Kyoto University scientists map thermospheric density using 1,200 Starlink satellites
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Researchers at Kyoto University use orbital data from about 1,200 Starlink satellites to produce the first two-dimensional map of thermospheric density. The map, at roughly 500 kilometers altitude, shows density patterns consistent with observations from the European Space Agency's SWARM satellites. The work builds on an earlier Starlink-based study that tracked density changes over time and altitude.
Key Facts
- Kyoto University researchers produced a two-dimensional latitude-longitude map of thermospheric density at roughly 500 kilometers altitude.
- The team estimated thermospheric density around approximately 1,200 Starlink satellites flying at 482 kilometers altitude.
- The resulting density patterns showed consistency with observations from the European Space Agency's SWARM satellites.
- The new analysis expands on an earlier study that used Starlink Two-Line Element data to estimate how thermospheric density changed over time and altitude.
Thermospheric Density
The thermosphere is the neutral gas region between 100 and 1000 kilometers above Earth and accounts for more than 99 percent of the upper atmosphere. At several hundred kilometers, residual atmospheric drag still slows satellites, making density measurements important for orbit forecasting and collision avoidance. The ionosphere, by contrast, is ionized gas that makes up less than 1 percent of the atmosphere and is easier to observe because it affects radio wave propagation.
Starlink Tomography Method
Kyoto University researchers used publicly available Starlink orbital information and applied tomography, a method common in medical imaging, to map upper-atmosphere drag. By tracking the gradual decay of satellite orbits, the team estimated thermospheric density around approximately 1,200 satellites flying at 482 kilometers altitude. The resulting snapshot forms a two-dimensional latitude-longitude map at roughly 500 kilometers altitude. The analysis builds on an earlier study that used Starlink Two-Line Element data to estimate how density changed over time and altitude.
SWARM Validation
The latitude-longitude snapshot produced at roughly 500 kilometers altitude showed consistency with density changes measured by the European Space Agency's SWARM satellites. The team describes the result as the first tomographic analysis of thermospheric density of its kind. Corresponding author Mamoru Yamamoto says the study bridges space science and space engineering and emerged from reading papers in both research fields.
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Kyoto University scientists map thermospheric density using 1,200 Starlink satellites
