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By NASA
7 min read
A New Alloy is Enabling Ultra-Stable Structures Needed for Exoplanet Discovery
A unique new material that shrinks when it is heated and expands when it is cooled could help enable the ultra-stable space telescopes that future NASA missions require to search for habitable worlds.
Advancements in material technologies are needed to meet the science needs of the next great observatories. These observatories will strive to find, identify, and study exoplanets and their ability to support life. Credit: NASA JPL One of the goals of NASA’s Astrophysics Division is to determine whether we are alone in the universe. NASA’s astrophysics missions seek to answer this question by identifying planets beyond our solar system (exoplanets) that could support life. Over the last two decades, scientists have developed ways to detect atmospheres on exoplanets by closely observing stars through advanced telescopes. As light passes through a planet’s atmosphere or is reflected or emitted from a planet’s surface, telescopes can measure the intensity and spectra (i.e., “color”) of the light, and can detect various shifts in the light caused by gases in the planetary atmosphere. By analyzing these patterns, scientists can determine the types of gasses in the exoplanet’s atmosphere.
Decoding these shifts is no easy task because the exoplanets appear very near their host stars when we observe them, and the starlight is one billion times brighter than the light from an Earth-size exoplanet. To successfully detect habitable exoplanets, NASA’s future Habitable Worlds Observatory will need a contrast ratio of one to one billion (1:1,000,000,000).
Achieving this extreme contrast ratio will require a telescope that is 1,000 times more stable than state-of-the-art space-based observatories like NASA’s James Webb Space Telescope and its forthcoming Nancy Grace Roman Space Telescope. New sensors, system architectures, and materials must be integrated and work in concert for future mission success. A team from the company ALLVAR is collaborating with NASA’s Marshall Space Flight Center and NASA’s Jet Propulsion Laboratory to demonstrate how integration of a new material with unique negative thermal expansion characteristics can help enable ultra-stable telescope structures.
Material stability has always been a limiting factor for observing celestial phenomena. For decades, scientists and engineers have been working to overcome challenges such as micro-creep, thermal expansion, and moisture expansion that detrimentally affect telescope stability. The materials currently used for telescope mirrors and struts have drastically improved the dimensional stability of the great observatories like Webb and Roman, but as indicated in the Decadal Survey on Astronomy and Astrophysics 2020 developed by the National Academies of Sciences, Engineering, and Medicine, they still fall short of the 10 picometer level stability over several hours that will be required for the Habitable Worlds Observatory. For perspective, 10 picometers is roughly 1/10th the diameter of an atom.
NASA’s Nancy Grace Roman Space Telescope sits atop the support structure and instrument payloads. The long black struts holding the telescope’s secondary mirror will contribute roughly 30% of the wave front error while the larger support structure underneath the primary mirror will contribute another 30%.
Credit: NASA/Chris Gunn
Funding from NASA and other sources has enabled this material to transition from the laboratory to the commercial scale. ALLVAR received NASA Small Business Innovative Research (SBIR) funding to scale and integrate a new alloy material into telescope structure demonstrations for potential use on future NASA missions like the Habitable Worlds Observatory. This alloy shrinks when heated and expands when cooled—a property known as negative thermal expansion (NTE). For example, ALLVAR Alloy 30 exhibits a -30 ppm/°C coefficient of thermal expansion (CTE) at room temperature. This means that a 1-meter long piece of this NTE alloy will shrink 0.003 mm for every 1 °C increase in temperature. For comparison, aluminum expands at +23 ppm/°C.
While other materials expand while heated and contract when cooled, ALLVAR Alloy 30 exhibits a negative thermal expansion, which can compensate for the thermal expansion mismatch of other materials. The thermal strain versus temperature is shown for 6061 Aluminum, A286 Stainless Steel, Titanium 6Al-4V, Invar 36, and ALLVAR Alloy 30.
Because it shrinks when other materials expand, ALLVAR Alloy 30 can be used to strategically compensate for the expansion and contraction of other materials. The alloy’s unique NTE property and lack of moisture expansion could enable optic designers to address the stability needs of future telescope structures. Calculations have indicated that integrating ALLVAR Alloy 30 into certain telescope designs could improve thermal stability up to 200 times compared to only using traditional materials like aluminum, titanium, Carbon Fiber Reinforced Polymers (CFRPs), and the nickel–iron alloy, Invar.
The hexapod assembly with six ALLVAR Alloy struts was measured for long-term stability. The stability of the individual struts and the hexapod assembly were measured using interferometry at the University of Florida’s Institute for High Energy Physics and Astrophysics. The struts were found to have a length noise well below the proposed target for the success criteria for the project. Credit: (left) ALLVAR and (right) Simon F. Barke, Ph.D. To demonstrate that negative thermal expansion alloys can enable ultra-stable structures, the ALLVAR team developed a hexapod structure to separate two mirrors made of a commercially available glass ceramic material with ultra-low thermal expansion properties. Invar was bonded to the mirrors and flexures made of Ti6Al4V—a titanium alloy commonly used in aerospace applications—were attached to the Invar. To compensate for the positive CTEs of the Invar and Ti6Al4V components, an NTE ALLVAR Alloy 30 tube was used between the Ti6Al4V flexures to create the struts separating the two mirrors. The natural positive thermal expansion of the Invar and Ti6Al4V components is offset by the negative thermal expansion of the NTE alloy struts, resulting in a structure with an effective zero thermal expansion.
The stability of the structure was evaluated at the University of Florida Institute for High Energy Physics and Astrophysics. The hexapod structure exhibited stability well below the 100 pm/√Hz target and achieved 11 pm/√Hz. This first iteration is close to the 10 pm stability required for the future Habitable Worlds Observatory. A paper and presentation made at the August 2021 Society of Photo-Optical Instrumentation Engineers conference provides details about this analysis.
Furthermore, a series of tests run by NASA Marshall showed that the ultra-stable struts were able to achieve a near-zero thermal expansion that matched the mirrors in the above analysis. This result translates into less than a 5 nm root mean square (rms) change in the mirror’s shape across a 28K temperature change.
The ALLVAR enabled Ultra-Stable Hexapod Assembly undergoing Interferometric Testing between 293K and 265K (right). On the left, the Root Mean Square (RMS) changes in the mirror’s surface shape are visually represented. The three roughly circular red areas are caused by the thermal expansion mismatch of the invar bonding pads with the ZERODUR mirror, while the blue and green sections show little to no changes caused by thermal expansion. The surface diagram shows a less than 5 nanometer RMS change in mirror figure. Credit: NASA’s X-Ray and Cryogenic Facility [XRCF] Beyond ultra-stable structures, the NTE alloy technology has enabled enhanced passive thermal switch performance and has been used to remove the detrimental effects of temperature changes on bolted joints and infrared optics. These applications could impact technologies used in other NASA missions. For example, these new alloys have been integrated into the cryogenic sub-assembly of Roman’s coronagraph technology demonstration. The addition of NTE washers enabled the use of pyrolytic graphite thermal straps for more efficient heat transfer. ALLVAR Alloy 30 is also being used in a high-performance passive thermal switch incorporated into the UC Berkeley Space Science Laboratory’s Lunar Surface Electromagnetics Experiment-Night (LuSEE Night) project aboard Firefly Aerospace’s Blue Ghost Mission 2, which will be delivered to the Moon through NASA’s CLPS (Commercial Lunar Payload Services) initiative. The NTE alloys enabled smaller thermal switch size and greater on-off heat conduction ratios for LuSEE Night.
Through another recent NASA SBIR effort, the ALLVAR team worked with NASA’s Jet Propulsion Laboratory to develop detailed datasets of ALLVAR Alloy 30 material properties. These large datasets include statistically significant material properties such as strength, elastic modulus, fatigue, and thermal conductivity. The team also collected information about less common properties like micro-creep and micro-yield. With these properties characterized, ALLVAR Alloy 30 has cleared a major hurdle towards space-material qualification.
As a spinoff of this NASA-funded work, the team is developing a new alloy with tunable thermal expansion properties that can match other materials or even achieve zero CTE. Thermal expansion mismatch causes dimensional stability and force-load issues that can impact fields such as nuclear engineering, quantum computing, aerospace and defense, optics, fundamental physics, and medical imaging. The potential uses for this new material will likely extend far beyond astronomy. For example, ALLVAR developed washers and spacers, are now commercially available to maintain consistent preloads across extreme temperature ranges in both space and terrestrial environments. These washers and spacers excel at counteracting the thermal expansion and contraction of other materials, ensuring stability for demanding applications.
For additional details, see the entry for this project on NASA TechPort.
Project Lead: Dr. James A. Monroe, ALLVAR
The following NASA organizations sponsored this effort: NASA Astrophysics Division, NASA SBIR Program funded by the Space Technology Mission Directorate (STMD).
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Last Updated Jul 01, 2025 Related Terms
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By European Space Agency
Video: 00:01:38 On 11 June, engineers at OHB’s facilities in Germany joined together the two main parts of ESA’s Plato mission.
They used a special crane to lift Plato’s payload module, housing its 26 ultra-sensitive cameras, into the air and carefully line it up over the service module. The supporting service module contains everything else that the spacecraft needs to function, including subsystems for power, propulsion and communication with Earth.
With millimetre-level precision, the engineers gently lowered the payload module into place. Once perfectly positioned, the team tested the electrical connections.
Finally, they securely closed a panel that connects the payload module to the service module both physically and electronically (seen ‘hanging’ horizontally above the service module in this image). This panel, which opens and closes with hinges, also contains the electronics to process data from the cameras.
Now in one piece, Plato is one step closer to beginning its hunt for Earth-like planets.
In the coming weeks, the spacecraft will undergo tests to ensure its cameras and data processing systems still work perfectly.
Then it will be driven from OHB’s cleanrooms to ESA’s technical heart (ESTEC) in the Netherlands. At ESTEC, engineers will complete the spacecraft by fitting it with a combined sunshield and solar panel module.
Following a series of essential tests to confirm that Plato is fit for launch and ready to work in space, it will be shipped to Europe’s launch site in French Guiana.
The mission is scheduled to launch on an Ariane 6 in December 2026.
Access the related broadcast quality video footage.
ESA’s Plato (PLAnetary Transits and Oscillations of stars) will use 26 cameras to study terrestrial exoplanets in orbits up to the habitable zone of Sun-like stars.
Plato's scientific instrumentation, consisting of the cameras and electronic units, is provided through a collaboration between ESA and the Plato Mission Consortium. This Consortium is composed of various European research centres, institutes and industries, led by the German Aerospace Center (DLR). The spacecraft is being built and assembled by the industrial Plato Core Team led by OHB together with Thales Alenia Space and Beyond Gravity.
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By European Space Agency
Video: 00:04:13 Daniel Neuenschwander, ESA head of Space and Robotic Exploration, explains that Ignis mission will include an ambitious technological and scientific programme with several experiments led by ESA and proposed by the Polish space industry.
On 26 June 2025, ESA project astronaut Sławosz Uznański-Wiśniewski from Poland and his crewmates arrived to the International Space Station on the Axiom-4 mission (Ax-4).
The Polish project astronaut is the second of a new generation of European astronauts to fly on a commercial human spaceflight opportunity with Axiom Space.
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By European Space Agency
Asteroid 2024 YR4 made headlines earlier this year when its probability of impacting Earth in 2032 rose as high as 3%. While an Earth impact has now been ruled out, the asteroid’s story continues.
The final glimpse of the asteroid as it faded out of view of humankind’s most powerful telescopes left it with a 4% chance of colliding with the Moon on 22 December 2032.
The likelihood of a lunar impact will now remain stable until the asteroid returns to view in mid-2028. In this FAQ, find out why we are left with this lingering uncertainty and how ESA's planned NEOMIR space telescope will help us avoid similar situations in the future.
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Since childhood, Derrick Bailey always had an early fascination with aeronautics. Military fighter jet pilots were his childhood heroes, and he dreamed of joining the aerospace industry. This passion was a springboard into his 17-year career at NASA, where Bailey plays an important role in enabling successful rocket launches.
Bailey is the Launch Vehicle Certification Manager in the Launch Services Program (LSP) within the Space Operations Mission Directorate. In this role, he helps NASA outline the agency’s risk classifications of new rockets from emerging and established space companies.
“Within my role, I formulate a series of technical and process assessments for NASA LSP’s technical team to understand how companies operate, how vehicles are designed and qualified, and how they perform in flight,” Bailey said.
Beyond technical proficiency and readiness, a successful rocket launch relies on establishing a strong foundational relationship between NASA and the commercial companies involved. Bailey and his team ensure effective communication with these companies to provide the guidance, data, and analysis necessary to support them in overcoming challenges.
“We work diligently to build trusting relationships with commercial companies and demonstrate the value in partnering with our team,” Bailey said.
Bailey credits a stroke of fate that landed him at the agency. During his senior year at Georgia Tech, where he was pursuing a degree in aerospace engineering, Bailey almost walked past the NASA tent at a career fair. However, he decided to grab a NASA sticker and strike up a conversation, which quickly turned into an impromptu interview. He walked away that day with a job offer to work on the now-retired Space Shuttle Program at the agency’s Kennedy Space Center in Florida.
“I never imagined working at NASA,” Bailey said. “Looking back, it’s unbelievable that a chance encounter resulted in securing a job that has turned into an incredible career.”
Thinking about the future, Bailey is excited about new opportunities in the commercial space industry. Bailey sees NASA as a crucial advisor and mentor for commercial sector while using industry capabilities to provide more cost-effective access to space.
Derrick Bailey, launch vehicle certification manager for NASA’s Launch Services Program
“We are the enablers,” Bailey said of his role in the directorate. “It is our responsibility to provide the best opportunity for future explorers to begin their journey of discovery in deep space and beyond.”
Outside of work, Bailey enjoys spending time with his family, especially his two sons, who keep him busy with trips to the baseball diamond and homework sessions. Bailey also enjoys hands-on activities, like working on cars, off-road vehicles, and house projects – hobbies he picked up from his mechanically inclined father. Additionally, at the beginning of 2025, his wife accepted a program specialist position with LSP, an exciting development for the entire Bailey family.
“One of my wife’s major observations early on in my career was how much my colleagues genuinely care about one another and empower people to make decisions,” Bailey explained. “These are the things that make NASA the number one place to work in the government.”
NASA’s Space Operations Mission Directorate maintains a continuous human presence in space for the benefit of people on Earth. The programs within the directorate are the hub of NASA’s space exploration efforts, enabling Artemis, commercial space, science, and other agency missions through communication, launch services, research capabilities, and crew support.
To learn more about NASA’s Space Operation Mission Directorate, visit:
https://www.nasa.gov/directorates/space-operations
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Last Updated Jun 26, 2025 Related Terms
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