TOLEOS

Thermosphere Observations from Low-Earth Orbiting Satellites

The objective of the TOLEOS project is the production of thermosphere density and crosswind observations derived from the accelerometer measurements of the CHAMP, GRACE, and GRACE-FO missions.

The new GRACE and GRACE-FO data are now available on our FTP server (ftp://thermosphere.tudelft.nl) in the directory "version_02". We advise using an FTP client (user "anonymous", any password is accepted).

Thermosphere density observations

Altitude evolution of accelerometer-carrying satellites (top) and solar activity (bottom).

Top: Altitude evolution of accelerometer-carrying satellites launched since 2000. Colour indicates published data, while grey indicates unprocessed data. Bottom: Solar activity as indicated by the F10.7 solar radio flux index. The database spans now two solar cycles.

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Geometry

Detailed and accurate models of the satellite's geometry form the basis for the aerodynamic and radiation pressure modelling. The geometry models are published as STL files on our FTP server.

Aerodynamics

The flow of atoms and molecules around the satellite is simulated with the SPARTA DSMC code developed by Sandia National laboratories, taking into account the gas-surface interactions. The aerodynamic models are available as look-up tables on our FTP server.

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Radiation pressure

The effect of radiation pressure is modelled using ray tracing. Millions of light rays illuminate the satellite from every direction to simulate the radiation pressure, taking into account the thermo-optical properties of the surfaces.

Funded by ESA's Swarm DISC

Project team

Project lead, accelerometer, density and crosswind data processing

Density and crosswind data validation

Validation of radiation pressure modelling

Density and crosswind data validation

Address

TU Delft
Kluyverweg 1
2629 HS Delft
The Netherlands

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