Imagine a space telescope with a mirror 50 meters wide—larger than a soccer field and nearly eight times the diameter of the James Webb Space Telescope (JWST). This ambitious vision is at the heart of the FLUTE (Fluidic Telescope) project, a joint initiative by NASA and Technion. Unlike traditional telescopes made of precisely manufactured glass, FLUTE proposes a revolutionary mirror made from liquid, suspended and shaped by surface tension in the microgravity of space. This concept may redefine what is technologically possible in space-based astronomy.
Building larger space telescopes has long faced severe constraints. Even JWST, with its 6.5-meter segmented mirror, pushed the boundaries of what current rockets could deploy. Scaling up to tens of meters—needed to directly image Earth-like exoplanets—is effectively impossible with conventional materials and folding mechanisms. FLUTE addresses this bottleneck by leveraging the unique behavior of liquids in space. In zero gravity, a liquid film naturally forms a perfect spherical surface, ideal for collecting and focusing light. This eliminates the need for rigid, heavy, and complex mechanical systems used in current mirror designs.
However, one of the major challenges is how such a liquid mirror would respond when the telescope slews—moves—from one target to another. To address this, Israel Gabay and his colleagues at Technion developed a theoretical model to predict how a thin liquid mirror reacts to angular acceleration. Their mathematical framework uses advanced analytical techniques to show how the liquid surface deforms during and after such movements.
Their findings revealed both promise and limitations. When a 50-meter liquid mirror, just 1 millimeter thick, undergoes standard slewing maneuvers, surface disturbances can reach several micrometers at the edges. However, these deformations move inward very slowly—taking years to reach the center of the mirror. Critically, the central 80% of the mirror remains within optical tolerance, even after a decade of daily maneuvers. This demonstrates that most of the mirror can remain effective for high-resolution imaging over long periods.
A new operational concept was introduced: the “manoeuvring budget.” This budget would track the amount and type of telescope movements over time to avoid exceeding the threshold at which optical performance degrades. Interestingly, the study also showed that multiple smaller movements in different directions can produce more symmetrical deformations, which are easier to correct than the effects of one large shift.
To validate their models, the researchers carried out lab experiments with microscopic liquid films, manipulating them using contactless electromagnetic forces. Despite the massive difference in scale, the experimental data aligned with their predictions, confirming the model’s accuracy.
Beyond enabling massive mirrors, FLUTE opens new possibilities for adaptive space optics. Liquid mirrors could reshape for different tasks, self-correct distortions, or even recover from micrometeorite damage. With the potential for periodic “resets” to restore mirror quality, such telescopes could operate for decades.
Ultimately, FLUTE represents a fundamental shift—from precision hardware engineering to mastering fluid behavior in microgravity. As space agencies plan next-generation observatories, this fluidic approach could be key to unlocking the next frontier in astronomical discovery.