Coulomb drag propulsion experiments of ESTCube-2 and FORESAIL-1

This paper presents two technology experiments – the plasma brake for deorbiting and the electric solar wind sail for interplanetary propulsion – on board the ESTCube-2 and FORESAIL-1 satellites. Since both technologies employ the Coulomb interaction between a charged tether and a plasma flow, they are commonly referred to as Coulomb drag propulsion. The plasma brake operates in the ionosphere, where a negatively charged tether deorbits a satellite. The electric sail operates in the solar wind, where a positively charged tether propels a spacecraft, while an electron emitter removes trapped electrons. Both satellites will be launched in low Earth orbit carrying nearly identical Coulomb drag propulsion experiments, with the main difference being that ESTCube-2 has an electron emitter and it can operate in the positive mode. While solar-wind sailing is not possible in low Earth orbit, ESTCube-2 will space-qualify the components necessary for future electric sail experiments in its authentic environment. The plasma brake can be used on a range of satellite mass classes and orbits. On nanosatellites, the plasma brake is an enabler of deorbiting – a 300-m-long tether fits within half a cubesat unit, and, when charged with -1 kV, can deorbit a 4.5-kg satellite from between a 700- and 500-km altitude in approximately 9–13 months. This paper provides the design and detailed analysis of low-Earth-orbit experiments, as well as the overall mission design of ESTCube-2 and FORESAIL-1.Peer reviewe

Coulomb drag propulsion experiments of ESTCube-2 and FORESAIL-1

This paper presents two technology experiments – the plasma brake for deorbiting and the electric solar wind sail for interplanetary propulsion – on board the ESTCube-2 and FORESAIL-1 satellites. Since both technologies employ the Coulomb interaction between a charged tether and a plasma flow, they are commonly referred to as Coulomb drag propulsion. The plasma brake operates in the ionosphere, where a negatively charged tether deorbits a satellite. The electric sail operates in the solar wind, where a positively charged tether propels a spacecraft, while an electron emitter removes trapped electrons. Both satellites will be launched in low Earth orbit carrying nearly identical Coulomb drag propulsion experiments, with the main difference being that ESTCube-2 has an electron emitter and it can operate in the positive mode. While solar-wind sailing is not possible in low Earth orbit, ESTCube-2 will space-qualify the components necessary for future electric sail experiments in its authentic environment. The plasma brake can be used on a range of satellite mass classes and orbits. On nanosatellites, the plasma brake is an enabler of deorbiting – a 300-m-long tether fits within half a cubesat unit, and, when charged with - 1 kV, can deorbit a 4.5-kg satellite from between a 700- and 500-km altitude in approximately 9–13 months. This paper provides the design and detailed analysis of low-Earth-orbit experiments, as well as the overall mission design of ESTCube-2 and FORESAIL-1.</p

Foresail-2 Piensatelliitin Lähetin-Vastaanotin Etupään Suunnittelu

The rapid growth of the space industry alongside technological developments is producing more capable satellite systems with increasingly complex missions and requirements. This development shifts typical small satellite operating frequencies from VHF (Very High Frequency) and UHF (Ultra High Frequency) bands to higher frequency bands such as S-band due to improved data rates and efficiency. This thesis presents a designed S-band radio frequency front-end for the Foresail-2 small satellite. The conducted mission analysis resulted in requirements for the radio front-end, such as an output power of 30 dBm, full-duplex communication capabilities and a variable data rate. These were found necessary due to the highly elliptical nature of the GTO (Geostationary Transfer Orbit) orbit of the satellite in addition to international radio regulations. The operating frequency of the front-end was chosen at 2.08 GHz (RX) and 2.28 GHz (TX). The performance of the chosen and designed elements, based on these requirements were found to be capable of producing a viable front-end design for the satellite mission. The chosen power amplifier achieved a power output level of 32 dBm prior to saturation and the designed microstrip low pass, band pass and band stop filters had performance characteristics comparable to their simulated values. The estimated receiver noise figure of the system, based on simulated and stated performance values is 1.85 dB. The work conducted in this thesis provides a starting point for the radio front-end design of Foresail-2, that meets the derived radio system requirements of the mission.Avaruusalan nopea kasvu teknisen kehityksen myötä on johtanut edistyksellisempiin satelliittijärjestelmiin entistä vaativampia ja monimutkaisempia satelliittimissioita varten. Tämä kehitys siirtää tyypillisiä piensatelliittien toimintataajuuksia VHF (Very High Frequency) ja UHF (Ultra High Frequency) kaistoilta korkeammille taajuuskaistoille kuten S-kaistalle, jolla saavutetaan korkeammat tiedonsiirtonopeudet ja tehokkuudet. Tämä työ esittää Foresail-2 piensatelliittimissiolle suunnitellun S-kaistan radiojärjestelmän etupään suunnittelun. Työssä tehty missioanalyysi johti sellaisiin radiojärjestelmän vaatimuksiin, kuten 30 dBm:n lähtöteho, kahdensuuntainen samanaikainen kommunikaatiokyvykkyys, sekä säädettävä tiedonsiirtonopeus. Nämä vaatimukset todettiin tarpeellisiksi johtuen satelliittimission hyvin elliptisestä, GTO (Geostationary Transfer Orbit) radasta, sekä kansainvälisistä radiomääräyksistä. Radiojärjestelmän taajuuksiksi valittiin 2.08 GHz (vastaanotto) ja 2.28 GHz (lähetys). Näiden vaatimusten perusteella suunnitellut ja valitut komponentit, sekä niiden suorituskyky todettiin riittäväksi tuottamaan toimiva radiojärjestelmän etupää satelliittimissiota varten. Valittu radiojärjestelmän vahvistin saavutti 32 dBm:n saturoimattoman lähtötehon ja suunnitellut mikroliuska alipäästö, kaistanpäästö ja kaistanesto suodattimet tuottivat suorituskyvyn, joka vastasi simulaatioista saamia tuloksia. Vastaanottimen kohinaluku on 1.85 dB, perustuen komponenttien sekä simulaatioista saamiin suorituskykyarvoihin. Työ, joka tässä opinnäytetyössä on tehty, toimii lähtökohtana Foresail-2 mission radiojärjestelmän etupään suunnittelulle, joka täyttää työssä johdetut satelliittimission radiojärjestelmän vaatimukset

Foresail-2: Space Physics Mission in a Challenging Environment

Earth’s radiation belts are extremely important for space weather because they can store and accelerate particles to relativistic energies, which can have a potential impact on satellite functionality, communications, and navigation systems. The FORESAIL consortium wants to measure these high-energy particle fluxes to understand the dynamics of the radiation belts with its satellite mission Foresail-2. The mission aims to measure magnetic ultra low frequency waves and the plasma environment in the magnetosphere around Earth. The captured data will help to improve our understanding of space weather, and in particular the dynamics of Earth’s radiation belts during periods of large disturbances inside the magnetosphere. A mission design analysis and several trade-off studies are conducted to find the requirements for the science payloads and spacecraft avionics design. Deducted from these requirements, four different payloads are proposed to gather science data in a highly elliptical orbit such as a geostationary transfer orbit. The precision magnetometer uses flux-gate technology to measure magnetic waves from 1 mHz to 10 Hz. The spin scanning particle telescope is built around a detector stack to measure electron spectra in the range of 30 keV to 10 MeV. Additionally, this mission serves as a technology demonstrator for the Coulomb drag experiment which proposes a new kind of electric solar wind sail utilising the Coulomb drag force imposed onto a 300 m long tether. The fourth payload investigates multilayer radiation shielding and single event effects. All payloads will be supported by a newly developed 6U platform using mostly commercial off-the-shelf components. Its proposed avionics face several unique design requirements rising from the payloads and the preferred highly elliptical orbit for this mission.Peer reviewe