Artist's impression of the CHaracterising ExOPlanet Satellite (CHEOPS) – Front View.


Mission Overview

The first ESA-S class mission CHEOPS (CHaracterising ExOPlanet Satellite) was launched in 2019 to provide ultra-high precision photometry measurements of transits of known exo-planets. It carries only a single optical instrument, which is equipped with a data processing unit that runs the instrument flight software (IFSW) to carry out various ECSS-Service oriented control and highly tailored data processing tasks.

Contribution of our Team

The IFSW software was developed at the University of Vienna as an open-source software, which includes all drivers and modules the flight software is composed of, but also the EGSE (Electronic Ground Support Equipment) software and the simulators used for the development.

The Data Processing Unit (DPU) hardware of CHEOPS is built by the Institute for Space Research, IWF Graz. As processor, the GR712RC dual-core Leon3 was chosen, mainly because it already includes a Milbus (MIL-STD-1553) core, which is needed for the communication with the spacecraft (AS-250 platform). Internally, SpaceWire is used to communicate with the camera detector unit. The DPU is equipped with 64 MiB SRAM and a 16 GB FLASH memory. The two cores are used in Asymmetric Multi-Processing (AMP) style, but only a single shared executable is run. When looking hierarchically at the IFSW, it is composed of three layers, a basic software, an ECSS services-providing framework and the high level application software.

On the highest level of the application are the science data processing tasks. The main task of the IFSW is to process the optical CCD images of the detector unit and compress them in real-time. This task is achieved by a highly tailored, yet configurable data processing chain. Another interesting task of the application software is the provision of precise position measurements to the spacecraft in a closed loop and target recognition algorithms to enable the identification of the correct star and to move it to the desired location on the CCD.

Involved Personnel

Science Lead: M. Güdel

Project Lead: F. Kerschbaum

Technical Lead: R. Ottensamer

Development Team: A. Luntzer, R. Ferstl, P. Löschl, C. Reimers, M. Mecina

Next important Milestones

The flight software has been qualified and delivered to the Swiss mission project lead. It was successfully installed on the flight model afterwards.

CHEOPS was launched on 18 December 2019.


The IFSW development is funded by the ESA PRODEX programme under project number C4000112123.

Links & Downloads

CHEOPS mission homepage

CHEOPS git (CHEOPS Instrument Application Software)


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