A new material with unique negative thermal expansion properties has been developed to help enable ultra-stable space telescopes that can search for habitable worlds beyond our solar system. The material, known as ALLVAR Alloy 30, shrinks when heated and expands when cooled, making it ideal for compensating for the thermal expansion mismatch of other materials in telescope structures.
Currently, scientists and engineers face challenges such as micro-creep, thermal expansion, and moisture expansion that affect telescope stability. Although materials used in telescopes have improved dimensional stability, they still fall short of the 10 picometer level stability required for future NASA missions like the Habitable Worlds Observatory.
Researchers from ALLVAR developed a hexapod structure to demonstrate the effectiveness of negative thermal expansion alloys. The structure featured an NTE alloy tube between flexures made of titanium alloy and bonded Invar mirrors, resulting in an effective zero thermal expansion. Stability evaluations showed that the structure achieved stability well below the target 100 pm/√Hz and even surpassed the requirement with a value of 11 pm/√Hz.
The new material has also enabled enhanced passive thermal switch performance and has been used to remove the effects of temperature changes on bolted joints and infrared optics. Its applications may extend beyond space missions, such as in nuclear engineering, quantum computing, aerospace and defense, optics, fundamental physics, and medical imaging.
Additionally, ALLVAR is developing a new alloy with tunable thermal expansion properties that can match other materials or achieve zero CTE. This material will have significant implications for various industries, including space exploration, and has the potential to revolutionize fields beyond astronomy.
Source: https://science.nasa.gov/science-research/science-enabling-technology/technology-highlights/a-new-alloy-is-enabling-ultra-stable-structures-needed-for-exoplanet-discovery