CubeSat Observation of the Radiation Field of the South Atlantic Anomaly

Pavel Kovář,Marek Sommer

doi:10.3390/rs13071274

Abstract

The movement of the South Atlantic Anomaly has been observed since the end of the last century by many spacecrafts equipped with various types of radiation detectors. All satellites that have observed the drift of the South Atlantic Anomaly have been exclusively large missions with heavy payload equipment. With the recent rapid progression of CubeSats, it can be expected that the routine monitoring of the South Atlantic Anomaly will be taken over by CubeSats in the future. We present one-and-a-half years of observations of the South Atlantic Anomaly radiation field measured by a CubeSat in polar orbit with an elevation of 540 km. The position is calculated by an improved centroid method that takes into account the area of the grid. The dataset consists of eight campaigns measured at different times, each with a length of 22 orbits (~2000 min). The radiation data were combined with GPS position data. We detected westward movement at 0.33°/year and southward movement at 0.25°/year. The position of the fluence maximum featured higher scatter than the centroid position.

Highlights

The objective of this study is to prove that 1U CubeSats can be exploited for the longterm monitoring of the South Atlantic Anomaly (SAA) movement, as all measurements introduced in Table 1 were done on professional large satellites
Our results show the average westward movement of the SAA by 0.34°/year, which centroid method is relatively insensitive to the number of measurement points, it would benefit from denser sampling of the SAA region
Our study has demonstrated that small, cost-effective 1U CubeSats can be successfully used for the observation of SAA drift

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The Earth has two van Allen radiation belts, i.e., the inner and outer, which consist of trapped high-energy charged particles. Most of the particles within the radiation belts originate from solar winds and galactic cosmic rays [1]. The approximately dipolar magnetic field at low altitudes generated by Earth’s core is tilted and shifted from the geographic pole. This creates a region with reduced magnetic field intensity, namely the South Atlantic Anomaly (SAA), which is located approximately on the eastern coast of Brazil. The SAA is a place where the radiation of the inner van

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