NASA tests shrinking metals to help it find more exoplanets
- Reference: 1751441585
- News link: https://www.theregister.co.uk/2025/07/02/nasa_negative_thermal_expansion_alloy_tests/
- Source link:
Readers doubtless know that metals expand when heated. As explained in a NASA [1]blog post that’s a problem for space telescopes because if their components warm and expand it can mean that the shape of their mirrors change in ways that make it harder to conduct observations.
NASA has already developed materials that compensate for those effects and used them in the James Webb Space Telescope and in the Nancy Grace Roman Space Telescope that the aerospace agency intends to launch in 2027.
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The HBO, NASA’s next space ‘scope project after the Nancy Grace Roman, will need even more resilient materials.
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To understand why, the post explains how to observe exoplanets.
“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 gases in the exoplanet’s atmosphere.”
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Observing those shifts is no easy matter, “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.”
That means the Habitable Worlds Observatory “will need a contrast ratio of one to one billion (1:1,000,000,000).”
To achieve that contrast ratio, the HBO will need to be 1,000 times more stable than the James Webb telescope.
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Which is why NASA scientists and a company called ALLVAR are investigating a “negative thermal expansion” (NTE) alloy that shrinks when heated.
According to NASA’s post, “A 1-meter-long piece of this NTE alloy will shrink 0.003 mm for every 1° C increase in temperature.”
“Because it shrinks when other materials expand, ALLVAR Alloy 30 can be used to strategically compensate for the expansion and contraction of other materials,” NASA’s post states.
[7]1.5 TB of James Webb Space Telescope data just hit the internet
[8]ESA's XMM-Newton finds huge filament of missing matter
[9]Hubble Space Telescope is still producing science at 35
[10]Is NASA's science budget heading for a black hole?
Tests have delivered promising results: ALLVAR apparently built a test mirror mounted on struts of a titanium alloy that expands when heated and struts made with Alloy 30. Both alloys performed as expected, with Alloy 30 offsetting the expansion in the titanium alloy to produce a stable mirror.
NASA thinks the tests also showed Alloy 30 “enabled enhanced passive thermal switch performance and has been used to remove the detrimental effects of temperature changes on bolted joints and infrared optics.”
Space boffins are therefore considering how to use Alloy 30 in many other space scenarios.
You might want to consider using it, too, as NASA wrote “ALLVAR developed washers and spacers are now commercially available to maintain consistent preloads across extreme temperature ranges in both space and terrestrial environments.” ®
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[1] https://science.nasa.gov/science-research/science-enabling-technology/technology-highlights/a-new-alloy-is-enabling-ultra-stable-structures-needed-for-exoplanet-discovery/
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aGUDMWvezRhbIonpHrXOuQAAAwY&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aGUDMWvezRhbIonpHrXOuQAAAwY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aGUDMWvezRhbIonpHrXOuQAAAwY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[5] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aGUDMWvezRhbIonpHrXOuQAAAwY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aGUDMWvezRhbIonpHrXOuQAAAwY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[7] https://www.theregister.com/2025/06/09/jwst_open_science_data/
[8] https://www.theregister.com/2025/06/19/esas_xmmnewton_finds_filaments/
[9] https://www.theregister.com/2025/04/25/hubble_space_scope_35/
[10] https://www.theregister.com/2025/03/11/nasa_science_budget_comment/
[11] https://whitepapers.theregister.com/
Re: A new way to solve an old problem?
Indeed, just with much higher requirements for stability than any pendulum clock probably ever had.
Re: A new way to solve an old problem?
Had a vision of the HBO launching in a finely carved teak longcase, with mahogany and walnut details.
The next step on from the Japanese LignoSat.
Re: A new way to solve an old problem?
Bob Shaw [1]got there first
[1] https://www.goodreads.com/book/show/883712.The_Wooden_Spaceships
Re: A new way to solve an old problem?
The ghost of Brian Aldiss [1]would like a quiet word about going the all-natural route to arboreal orbiters.
Can somebody shush those norn? No, Skuld, Yggdrasil isn't in orbit, that's why. Yes, yes, you can climb it to reach the heavens. Look, I think we may be getting off topic here, just go and stop Ratatoskr burying another asteroid, please.
[1] https://en.wikipedia.org/wiki/Hothouse_(novel)
The Allvar name looks to be a riff on Invar, an alloy with an unusually low, but still slightly positive coefficient of thermal expansion that has been around since the 19th century. Often used in situations where making something temperature insensitive is important. Though not as important as in an exoplanet hunting space telescope.
“ALLVAR developed washers and spacers are now commercially available to maintain consistent preloads across extreme temperature ranges in both space and terrestrial environments.”
Does it work in high stress environments? If so, I can see several uses for it in high performance engines.
They have ways around the expansion problem anyway. Formula 1 engines have to be pre-heated to run.
Does this "alloy" involve maybe hydrogen, oxygen, and not much else...?
A new way to solve an old problem?
Pendulum clocks use a similar technique (with +ve temperature co-efficient materials) to stop temperature changes from altering the rate at which the pendulum swings.