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Proba-2 TPMU

Development of thermal plasma measurement unit for ESA Proba-2 satellite

Czech device onboard Proba-2 satellite

Project duration: 2005 to 2008

Project manager: František Hruška

The Thermal Plasma Measurement Unit (TPMU) device was designed and developed at the Institute of Atmospheric Physics ASCR and the flight model manufactured in cooperation with the Czech Space Research Centre (CSRC) in Brno. The project was designed to obtain new scientific data to research the behavior of thermal plasmas in the vicinity of Earth. The second objective is to verify the new design of the electronics and its behavior in space environment, as the basis for the use of the device in future satellite projects.

TPMU device is placed in a box made of aluminum alloys containing the electronics block and block of measuring sensors with the retarding potential analyzer and radio-frequency sensors. The entire box is mounted on the upper side of the DSLP control unit that provides both power and data processing for TPMU. The ion measurement is based on the retarding potential analyzer and uses planar sensor, which contains a set of internal electrodes. The electrodes are gradually fed by increasing positive voltage, which controls flow of ions from the surrounding plasma. On collecting electrode is then given only ions with certain energies. The dependence of current on voltage gives data for calculation of the total ion concentration, temperature and approximate composition. It can distinguish ions of oxygen, hydrogen and helium. To obtain the electron temperature there is a sensor with electrodes, which are fed with pulses of radio frequency signals around 50 kHz. Signal amplitude is regulated so that the output voltage is maintained at a constant level. The magnitude of this amplitude is determined as the value for electron temperature calculation.

Data obtained from the device will be used to study processes in thermal plasma and after accumulation of sufficient data also for the construction and improvement of empirical models, especially the construction of a new global model at the height of the satellite orbital path.

Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic

The Institute is focused on the research of physical processes in the Earth’s atmosphere and in interplanetary space. The broad field is covered by five scientific departments including the Space Physics Department to which the described project belongs.

What would you name as main benefits of the project to you and your institute?

“It was the first opportunity for us to participate in the ESA project as supplier of equipment. It was also an opportunity to learn to work according to rules and standards of ESA and the chance to visit a top workplace in ESTEC and Verhaert. This experience is now exploited for our participation in other space projects.”