Fraunhofer Institute for Integrated Circuits IIS
Fraunhofer Institute for Integrated Circuits IIS
Space radiation hits a satellite
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Weather Report from Space

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Space Radiation – A Danger for Satellite Missions

Space radiation is considered one of the greatest challenges for modern satellite missions. This is primarily due to our sun: it releases high-energy elementary particles through sunspots and coronal mass ejections that continuously impact satellites in Earth orbit, gradually weakening their electronic hardware and potentially causing unpredictable system failures. Therefore, protecting the spacecraft is of utmost priority. To minimize risks, developers currently rely on radiation-hardened components. However, these are specialized products that drive up the cost of satellites and limit design flexibility.

An open research question is whether regular hardware could still withstand space radiation. This could significantly reduce the costs of a satellite mission without jeopardizing its success. However, access to radiation data and a comprehensive understanding of space weather are essential.

We aim to fill this gap as part of the "EBKAS" project: we measure real-time radiation exposure in geostationary orbit and analyze the effects on the electronic components of a satellite. For this purpose, we use our Fraunhofer On-Board Processor (FOBP) – a reconfigurable payload aboard the Heinrich Hertz satellite, in which cost-effective standard memory modules are installed as radiation sensors.

The two faces of space radiation

In the FOBP, a radiation monitoring system continuously collects data on space weather and subsequently transmits it to two independent ground stations. There, it is stored for further analysis in a time series database. The effects of space radiation on the hardware in the satellite can be measured in two different ways.

Total Ionizing Dose (TID)

Since satellite missions last several years, the hardware is exposed to ionizing radiation over a long period. The exposure thus accumulates gradually. This effect is measured using the Total Ionizing Dose, which is the total energy deposited into a material by radiation. In the FOBP, this can be tracked because a UV-EPROM (Ultraviolet-Erasable Programmable Read-Only Memory) gradually loses its programmed bits due to radiation. By regularly recording the lost bits of memory, we can determine the accumulated radiation dose. The calibration for the specific dosage statement was carried out by Fraunhofer INT.

 

 

Single Event Upsets (SEU)

In space, individual high-energy particles such as protons or heavy ions can hit semiconductor devices of the satellite. Such Single Event Upsets show their effects immediately, in contrast to TID: they trigger radiation-induced errors that alter the state of a bit in memory or in logic circuits. To detect such bit flips in the FOBP in real-time, a commercial SRAM (Static Random-Access Memory) module is used. If there are sudden deviations in the patterns of the memory, we can trace the radiation exposure at a specific time.

What comes next

The "EBKAS" project is in full swing: the radiation monitoring system has already collected the first data from space. Both radiation effects could be demonstrated: the SRAM module was able to measure bit flips and thus detect Single Event Upsets in real-time, while the gradual bit loss in the UV-EPROM aligns with the expected effects of the Total Ionizing Dose. Since the Heinrich Hertz satellite is expected to operate for over a decade, we can now analyze larger data sets over a longer period using the FOBP to better understand the long-term consequences of space radiation for satellite missions. Specifically, we want to:

  • Compare radiation patterns at different times and conditions of space weather
  • Validate the applicability of standard memory modules as a cost-effective alternative to radiation-resistant hardware
  • Gain insights into the design of satellites for future missions

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