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RADMON: Electronics and Logic for a Satellite Instrument


The whole Aalto-1 project is student driven. This means, that all of the actual work is done by students, with supervision from the staff of the universities and companies that are participating in the project. This also applies to the work carried out at the Embedded Computing Laboratory. The main tasks for our students are:

  • Digital system development
  • FPGA control and communication logic design
  • PCB design
  • Matlab modelling of the incoming scientific data and it's handling


A novel readout concept of the radiation monitor instrument allows a light-weight, low-power detector design with large enough dynamic range to be useful in various radiation environments from low-Earth orbits to geosynchronous orbit. The main goal of the project is to demonstrate that the proposed concept, minimizing the amount of power-consuming and slow analog amplifier electronics, is suitable for space applications. A space radiation monitor needs to measure the fluxes of ionizing corpuscular radiation present in the near-Earth space inside radiation belts and during solar particle events. The monitor, at minimum, should be able to record the spectrum of linear energy transfer (LET) of the particles hitting the detector. The radiation flux is highly variable in space and time, so the dynamic range of the instrument (in terms of its capability to measure both high and low fluxes) needs to be considerable.

At present, a typical energetic charged particle detector is a stack of semiconductor detectors, which records the ionization energy loss of the incident particles in the detector elements. The signal readout electronics typically consists of a pre-amplifier, a shaping amplifier, a peak-hold detector, an AD converter to produce a digitized signal of each particle incident on the detector, and a comparator circuit to determine when the detector is hit by a particle and to provide the timing of the amplifier chain. We propose to construct a simple radiation monitor consisting of a stack of silicon detectors and a scintillator coupled to a photodiode, that are read out using a novel concept.

RADMON will be manufactured by consortium led by University of Turku and University of Helsinki.

Aalto-1 Satellite Specifications

Aalto-1 main design specifications according to the feasibility study:

  • CubeSat based 3U design, size 30 cm x 10 cm x 10 cm, weight: 3 kg
  • Orbit: Sun-synchronous noon LEO
  • Attitude: 3-axis stabilized
  • Communication: VHF-UHF housekeeping S-band data transfer

Collaborators for Aalto-1

Main payload:

  • Imaging Spectrometer (VTT)
Secondary payloads:
  • Digital Camera (Aalto, Nokia)
  • Radiation Monitor (University of Turku, University of Helsinki)
  • Lightning detector (Nokia, Aalto)
  • Accelerometer system (Aalto)
  • Electrostatic plasma sail (Finnish Meteorological Institute)