Internship title: Impact of variable area modelling for drag on propagation accuracy for LEO satellites

Currently, most operators, including EUMETSAT, are considering a fix average frontal area of the spacecraft as input into their atmospheric drag model, when generating predicted ephemerides. That approximation is normally more than sufficient to ensure correct maintenance of the spacecraft within its operational orbital limits; however, that’s not necessarily the case for Space Traffic Management operations, as any inaccuracy in orbital estimation may result into an inaccurate evaluation of a conjunction risk. It is therefore recommended to improve as much as possible the accuracy of the predicted ephemerides used for these operations by considering an accurate variable value of the frontal area of the spacecraft as input into the atmospheric drag model.

The main goal of this internship would therefore be to implement a prototype of this variable area model into a reference propagator, in order to evaluate the benefit of this model in terms of accuracy of the predicted orbit versus the consolidated estimated orbit; the accuracy provided by the currently used fixed area model would be used as benchmark value.

If the observed benefit is important, a second step would be to implement platform dependent models to compute the variable area profile from the predicted attitude of the satellite and the orientation of the movable parts (e.g. the solar array). This improvement is expected to be particularly beneficial for missions with large movable parts, such as Metop Second Generation, with large attitude changes, such as CO2M and flying at very low altitude, such as Sterna.

• Familiarization with the SW modules available in EUMETSAT for LEO satellite orbit propagation.
• Selection of most suitable orbit propagation SW module for prototyping of a variable drag area model (i.e. drag area evaluated as function of the time of the propagation).
• Analysis of propagation accuracy using the new variable drag area model versus the result provided by the equivalent fixed drag area model.

• If improvements observed, development of mission specific modules for generation of the variable drag area model from the models describing the platform attitude and the displacement of the movable parts (e.g. solar array) for the most interesting missions (CO2M, Metop Second Generation, Sterna).
• Document and synthesize results accordingly in a document report and an end-of-internship presentation

• Have the ability to work effectively in English;
• Be computer literate;
• Be intrinsically motivated and curious about the internship subject;
• Be able to work independently and collaboratively;
• Have the ability to take the initiative in researching ideas;
• Have the ability to collect, collate, conceptualize and present information clearly.

Additional advantageous requirements:

• Knowledge in orbit mechanics;
• Familiarity with Linux systems and with Python would be desired.