Joint Working Group

Improvement of thermosphere models

Joint with IAG Commission 4, Sub-Commission 4.3 and ICCC

Chair: Christian Siemes (The Netherlands)
Vice-Chair: Kristin Vielberg (Germany)


Mass density, temperature, composition and winds are important state parameters of the thermosphere that affect drag and lift forces on satellites. Since these significantly influence the orbits of space objects flying at altitudes below 700 km, accurate knowledge of the state of the thermosphere is important for applications such as orbit prediction, collision avoidance, evolution of space debris, and mission lifetime predictions. Drag and lift forces can be inferred from space geodetic observations of accelerometers, which complement other positioning techniques such as GNSS, satellite laser ranging or radar tracking of space objects.


The objective of the working group is to improve thermosphere models through providing relevant space geodetic observations and increasing consistency between datasets by advancing processing methods. Broadening the observational data basis with geodetic space observations, which are available now for a time span of 20 years, will also benefit climatological studies of the thermosphere.


Planned activities:

  • Virtual group meeting in October 2020
  • Step-by-step comparison of the processing of mass density from accelerometer measurements

(last update 09.2020)