Researchers at Kyoto University in Japan have turned SpaceX’s satellite internet constellation into an atmospheric instrument. Using publicly available orbital information from about 1,200 Starlink satellites, the team produced what it calls the first tomographic map of the thermosphere — a layer of Earth’s upper atmosphere that scientists have long struggled to measure directly. The work was written up by Science Daily on 11 August 2026 from materials provided by Kyoto University, reported a day earlier by Indian outlet Mid Day, and picked up on 17 August by the engineering site Hackaday.
By the numbers
- ~1,200 — Starlink satellites whose orbital decay was analysed.
- 482 km — the altitude at which those satellites fly.
- More than 99% — the share of the upper atmosphere that is electrically neutral gas, i.e. the thermosphere; the ionised gas of the ionosphere accounts for less than 1%.
- 100–1,000 km — the altitude band that thermospheric density covers.
- 2021 — the year SpaceX began publishing near-real-time ephemeris data for individual Starlink satellites, per Hackaday.
Figures from Science Daily unless otherwise noted.
What the team actually did
The method starts with something every low-orbit operator already tracks: satellites sink. Science Daily explains that the team read atmospheric drag out of the gradual decay of the Starlink satellites’ orbits, then used that to estimate the density of the air around roughly 1,200 spacecraft flying at 482 kilometres. Feeding those many separate readings into a tomographic reconstruction — a technique the outlet notes is more familiar from medical imaging — produced a two-dimensional latitude-longitude snapshot of thermospheric density. The researchers describe it as the first tomographic analysis of its kind.
The result was not taken on trust. The density patterns showed strong consistency with observations from the European Space Agency’s SWARM satellites, which measure density changes along their own orbital paths. Mamoru Yamamoto of Kyoto University is the corresponding author.
Why the thermosphere is so hard to see
More than 99 percent of the upper atmosphere is electrically neutral gas known as the thermosphere, according to Science Daily, and thermospheric density refers to the density of that neutral atmosphere between roughly 100 and 1,000 kilometres above the surface. The ionised gas of the ionosphere makes up less than 1 percent of the atmosphere by comparison.
That small ionised fraction happens to be the easy part. Because ionised gas affects the way radio waves travel, the report says, the ionosphere is relatively straightforward to observe from the ground. The neutral gas that makes up almost all of the layer leaves no such radio fingerprint, which is why conditions in the thermosphere have remained far harder to measure — and why a fleet of satellites quietly losing altitude inside it turns out to be so useful.
What it means for satellite internet
Science Daily frames the stakes in terms of traffic. The region around Earth is getting more crowded as thousands of satellites and pieces of debris move through low Earth orbit, and even at altitudes of several hundred kilometres the traces of atmosphere that remain still exert enough drag to slow satellites down. Measuring that density accurately therefore feeds directly into forecasting satellite motion and reducing collision risk — both between satellites, and between satellites and debris.
For readers who buy satellite internet rather than fly it, the connection is indirect but real. Drag is the force that pulls low-orbit broadband satellites back toward Earth, and better density data is what tells operators where a spacecraft will actually be tomorrow. That is the same arithmetic behind what a constellation of this size means for debris rules: the bigger the constellation, the more conjunction warnings and avoidance manoeuvres depend on knowing the density of the air it is flying through. Worth stating plainly, though: none of the three reports links the research to Starlink pricing, subscription plans or country availability, and none of them claims any change to the service customers receive.
How the Starlink data is used
Hackaday supplies the engineering view. SpaceX has published near-real-time ephemeris data for individual Starlink satellites since 2021, and from that stream researchers can deduce atmospheric density at specific altitudes and times — information the site says would otherwise be very hard to gather. It calls the resulting archive an invaluable dataset for studying the outermost part of the atmosphere.
From TLEs to tomography
The novelty in Yamamoto’s paper, as Hackaday reads it, is the shift away from the usual two-line element (TLE) set toward a tomographic approach that uses far more data to build a larger reconstruction, with resolution claimed to be about on par with the SWARM satellites. Its summary is blunt: although these spacecraft were never designed to be more than data relays, they may have accidentally become the biggest development in thermospheric research in a long time.
Building on earlier work
This is the team’s second pass at the problem. Science Daily says the new analysis expands on an earlier study by the same group, which used Starlink TLE data to estimate how thermospheric density changed over time and altitude. The new work adds a dimension by examining how density varies horizontally across latitude and longitude, revealing more of the thermosphere’s geographic structure.
An independent cross-check
Hackaday points to separate work as well: a 2025 paper by Zhuoliang Ou and colleagues, published in the journal Remote Sensing, which drew on the same Starlink data source to investigate the thermosphere. That team, per Hackaday, established that the Starlink data matches well with data from a dedicated research satellite, SWARM-B, making it a genuinely useful scientific source rather than a convenient proxy.
Yamamoto framed the project as a bridge between two communities. “This is a multidisciplinary study between space science and space engineering,” he said in comments carried by Science Daily, adding that reading papers from both fields convinced the team that deeper dialogue between the two was necessary.
One discrepancy in the reports
The coverage does not fully agree on altitude. Science Daily says density was estimated around satellites flying at 482 kilometres and that the resulting snapshot maps density at an altitude of roughly 500 kilometres. Mid Day reports that the analysis revealed atmospheric density patterns roughly 482 kilometres above Earth, without citing the 500-kilometre figure.
What comes next
The technique could eventually support near-real-time measurement of atmospheric density around satellites, Science Daily says, and that kind of continuous monitoring could improve space weather forecasting while contributing to safer, more dependable satellite operations. The outlet’s closing point is that the practical benefits only grow as the number of objects orbiting Earth continues to increase.
One gap is worth flagging for anyone following SpaceX’s hardware roadmap: none of the three reports connects the research to the company’s own plans, and none mentions the next-generation Starlink V3 satellites or how a larger, heavier generation of spacecraft might interact with the drag environment the Kyoto team has now mapped.
Frequently Asked Questions
Which other spacecraft sit inside the thermosphere?
According to Hackaday, the thermosphere contains Starlink satellites as well as both currently active space stations, the International Space Station and China’s Tiangong. Hackaday says the layer starts just before the 100km altitude that is generally recognised as the boundary of space.
How long has Starlink been publishing the orbital data used in the study?
Hackaday reports that SpaceX has published this data since 2021, describing it as near-real-time ephemeris data on individual Starlink satellites. Hackaday calls the resulting archive an invaluable dataset for studying the outermost part of the atmosphere.
What is tomography, and why apply it to the atmosphere?
Tomography builds a cross-sectional picture of something by combining many separate measurements taken from different angles, and Science Daily notes the technique is more commonly associated with medical imaging. Hackaday explains that the innovation in the Kyoto paper is moving away from the usual two-line element (TLE) set to a tomographic approach that uses more data for a larger reconstruction, with the resolution claimed to be roughly on par with the European Space Agency’s SWARM satellites.
Where does the thermosphere end?
Hackaday says the thermosphere sits below the exosphere and that its thickness fluctuates with factors such as solar irradiation, which also shifts the exact altitude at which the exosphere begins. Hackaday states that boundary is generally well above 600km.
Who led the research?
Science Daily names Mamoru Yamamoto of Kyoto University as the corresponding author, and says the write-up was produced from materials provided by Kyoto University. Yamamoto told Science Daily the work was a multidisciplinary study between space science and space engineering.
Does the research change Starlink prices or service?
The sources describe scientific and space-engineering benefits only. Science Daily lists better forecasting of satellite motion, reduced collision risk and possible improvements to space weather forecasting; none of the three reports mentions any change to Starlink pricing, plans or country availability.
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