Speaker
Description
For the design and operation of spacecraft in orbit it is necessary to measure and monitor the complex radiation field in outer space [1]. Also, for the assessment of radiation effects on instruments and electronic components which can be sensitive to radiation degradation and single event effects [2]. Space radiation in low-earth-orbit (LEO) contains a wide variety of particles, from energetic protons, light ions and electrons from the Earth’s radiation belts and from the Sun – in particular solar particle events and induced geomagnetic storms. Such particles exhibit a large spectrum of energy from the keV level up to tens of MeV for electrons and hundreds of MeV for protons while they interact with spacecraft in free space from all directions with high temporal, spatial and directional variability along the spacecraft orbit. Moreover, the radiation field is further modified by interactions of the primary particles in the satellite bulk material and the production of secondary radiation. Detecting and characterizing such a complex field of highly dynamic and broad distributions of varying particles and wide energy is desired in essentially all satellites ideally with a single, compact and low-power instrument. This task is achieved with the MiniPIX-Timepix3 Space radiation monitor (Fig. 1a) which has been deployed in open space onboard OneWeb’s JoeySat satellite (Fig. 1b) launched to LEO orbit in May 2023. The detector settings, operation uptime and duty factor were customized to the satellite resources and available data rate. Raw data is retrieved and processed in high resolution on ground. The Timepix3 ASIC chip provides the composition of the mixed-radiation fields (field decomposition into particle-type classes) with detailed dose rates and particle fluxes (total and partial) [3]. Deposited energy spectra and liner-energy-transfer (LET) spectra are measured in wide range with high selectivity for protons, ions and electrons – see Fig. 2. Together with the spacecraft navigation stamp, results and physics products can be also provided as detailed spatial location maps and time distributions along the satellite orbit [4].
References
[1] A. Vampola, et al., IEEE Trans. Plasma Sci. 28 (2000) 1831–1839
[2] R. Ecoffet, R., IEEE Trans. Nucl. Sci. 60 (2013) 1791–1815
[3] C. Granja, et al., IEEE Trans. Nucl. Sci. 71 (2024) 921-931
[4] C. Granja C., et al., Planetary and Space Science 125 (2016) 114-129
