2023-04-28 12:15:36
Astronomy may now be at the dawn of a new technological revolution comparable to that of the invention of the first telescope, thanks to the rise of fluidic telescopes, which can only exist in weightlessness.
The conventional technology with which optical components for telescopes are manufactured is very laborious and difficult to handle. Any small flaw can ruin the job. And the bigger the telescope, the more complicated everything gets. With current technologies, expanding space telescopes to apertures greater than about 10 meters in diameter does not seem feasible. A new telescope concept, in which the optical components would not be solid but fluid, could make it possible to create a space telescope with an aperture of no less than 50 meters in diameter. The aperture of a reflecting optical telescope refers to the size of the telescope’s primary mirror, the surface that collects and focuses incoming light.
Creating a fluidic space telescope with an aperture of 50 meters is the goal of the FLUTE (FLUidic TElescope) project in which NASA (US space agency) and the Israel Institute of Technology (Technion) are working.
Project scientists are working on ways to shape the huge circular fluidic mirrors in space that such telescopes will need. Reflecting telescopes with larger mirrors collect more light, which translates into greater sighting power, allowing distant astronomical objects to be seen in greater detail.
With gigantic fluidic space telescopes like the one that the FLUTE project seeks to build, it would be possible to search for and study planets outside our solar system similar to Earth and potentially habitable, first-generation stars (those that formed directly from the gas created by the Big Bang, the colossal “explosion” with which the universe was born) and many other astronomical objects that until now have only been glimpsed by humanity.
With current astronautic technology, everything launched into space must conform to the size and weight limits imposed by the characteristics of the launchers. The James Webb Space Telescope, with its 6.5 meter diameter aperture, has already exceeded the limits of size and its trip into space had to be folded like an origami figure, including the mirror itself, to fit in the launcher that He transported it into space.
The fluidic space telescope aperture predicted by the FLUTE researchers would be, according to the most recent design, about 50 meters in diameter.
The strategies that were valid for the James Webb Space Telescope could hardly be used for a colossus of that size.
Artist’s impression of a fluidic telescope with an aperture of 50 meters. Fluidic telescopes can only exist in weightlessness. The mirror of this 50-meter telescope would be made in space, from liquid materials sent from Earth. (Image: NASA)
The option on which FLUTE is based is completely different, cheaper and even resistant to defects. The key is that it is based on the natural behavior of fluids in weightlessness (or microgravity).
All liquids have an elastic force that maintains the cohesion of a liquid mass delimited by its surface. This force is called surface tension. This phenomenon is what allows some insects to walk on top of the water without sinking, and it is also what gives the water droplets their shape.
On Earth, when water droplets are small enough (2 millimeters or less), surface tension overcomes gravity and they remain perfectly spherical, like morning dewdrops that form little spheres on leaves. the plants. If a drop grows much larger, it collapses under its own weight. But in space, where fluids float freely, unimpeded by gravity, even a large liquid mass is capable of assuming the most energy efficient shape possible, a perfect sphere.
Liquids can stick to surfaces thanks to a physical property called adhesion. In microgravity, if a sufficient amount of liquid is made to adhere to the inner surface of a circular ring-shaped frame, the liquid will stretch inside the frame and naturally assume a curved shape due to surface tension.
By using the proper volume of liquid, it is possible to make the surface of the liquid curve inwards instead of bulging outwards. If the liquid is reflective, that inwardly curved surface can serve as a telescope mirror.
The FLUTE project strategy involves sending liquids into space as raw material to manufacture optical components in orbit. The primary mirror would be formed within a huge circular shell and would remain in a liquid state with an extremely smooth surface to ideally collect light. In theory, FLUTE technology can be used for very large telescopes. This technology could make possible telescopes with apertures 10 times or even 100 times larger than current telescopes.
A unique feature of the liquid mirror would be its ability to repair itself if damaged in space. For example, if a micrometeorite hits the mirror surface, it would naturally repair itself in a short time.
The FLUTE team has already carried out small-scale experiments to mold optical components from liquids. He has made them in environments that emulate weightlessness, including inside an airplane in parabolic flight. He has also carried them out in real microgravity conditions, aboard the International Space Station.
The team is now working on analyzing options for key components of a fluidic telescope, further developing the mission concept, and planning a small-scale demonstration of the technology in low-Earth orbit. (Fountain: NCYT de Amazings)
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