• Downlink Frequency: 435.780 MHz (UHF)
  • Downlink Modulation: BPSK
  • Downlink Baud Rate: 9600 bps

1. Intro

SIGMA(Scientific cubesat with Instruments for Global magnetic field and rAdiation) : KHUSAT-03

Kyung Hee University (KHU) has been developing a CubeSat for the space science mission called Scientific cubesat with Instrument for Global Magnetic field and rAdiation (SIGMA), which installed Tissue Equivalent Proportional Counter (TEPC) and a magnetometer. SIGMA has a 3U CubeSat, and the weight is about 2.9 kg. The primary payload, TEPC, measure the Linear Energy Transfer (LET) spectrum and calculate the equivalent dose for the complicated radiation field in the space. The secondary payload, magnetometer, measures the global magnetic fields. It has 0.1 nT resolution in the dynamic range of ±52000 nT.

The FM KHUSAT-03 of SIGMA mission

For a space exploration, there is a concern about cosmic radiation exposure while astronauts are carrying out various missions, and many efforts have been made to secure the safety of the astronauts. The Scientific cubesat with Instrument for Global Magnetic field and rAdiation (SIGMA) has a Tissue Equivalent Proportional Counter (TEPC) as the main payload which can measure the Linear Energy Transfer (LET) spectrum and equivalent dose for complicated radiation filed in the space environment. The SIGMA also has a miniaturized fluxgate magnetometer as the second payload.

We expected that the orbit altitude is approximately 750 km sun-synchronous orbit, and the inclination is 98 degrees. If we can measure the total dose and LET in interesting altitude through the CubeSat, it will be helpful for a space science research.

Project Organization

– Satellite System/Operation: SSR/KHU(School of Space Research, Kyung Hee University),
– TEPC: KASI(Korea Astronomy and Space Science Institute),
– Magnetometer: NJIT(New Jersey Institute of Technology), UNH(University of New Hampshire),
– Attitude Control: YU(York University),


-MSIP(Ministry of Science, ICT and Future Planing), KARI(Korea Aerospace Research Institute)

2. Payloads


A detector should be used directly to evaluate the equivalent dose. The material for the detector must be the tissue equivalent material. The tissue equivalent material, A-150, is used for the TEPC wall, and the tissue-equivalent gas consists of C3H8 (55%)+CO2 (39.6%)+N2 (5.5%) for internal detection gas. Main scientific payload, TEPC, measures the LET spectrum and calculate equivalent dose in the space. TEPC can measure from 0.2 to 300 keV/μm with a single Multi-Channel Analyzer (MCA) measurement range.


Figure 1: Development of the TEPC: (a) Design of the TEPC assembly, (b) Structural detail design of the TEPC sensor, (c)  The TEPC test and gas injection.

Figure 1a is the concept design of the TEPC. Three small Printed Circuit Board (PCB) are shown high-voltage distribution board, pre-amplifier board and signal connector for the spherical detector. And two big PCBs are shown DC-DC converter board and interface board. TEPC is supplied the voltage from the Instrument Interface Board (IIB).



Secondary payload, a Miniature fluxgate magnetometer, expects to have around 1 nT resolution in the dynamic range of ±54000 nT. Miniature fluxgate magnetometer is compact and light weight design for CubeSat with low noise and high sensitivity performance appropriate for wave observations rather than magnetic sensors like Magneto Resistive (MR) type used CubeSat missions before. This magnetometer is developing present in New Jersey Institute of Technology(prof. Marc R. Lessard and H. M. Kim) and University of New Hampshire.

33 22