from about 1.1 km (0.7 miles) away.
During this test, the E THEMIS team also collected temperature images throughout the afternoon and early evening. When displayed in color, these images reveal how the temperature changes as evening approaches. The red, orange and yellow colors in the images indicate warmer temperatures due to heat and the infrared radiation being emitted. The purples and dark blues indicate cooler temperatures, with less heat and infrared radiation emitted.
While the temperatures are approximations during this testing phase, the progression of cooler colors (purples and blues) from afternoon to evening in the three images, acquired at 12:40 p.m. (top), at 4:40 p.m. (middle), and 6:20 p.m. after sunset (bottom), illustrate how the infrared camera detected surface temperatures transitioning from warmer in the afternoon to cooler after sunset.
With this successful “first light” testing of E-THEMIS, the next step for the team is to begin the environmental testing to ensure that E-THEMIS will survive launch and operate as intended in space.