Speakers
Description
Mission
NORM is the Norwegian Radiation Monitor for measuring energetic charged particle radiation in space. NORM is designed as an easily adaptable space radiation monitor for satellite missions in GEO, LEO, and HEO. The development is funded by ESA.
NORM’s first flight will be on the Arctic Satellite Broadband Mission (ASBM) in a highly-elliptical three point apogee orbit (HEO-TAP). The ASBM mission lifetime is 15 years, NORM will be operated for at least 5 years.
Since the ASBM’s HEO orbit is unique and traverses different radiation environment domains, the prediction of the radiation environment for this mission comes with some uncertainty. That is why NORM will be useful to validate existing and new radiation environment models by its data taking aboard the ASBM spacecraft.
Particle Detection
NORM allows to measure the rate and kinetic energy of electrons (0.5 – 7 MeV) and protons (7 – 200 MeV) in space. The resulting coarse differential flux spectra for electrons and protons allows for rough dosimetry, characterisation of the radiation environment and its variation over time.
System Design
The NORM instrument is made up of two main physical units, the Data Handling Unit (DHU) and the Data Gathering Unit (DGU). The DGU contains the radiation detector and integrated readout electronics utilising the IDEAS IDE3466 readout ASIC. The radiation detector is a particle telescope made of 9 silicon diodes and aluminium/tantalum absorbers shielded in a cylindrical vault. The diodes generate an electrical charge when they are exposed to charged particles. The trigger pattern of the diode stack is evaluated in the IDE3466 ASIC to classify the particle types and kinetic energy. In addition, the condition for coincidence trigger patterns suppresses background from particles outside the intended field-of-view. A dual-layered radiation shielding further reduces undesired background radiation.
To compensate for detectors optimised for each type of radiation NORM will take full advantage of the programmable thresholds and patterns being able to quickly reconfigure the instrument, in-flight calibration and attention to instrument noise considerations from an early stage that is critical for electron and high-energy proton detection capability.
The DHU hosts the data processing and power supply. We use the new Microchip SAMRH71 ARM microcontroller for interfacing with the IDEAS IDE3466 ASIC and for receiving commands and transmitting telemetry over the satellites MIL-STD-1553B bus. The SAMRH71 also provides a CAN and a SpaceWire bus, opening up the possibility of using NORM on other satellites as well. No FPGA is used.
Status
By the time of SPACEMON 2020 NORM the engineering model will be available with on-going testing. Qualification is scheduled for the first half of 2021 and we hope to deliver the flight unit in the summer of 2021, which is arguably an ambitious schedule, especially in the times of the Corona pandemic. The launch of the ASBM satellites is planned for late 2022.
