For years, physicists treated an Earth-to-space quantum uplink as a beautiful idea that nature simply would not allow. Now a set of detailed models and experiments suggests that the same fragile quantum light once thought doomed by turbulence and loss could, in fact, survive the trip from the ground to orbit, opening a realistic path to global quantum networks.
The shift is not just a technical tweak, it is a reversal of what many researchers assumed was fundamentally impossible, and it arrives at a moment when governments and companies are racing to secure communications against future quantum computers. If the new work holds up in practice, the most challenging leg of a quantum internet, beaming entangled light from Earth to satellites, may move from science fiction to engineering problem.
Why an uplink looked impossible in the first place
When researchers first mapped out quantum communication via satellites, they quickly converged on a simple rule of thumb: send the delicate quantum states from space down to Earth, not the other way around. The logic was brutal but compelling, since it is easier to hit large, fixed telescopes on the ground than to track a small, fast moving satellite and because atmospheric turbulence near the surface was expected to shred any quantum signal on the way up, a view captured in early discussions that treated an uplink as effectively impossible. That intuition hardened into a design dogma for quantum networks that relied on satellites as trusted relays.
In that picture, the atmosphere acts like a noisy, shifting lens that scatters and distorts single photons, the individual particles of light that carry quantum information. The lower layers of air are especially turbulent, so sending quantum light up through them was seen as a recipe for losing the very properties that make it useful, such as entanglement and precise polarization. As a result, most early space experiments focused on downlinks, where a satellite beams quantum states through the thinner, calmer upper atmosphere to ground stations, and uplinks were often dismissed in passing as too lossy or unstable to be worth serious modeling.
The new modeling that flips the script
The latest work challenges that pessimism by treating the atmosphere not as an impenetrable barrier but as a complex optical channel that can be modeled and, to some extent, engineered around. In detailed simulations described as Scientists prove “impossible” Earth to space quantum link, researchers show that quantum signals can be shaped and timed so they survive the worst of the turbulence on their way from the ground to orbit. Instead of assuming that every fluctuation in air density destroys the signal, the models track how single photons propagate through realistic layers of moving air and identify windows where loss and distortion stay within tolerable bounds for quantum communication.
Crucially, the team does not rely on exotic hardware that only a handful of labs could build. The same analysis that underpins the Modeling the “Impossible” Scenario suggests that with carefully chosen wavelengths, adaptive optics, and realistic telescope sizes, an uplink can deliver enough entangled photons to be useful. By treating the problem as a full end to end system, from photon source on the ground to detector in orbit, the researchers show that the supposed impossibility was more a reflection of incomplete modeling than a hard law of physics.
How the Earth-to-space quantum link actually works
At the heart of the new scenario is a simple but demanding idea: fire two single particles of light from separate ground stations so that they meet and interfere in a satellite based receiver. In the scheme described in the Researchers have shown that quantum signals can be sent from Earth up to satellites, each ground station prepares quantum light in a specific state, sends it through the atmosphere, and relies on the satellite to perform a joint measurement that effectively entangles distant users. The satellite does not need to store quantum information for long periods, it simply acts as a fast, precise referee that tells the ground stations which pairs of photons ended up correlated.
This approach turns some of the old disadvantages of an uplink into manageable engineering constraints. Because the satellite only needs to detect and compare incoming photons, it can be relatively compact and power efficient, while the heavy, complex sources of entangled light stay on the ground where they are easier to maintain and upgrade. The modeling shows that even after accounting for atmospheric loss, pointing errors, and detector inefficiencies, the rate of successful quantum events can be high enough to support secure key distribution between distant points on Earth, provided the system is tuned to the right operating regime.
From downlink milestones to a full quantum network
The new uplink work builds on a decade of progress in sending quantum states from orbit down to Earth, which proved that space based links can outperform fiber over long distances. One landmark experiment teleported photons over roughly 300 miles using a satellite, with the advantage that the particles of light traveled through space for much of their journey, avoiding the absorption and scattering that plague glass fibers, a result captured in reports that teleport photons 300 miles into space. Those downlinks showed that quantum states can survive the trip through the upper atmosphere and that satellites can serve as practical nodes in a quantum network.
What was missing was a way to close the loop so that ground stations could also send quantum information up, enabling more flexible architectures where satellites connect multiple users rather than just broadcasting down. Earlier theoretical work had already hinted that a global quantum internet was possible in principle, with one study arguing that global quantum communication is going to be possible if losses and noise can be managed. The new uplink modeling fills in a crucial piece of that puzzle by showing that the hardest leg of the journey, from Earth to space, can be engineered to meet those requirements.
Why researchers misjudged the uplink for so long
The gap between earlier pessimism and the new optimism reflects how quickly both quantum technology and atmospheric modeling have evolved. When scientists first weighed the idea of an uplink, they were working with less efficient photon sources, noisier detectors, and cruder models of turbulence, so it was reasonable to conclude that the signal would be swamped. As one analysis of the field notes, Plus, it’s easier to hit larger, more fixed targets on the ground than a roving satellite in space, which nudged designers toward downlinks and away from more ambitious two way schemes.
That early bias shaped funding, experiments, and even the language researchers used, with some reviews flatly stating that an uplink was not viable. Over time, however, improved adaptive optics, better control of photon sources, and more accurate atmospheric data made it possible to revisit the question with fresh tools. As more groups began to explore the limits of satellite based quantum communication, the old assumption that an uplink was off the table started to look less like a law of nature and more like a snapshot of what was practical at the time.
Evidence that quantum light can survive the trip up
The strongest support for the new models comes from experiments that show quantum light can be beamed upward through the atmosphere without losing its essential properties. In work highlighted under the banner Thought to Be Impossible: Scientists Show Quantum Light Could Be Beamed Up, By University of Technology Sydney researchers demonstrate that carefully prepared quantum states can be sent toward space and still be detected with high fidelity. The experiments use realistic atmospheric paths and hardware that could be adapted for satellite links, rather than idealized lab setups, which strengthens the case that the uplink is not just a theoretical curiosity.
These results dovetail with broader reporting that Scientists Thought a Quantum Satellite Uplink Was Impossible Until Now, underscoring how quickly the field has moved from skepticism to demonstration. By showing that entangled or otherwise non classical light can traverse the same turbulent layers that once seemed fatal, the experiments provide a concrete benchmark for what future satellite receivers must handle. They also validate key assumptions in the new models, such as how beam divergence and turbulence interact, giving engineers confidence that the predicted performance is within reach of existing or near term technology.
What a global quantum internet could look like
If Earth to space links become routine, the architecture of a quantum internet starts to look far more flexible and scalable than fiber alone would allow. Satellites in low Earth orbit could act as switching points that connect cities on different continents, while higher orbit platforms provide more stable but slower links, all tied together by ground stations that share entangled photons and secret keys. Earlier theoretical work that argued a global quantum internet really is possible assumed that some combination of satellites, fibers, and quantum repeaters would eventually close the gaps; the new uplink results make that vision more concrete by showing how the most challenging connections might be built.
In practical terms, such a network would not replace the classical internet but sit alongside it, providing ultra secure channels for tasks like diplomatic communications, financial transactions, and critical infrastructure control. Quantum key distribution, where users share encryption keys guaranteed by the laws of physics rather than computational hardness, is the most immediate application, but distributed sensing and clock synchronization could follow. With satellites able to both send and receive quantum states, operators could route entanglement where it is needed, stitch together regional networks, and dynamically reconfigure paths in response to demand or outages.
Engineering challenges that still stand in the way
None of this means the engineering is trivial. Pointing a narrow beam of single photons from a ground station to a fast moving satellite requires exquisite tracking and stabilization, and the system must do it while compensating for turbulence that changes on millisecond timescales. The models that underpin the Scientists prove “impossible” Earth to space quantum link work assume high quality optics, low noise detectors, and precise timing, all of which must be ruggedized for real world conditions. Weather, cloud cover, and even air traffic can interrupt links, so operators will need constellations of satellites and multiple ground stations to maintain continuous coverage.
There is also the question of cost and standardization. Building a global network of quantum capable satellites and ground terminals will require coordination between space agencies, telecom operators, and national security bodies, each with their own priorities and constraints. While the physics now looks favorable, the path from demonstration to deployment will hinge on whether these stakeholders see enough value in quantum security and sensing to justify the investment, and whether they can agree on common protocols so that different systems interoperate rather than forming isolated islands.
Why this matters beyond physics labs
The stakes extend far beyond the satisfaction of proving that an “impossible” link is actually feasible. As quantum computers advance, they threaten to break widely used encryption schemes, raising the risk that data intercepted today could be decrypted in the future. A functioning Earth to space quantum network would give governments and companies a way to distribute keys that even a powerful quantum computer cannot compromise, because any attempt to eavesdrop on the quantum channel would leave a detectable trace. That is why reports emphasize that Scientists have proven that quantum signals can be sent from Earth to satellites in ways that may enable the development of a global quantum internet.
There are also scientific and economic dividends. A network of entangled links spanning the planet could support new kinds of experiments in fundamental physics, such as tests of quantum mechanics over unprecedented distances or precision measurements of gravitational effects on entangled states. On the commercial side, companies that master the hardware and protocols for satellite based quantum communication could find themselves supplying critical infrastructure to banks, cloud providers, and defense contractors. In that sense, the shift from “impossible” to “doable” is not just a technical milestone but a signal that a new layer of the information economy is starting to take shape.
From “thought to be impossible” to the next set of questions
The narrative arc here is striking. Not long ago, the idea of sending fragile quantum light from Earth to orbit was filed under Thought to Be Impossible, and experts routinely advised focusing on downlinks or fiber based solutions instead. Now, detailed modeling, targeted experiments, and a better understanding of atmospheric channels have converged on a different conclusion: with the right design choices, an uplink is not only allowed by physics but potentially competitive with other approaches. That reversal is a reminder that in fast moving fields like quantum communication, yesterday’s impossibilities can become tomorrow’s design constraints.
The next phase will be less about proving that an uplink can work at all and more about optimizing and integrating it into broader networks. Researchers will need to refine protocols that account for variable link quality, develop error correction schemes tailored to satellite channels, and explore hybrid architectures that combine quantum and classical resources. As those efforts unfold, the once “impossible” Earth to space quantum link is likely to be judged not by whether it can be done, but by how reliably, cheaply, and widely it can be deployed.
More from MorningOverview