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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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Explore This Section Exoplanets Home Exoplanets Overview Exoplanets Facts Types of Exoplanets Stars What is the Universe Search for Life The Big Questions Are We Alone? Can We Find Life? The Habitable Zone Why We Search Target Star Catalog Discoveries Discoveries Dashboard How We Find and Characterize Missions People Exoplanet Catalog Immersive The Exoplaneteers Exoplanet Travel Bureau 5 Ways to Find a Planet Strange New Worlds Universe of Monsters Galaxy of Horrors News Stories Blog Resources Get Involved Glossary Eyes on Exoplanets Exoplanet Watch More Multimedia ExEP Artist’s concept of a planet orbiting two brown dwarfs. The planet is in a polar orbit (red), perpendicular to the mutual orbit of the two brown dwarfs (blue). ESO/L. Calçada The Discovery
A newly discovered planetary system, informally known as 2M1510, is among the strangest ever found. An apparent planet traces out an orbit that carries it far over the poles of two brown dwarfs. This pair of mysterious objects – too massive to be planets, not massive enough to be stars – also orbit each other. Yet a third brown dwarf orbits the other two at an extreme distance.
Key Facts
In a typical arrangement, as in our solar system, families of planets orbit their parent stars in more-or-less a flat plane – the orbital plane – that matches the star’s equator. The rotation of the star, too, aligns with this plane. Everyone is “coplanar:” flat, placid, stately.
Not so for possible planet 2M1510 b (considered a “candidate planet” pending further measurements). If confirmed, the planet would be in a “polar orbit” around the two central brown dwarfs – in other words, its orbital plane would be perpendicular to the plane in which the two brown dwarfs orbit each other. Take two flat disks, merge them together at an angle in the shape of an X, and you have the essence of this orbital configuration.
“Circumbinary” planets, those orbiting two stars at once, are rare enough. A circumbinary orbiting at a 90-degree tilt was, until now, unheard of. But new measurements of this system, using the ESO (European Southern Observatory) Very Large Telescope in Chile, appear to reveal what scientists previously only imagined.
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The method by which the study’s science team teased out the planet’s vertiginous existence is itself a bit of a wild ride. The candidate planet cannot be detected the way most exoplanets – planets around other stars – are found today: the “transit” method, a kind of mini-eclipse, a tiny dip in starlight when the planet crosses the face of its star.
Instead they used the next most prolific method, “radial velocity” measurements. Orbiting planets cause their stars to rock back and forth ever so slightly, as the planets’ gravity pulls the stars one way and another; that pull causes subtle, but measurable, shifts in the star’s light spectrum. Add one more twist to the detection in this case: the push-me-pull-you effect of the planet on the two brown dwarfs’ orbit around each other. The path of the brown dwarf pair’s 21-day mutual orbit is being subtly altered in a way that can only be explained, the study’s authors conclude, by a polar-orbiting planet.
Fun Facts
Only 16 circumbinary planets – out of more than 5,800 confirmed exoplanets – have been found by scientists so far, most by the transit method. Twelve of those were found using NASA’s now-retired Kepler Space Telescope, the mission that takes the prize for the most transit detections (nearly 2,800). Scientists have observed a small number of debris disks and “protoplanetary” disks in polar orbits, and suspected that polar-orbiting planets might be out there as well. They seem at last to have turned one up.
The Discoverers
An international science team led by Thomas A. Baycroft, a Ph.D. student in astronomy and astrophysics at the University of Birmingham, U.K., published a paper describing their discovery in the journal “Science Advances” in April 2025. The planet was entered into NASA’s Exoplanet Archive on May 1, 2025. The system’s full name is 2MASS J15104786-281874 (2M1510 for short).
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Last Updated May 21, 2025 Related Terms
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By NASA
The Axiom Mission 4, or Ax-4, crew will launch aboard a SpaceX Dragon spacecraft to the International Space Station from NASA’s Kennedy Space Center in Florida. From left to right: ESA (European Space Agency) astronaut Sławosz Uznański-Wiśniewski of Poland, former NASA astronaut Peggy Whitson, ISRO (Indian Space Research Organization) astronaut Shubhanshu Shukla, and Tibor Kapu of Hungary.Credit: Axiom Space NASA will join a media teleconference hosted by Axiom Space at 10:30 a.m. EDT, Tuesday, May 20, to discuss the launch of Axiom Mission 4 (Ax-4), the fourth private astronaut mission to the International Space Station.
Briefing participants include:
Dana Weigel, manager, International Space Station Program, NASA Allen Flynt, chief of mission services, Axiom Space Sarah Walker, director, Dragon mission management, SpaceX Sergio Palumberi, mission manager, ESA (European Space Agency) Aleksandra Bukała, project manager, head of strategy and international cooperation, POLSA (Polish Space Agency) Orsolya Ferencz, ministerial commissioner of space research, HUNOR (Hungarian to Orbit) To join the call, media must register with Axiom Space by 12 p.m., Monday, May 19, at:
https://bit.ly/437SAAh
The Ax-4 launch aboard a SpaceX Dragon spacecraft on the company’s Falcon 9 rocket is targeted no earlier than 9:11 a.m., Sunday, June 8, from NASA’s Kennedy Space Center in Florida.
During the mission aboard the space station, a four-person multi-national crew will complete about 60 research experiments developed for microgravity in collaboration with organizations across the globe.
Peggy Whitson, former NASA astronaut and director of human spaceflight at Axiom Space, will command the commercial mission, while ISRO astronaut Shubhanshu Shukla will serve as pilot. The two mission specialists are ESA project astronaut Sławosz Uznański-Wiśniewski of Poland and Tibor Kapu of Hungary.
The first private astronaut mission to the station, Axiom Mission 1, lifted off in April 2022 for a 17-day mission aboard the orbiting laboratory. The second private astronaut mission to the station, Axiom Mission 2, also was commanded by Whitson and launched in May 2023 for eight days in orbit. The most recent private astronaut mission, Axiom Mission 3, launched in January 2024; the crew spent 18 days docked to the space station.
The International Space Station is a springboard for developing a low Earth economy. NASA’s goal is to achieve a strong economy off the Earth where the agency can purchase services as one of many customers to meet its science and research objectives in microgravity. NASA’s commercial strategy for low Earth orbit provides the government with reliable and safe services at a lower cost, enabling the agency to focus on Artemis missions to the Moon in preparation for Mars while also continuing to use low Earth orbit as a training and proving ground for those deep space missions.
Learn more about NASA’s commercial space strategy at:
https://www.nasa.gov/commercial-space
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Claire O’Shea
Headquarters, Washington
202-358-1100
claire.a.o’shea@nasa.gov
Anna Schneider
Johnson Space Center, Houston
281-483-5111
anna.c.schneider@nasa.gov
Alexis DeJarnette
Axiom Space, Houston
alexis@axiomspace.com
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Last Updated May 14, 2025 LocationNASA Headquarters Related Terms
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA’s Curiosity rover appears as a dark speck in this contrast-enhanced view captured on Feb. 28, 2025, by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter. Trailing Curiosity are the rover’s tracks, which can linger on the Martian surface for months before being erased by the wind. NASA/JPL-Caltech/University of Arizona The image marks what may be the first time one of the agency’s Mars orbiters has captured the rover driving.
NASA’s Curiosity Mars rover has never been camera shy, having been seen in selfies and images taken from space. But on Feb. 28 — the 4,466th Martian day, or sol, of the mission — Curiosity was captured in what is believed to be the first orbital image of the rover mid-drive across the Red Planet.
Taken by the HiRISE (High-Resolution Imaging Science Experiment) camera aboard NASA’s Mars Reconnaissance Orbiter, the image shows Curiosity as a dark speck at the front of a long trail of rover tracks. Likely to last for months before being erased by wind, the tracks span about 1,050 feet (320 meters). They represent roughly 11 drives starting on Feb. 2 as Curiosity trucked along at a top speed of 0.1 mph (0.16 kph) from Gediz Vallis channel on the journey to its next science stop: a region with potential boxwork formations, possibly made by groundwater billions of years ago.
How quickly the rover reaches the area depends on a number of factors, including how its software navigates the surface and how challenging the terrain is to climb. Engineers at NASA’s Jet Propulsion Laboratory in Southern California, which leads Curiosity’s mission, work with scientists to plan each day’s trek.
“By comparing the time HiRISE took the image to the rover’s commands for the day, we can see it was nearly done with a 69-foot drive,” said Doug Ellison, Curiosity’s planning team chief at JPL.
Designed to ensure the best spatial resolution, HiRISE takes an image with the majority of the scene in black and white and a strip of color down the middle. While the camera has captured Curiosity in color before, this time the rover happened to fall within the black-and-white part of the image.
In the new image, Curiosity’s tracks lead to the base of a steep slope. The rover has since ascended that slope since then, and it is expected to reach its new science location within a month or so.
More About Curiosity and MRO
NASA’s Curiosity Mars rover was built at JPL, which is managed for the agency by Caltech in Pasadena, California. JPL manages both the Curiosity and Mars Reconnaissance Orbiter missions on behalf of NASA’s Science Mission Directorate in Washington as part of the agency’s Mars Exploration Program portfolio. The University of Arizona, in Tucson, operates HiRISE, which was built by BAE Systems in Boulder, Colorado.
For more about the missions, visit:
science.nasa.gov/mission/msl-curiosity
science.nasa.gov/mission/mars-reconnaissance-orbiter
News Media Contacts
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
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Last Updated Apr 24, 2025 Related Terms
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By European Space Agency
A new wave of ocean scientists has embarked on an extraordinary six-week voyage aboard a majestic tall ship that set sail today from Norway bound for southern France. But this is no ordinary journey.
Thanks to this ESA Advanced Ocean Training Course, these upcoming researchers will be taking a deep dive into ocean science, empowering them with skills to harness satellite data for research, innovation and sustainable development – and preparing them to become tomorrow’s leaders and ambassadors for ocean science.
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