NATIONAL INSTITUTE FOR SPACE RESEARCH – INPE/MCT

1. NATIONAL INSTITUTE FOR SPACE RESEARCH – INPE/MCT SOUTHERN REGIONAL SPACE RESEARCH CENTER – CRS/INPE - MCT SOUTHERN SPACE OBSERVATORY – OES/CRS/INPE – MCT FEDERAL UNIVERSITY OF SANTA MARIA – UFSM CENTER OF TECHNOLOGY SPACE SCIENCE LABORATORY OF SANTA MARIA - LACESM/CT – UFSM Analysis of possible failures in satellites Cubesats caused by space environment - I. • Lucas Lourencena Caldas Franke1 , Nelson Jorge Schuch1 , Otavio Santos Cupertino Durão 2 , Lucas Lopes Costa1 , • Eduardo Escobar Bürger1 , Rubens Z. G. Bohrer1 , TarelliRonan Coelho Stekel1 • 1 - Southern  Regional  SpaceResearchCenter - CRS/INPE- MCT,  in  collaborationwiththe  Santa  Maria  SpaceScienceLaboratory - LACESM/CT - UFSM,  Santa  Maria,  RS,  Brazil. • 2 - National Institute for Space Research - CPA/INPE, São José dos Campos, SP, Brazil • lfranke@lacesm.ufsm.br ABSTRACT When a satellite is in orbit, it remains in direct contact with a hostile environment. An analyzes of possible failures that have occurred with CubeSat class satellites due to this exposure is presented. These small satellites have 10cm cubic form and about 1.33 kilograms, they have all subsystems integrated on a single module that fits in the available intern volume, using high technology of miniaturization. Generally, these satellites are launched at a 650km (LEO) altitude orbits. At this range, one of the biggest problems that may affect satellites is the precipitation of charged particles, and this may cause the failure of subsystems and magnetic interference in equipments, with emphasis to natural causes as the impact of solar activity (the solar cycle, solar flares, coronal mass ejections, etc.) and the interference of the South Atlantic Magnetic Anomaly, knowing that the majority of CubeSat’s orbits intersect at some point the acting Anomaly region. The analysis consist of a statistical survey of thirty nine CubeSats already launched, taking into account their actual conditions, giving results of the most common causes and issues that have occurred with them, including the relationship with larger satellites of all kinds, thus contributing for the success and optimization of future CubeSats missions. INTRODUCTION A statistical analysis of 39 CubeSats-Class vulnerabilities was evaluated for the period from 2003 to 2009. As the resources this satellite class are limited, most of the failures and losses that occurred had no conclusive explanation. For this purpose, It was made a register of CubeSat faults and correlated with the solar activity, especially with the extreme solar particle phenomena (EMC, Solar Wind , etc.). At times of solar maximum, solar radiation (Flare) released can reach 6 × 1025J. It’s high energy can cause, mainly in CubeSats, the mission loss. Whereas satellites CubeSats don’t have any type of shielding it is not necessary to have a large solar storm to cause damage to them, a simple change in solar activity would be enough to cause interference or their mission failure. The Fig. 1 shows the relationship between the shielding of some satellites with the precipitation of particles that reach the subsystems, knouting that most of the orbits of CubeSats have an angle of 98 ° and altitude of about 700km (LEO), which fits in the penultimate item in the chart of Fig. 1. The Fig. 2 shows a specific type of CubeSat, with only five subsystems. RESULTS By analyzing and correlating the solar activity peaks, measured by GOES satellites, with the CubeSats operational status, it was exanimate some kind of failures, taking into account failures due to: signal loss, failures in the power subsystem and satellite loss signal. The CubeSats class are directly affected by the interference of the space environment, as well as because they do not have any structure shielding since the satellite's internal subsystems are very fragile. Beyond solar activity each year, there is also the factor of SAMA (South Atlantic Magnetic Anomaly) region effects because most of the CubeSats orbits cross sometime in this SAMA region. The SAMA region is a phenomenon that undermines the vector H of the geomagnetic field, it’s current center is located near the south of Brazil. The SAMA origin is still not entirely clear, but is based on the weakening of the clusters in the liquid part of the Earth interior and follows the logic of secular variation, which according to the observation of geomagnetic data throughout the system is drifting westward because of the difference in speed between the Earth’s outer core and mantel.The abnormality, increases positively charged particles (protons) in the Van Allen belts, which invades the region of the satellite system damaging their altitude in the Anomaly region, it is more intense between 1000km to 2000km in height, but the precipitation of particles and turbulence in the ionosphere may reach to a lower altitudes, which increases the chances for particles precipitation coming from space and therefore increasing the chance for failure of some small satellite subsystems and the mission failure. Fig 2 – Example for a CubeSatstructue with only five subsystems: payload, transceiver, power system, board computer and thermal system. Fig 1 - Relationship between the shielding and particle precipitation from Space Weather Effects On Spacecraft Systems (Barth, J. L.) Fig 4 - The satellite failures concentration in the South Atlantic Magnetic Anomaly – SAMA region Internet link: www.ngdc.noaa.gov/stp/satellite/anomaly/doc/sts.pdf Currently the Sun is in low solar activity, however, the forecast for 2012 is that some solar storms will occur disturbing the Geospace and probably will damage satellites, therefore this search and analysis will be continued to collect more consistent satellite failure data and its causes The fig 5 shows the solar activity, sunspot number, and model prediction for the period from 1998 to 2020. METHODOLOGY Some data and conclusions were obtained through literature and home pages search: (http://mtech.dk/thomsen/space/cubesat.php) and (http://www.amsat.org/amsat-new/satellites/ cubesats.php), and e-mails contacts with international institutions personal that have launched CubeSats. The Solar activity data for the period of 2003 to 2009 was obtained from the GOES satellites (Geostationary Operational Environmental Satellites) pages. The functionality and parameters of CubeSats was obtained from the CubeSat forum (www.cubesat.org). From these data, it was made a statistical analysis to correlation the Solar data with the CubeSatsfailures . Fig. 5: The solar activity, sunspot number, and model prediction for the period from 1998 to 2020 by NOAA satellites. Internet link: http://hflink.com/ssn_predict.gif 38th COSPAR SCIENTIFIC ASSEMBLY BREMEN, GERMANY 18-25 July 2010 Fig 3 – The 39 CubeSats launch around the world, from 2003 to 2009, and their present operational status