P. K. Toivanen

P. K. Toivanen
Finnish Meteorological Institute · Earth Observation Programme

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71
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781
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Publications

Publications (71)
Preprint
Full-text available
The design, integration, testing, and launch of the first Finnish satellite Aalto-1 is briefly presented in this paper. Aalto-1, a three-unit CubeSat, launched into Sun-synchronous polar orbit at an altitude of approximately 500 km, is operational since June 2017. It carries three experimental payloads: Aalto Spectral Imager (AaSI), Radiation Monit...
Article
Full-text available
The design, integration, testing and launch of the first Finnish satellite Aalto-1 is briefly presented in this paper. Aalto-1, a three-unit CubeSat, launched into Sun-synchronous polar orbit at an altitude of approximately 500 km, is operational since June 2017. It carries three experimental payloads: Aalto Spectral Imager(AaSI), Radiation Monitor...
Preprint
Full-text available
The in-orbit results and lessons learned of the first Finnish satellite Aalto-1 are briefly presented in this paper. Aalto-1, a three-unit CubeSat which was launched in June 2017, performed AaSI (Aalto Spectral Imager), Radiation Monitor (RADMON), and Electrostatic Plasma Brake (EPB) missions. The satellite partly fulfilled its mission objectives a...
Article
Full-text available
The in-orbit results and lessons learned of the first Finnish satellite Aalto-1 are briefly presented in this paper. Aalto-1, a three-unit CubeSat which was launched in June 2017, performed Aalto Spectral Imager (AaSI), Radiation Monitor (RADMON) and Electrostatic Plasma Brake (EPB) missions. The satellite partly fulfilled its mission objectives an...
Article
Full-text available
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 propulsio...
Article
Full-text available
Today, the near‐Earth space is facing a paradigm change as the number of new spacecraft is literally skyrocketing. Increasing numbers of small satellites threaten the sustainable use of space, as without removal, space debris will eventually make certain critical orbits unusable. A central factor affecting small spacecraft health and leading to deb...
Preprint
Full-text available
Today, the near-Earth space is facing a paradigm change as the number of new spacecraft is literally sky-rocketing. Increasing numbers of small satellites threaten the sustainable use of space, as without removal, space debris will eventually make certain critical orbits unusable. A central factor affecting small spacecraft health and leading to de...
Article
Full-text available
We propose a distributed close-range survey of hundreds of asteroids representing many asteroid families, spectral types and sizes. This can be implemented by a fleet of nanospacecraft (e.g., 4-5-unit CubeSats) equipped with miniature imaging and spectral instruments (from near ultraviolet to near infrared). To enable the necessary large delta-v, e...
Article
Launching orbital and suborbital rockets from a high altitude is beneficial because of e.g. nozzle optimisation and reduced drag. Aeroplanes and gas balloons have been used for the purpose. Here we present a concept where a balloon is filled with pure water vapour on ground so that it rises to the launch altitude. The system resembles a gas balloon...
Conference Paper
This paper is republished in Acta Astronautica as "Coulomb drag propulsion experiments of ESTCube-2 and FORESAIL-1": https://www.researchgate.net/publication/337626758_Coulomb_drag_propulsion_experiments_of_ESTCube-2_and_FORESAIL-1\\ In this paper, a novel, efficient, lightweight and cost-effective method for satellite deorbiting is presented. The...
Article
The shape of a rotating electric solar wind sail under the centrifugal force and solar wind dynamic pressure is modeled to address the sail attitude maintenance and thrust vectoring. The sail rig assumes centrifugally stretched main tethers that extend radially outward from the spacecraft in the sail spin plane. Furthermore, the tips of the main te...
Conference Paper
Full-text available
A voltage-biased metallic tether creates an electrostatic potential structure around itself. If put into flowing plasma, the electrostatic field deflects the trajectories of plasma ions. The resulting momentum transfer from plasma to the tether can be used for propulsive purposes. The electric solar wind sail (E-sail) is one such application. The E...
Article
In Coulomb drag propulsion, a long high voltage tether or system of tethers gathers momentum from a natural plasma stream such as solar wind or ionospheric plasma ram flow. A positively polarised tether in the solar wind can be used for efficient general-purpose interplanetary propellantless propulsion (the electric solar wind sail or E-sail), wher...
Article
The electric solar wind sail (E-sail) is a way to propel a spacecraft by using the natural solar wind as a thrust source. The problem of secular spinrate change was identified earlier which is due to the orbital Coriolis effect and tends to slowly increase or decrease the sail's spinrate, depending on which way the sail is inclined with respect to...
Article
Full-text available
ESTCube-1 is a one-unit CubeSat that has been in orbit since May 2013. It was launched to a Sun-synchronous 670 km altitude polar low Earth orbit, and its primary mission objective was to centrifugally deploy a tether as a part of the first in-orbit demonstration of electric solar wind sail (E-sail) technology. The electrical power system, the comm...
Conference Paper
This conference paper is largely based on "ESTCube-1 In-Orbit Experience and Lessons Learned": https://www.researchgate.net/publication/282356730_ESTCube-1_In-Orbit_Experience_and_Lessons_Learned_Harry_Rowe_Mimno_Award_2016 // ESTCube-1 is a one-unit CubeSat that has been in orbit since May 2013. It was launched to a Sun-synchronous 670 km altitud...
Article
The electric solar wind sail (E-sail) propellantless propulsion device uses long, charged metallic tethers to tap momentum from the solar wind to produce spacecraft propulsion. If flying through planetary or moon eclipse, the long E-sail tethers can undergo significant thermal contraction and expansion. Rapid shortening of the tether increases its...
Article
The electric solar wind sail produces thrust by centrifugally spanned high voltage tethers interacting with the solar wind protons. The sail attitude can be controlled and attitude maneuvers are possible by tether voltage modulation synchronous with the sail rotation. Especially, the sail can be inclined with respect to the solar wind direction to...
Conference Paper
Full-text available
The Electric Solar Wind Sail (E-sail) can produce 0.5-1 N of inexhaustible and controllable propellantless thrust [1]. The E-sail is based on electrostatic Coulomb interaction between charged thin tethers and solar wind ions. It was invented in 2006, was developed to TRL 4-5 in 2011-2013 with ESAIL FP7 project (http://www.electric-sailing.fi/fp7) a...
Article
Full-text available
We show that by having the auxtethers made partly or completely of conducting material and by controlling their voltages, it is possible to control the spin rate of the electric solar wind sail by using the electric sail effect itself. The proposed intrinsic spin rate control scheme has enough control authority to overcome the secular change of the...
Article
Full-text available
This paper presents the mission analysis, requirements, system design, system level test results, as well as mass and power budgets of a 1-unit CubeSat ESTCube-1 built to perform the first in-orbit demonstration of electric solar wind sail (E-sail) technology. The E-sail is a propellantless propulsion system concept that uses thin charged electrost...
Article
Full-text available
The scientific mission of ESTCube-1, launched in May 2013, is to measure the Electric solar wind sail (E-sail) force in orbit. The experiment is planned to push forward the development of E-sail, a propulsion method recently invented at the Finnish Meteorological Institute. E-sail is based on extracting momentum from the solar wind plasma flow by u...
Article
Full-text available
We analyse the potential of the electric solar wind sail for solar system space missions. Applications studied include fly-by missions to terrestrial planets (Venus, Mars and Phobos, Mercury) and asteroids, missions based on non-Keplerian orbits (orbits that can be maintained only by applying continuous propulsive force), one-way boosting to outer...
Chapter
The deployment, dynamics, and control of the electric solar wind sail is addressed in terms of the single tether motion. Based on a simple model of a rotating rigid tether as a spherical pendulum, estimates for the goodness of the control system are shown for strictly planar tether tip orbits. It is concluded that the control system is rather ineff...
Article
Full-text available
The electric solar wind sail is a propulsion system that uses long centrifugally spanned and electrically charged tethers to extract the solar wind momentum for spacecraft thrust. The sail angle with respect to the sun direction can be controlled by modulating the voltage of each tether separately to produce net torque for attitude control and thru...
Article
Full-text available
We analyse the potential of the electric solar wind sail for solar system space missions. Applications studied include fly-by missions to terrestrial planets (Venus, Mars and Phobos, Mercury) and asteroids, missions based on non-Keplerian orbits, one-way boosting to outer solar system, off-Lagrange point space weather forecasting and low-cost impac...
Conference Paper
Full-text available
There are an estimated one to two million asteroids of diameter over 1 km in-between the orbits of Mars and Jupiter. Impact threat, mining prospects and the understanding of solar system history make asteroids interesting objects for further in-situ studies. Electric Solar Wind Sail (E-sail) [1] technology enables touring several different astero...
Conference Paper
Full-text available
Electrostatic plasma brake is a novel tether-based de-orbiting concept especially suitable for satellites with less than 100 kg of mass. It is a spin-off of the Electric Solar Wind Sail (E-sail), invented in 2006 (www.electric-sailing.fi) and consisting of charged tethers transforming solar wind momentum into spacecraft acceleration through Coulomb...
Article
Full-text available
The electric solar wind sail is a propulsion system that uses long centrifugally spanned and electrically charged tethers to extract solar wind momentum for spacecraft thrust. The sail solar zenith angle and phase can be controlled by modulating the voltage of each tether separately to produce net torque for attitude control and thrust vectoring. I...
Article
Full-text available
The electric solar wind sail (E-sail) is a new propulsion technology which was invented in 2006 and which is developed by a European consortium. First flight experiments will be performed onboard Estonian and Finnish CubeSats in 2013-2014, and our aim is to fly a solar wind test mission in 2015-2016. Once developed the E-sail will reduce travel tim...
Conference Paper
Full-text available
http://meetingorganizer.copernicus.org/EPSC-DPS2011/EPSC-DPS2011-1363.pdf Current and planned asteroid missions target only a single, or a few of asteroids, and have consumed their propellant after reaching their targets. We propose here using the new Electric Solar Wind Sail (E-sail) technology in a mission touring several different asteroids wit...
Conference Paper
Full-text available
The Electric Solar Wind Sail (E-sail) is a new propulsion method that uses long, thin and positively charged tethers to turn solar wind momentum flux into spacecraft thrust. The E-sail was invented in 2006 and is currently under development and funded e.g. by the European Union's Seventh Framework Programme for Research and Technological Developmen...
Conference Paper
Full-text available
The Electric Solar Wind Sail (E-sail) is a novel propulsion concept that enables faster space travel to many solar system targets. E-sail uses charged solar wind particles as the source of its propulsion. This is achieved by deploying long, conducting and charged tethers, which get pushed by the solar wind by Coulomb drag [1]. E-sail technology is...
Article
The solar wind kinetic energy fueling all dynamical processes within the near-Earth space is extracted in a dynamo process at the magnetopause. This direct energy transfer from the solar wind into the magnetosphere depends on the orientation of the interplanetary magnetic field (IMF) as well as other solar wind parameters, such as the IMF magnitude...
Article
The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural solar wind dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The conce...
Article
Full-text available
The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural solar wind dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The conce...
Article
Full-text available
In this paper, sailing and navigation in the solar wind with a spacecraft powered by an electric sail is addressed. The electric sail is a novel propellantless spacecraft propulsion concept based on positively charged tethers that are centrifugally uncoiled and stabilised to extract the solar wind momentum by repelling the solar wind protons. Steer...
Article
Presentation of the electromagnetic fields in terms of the Euler potentials is ideal in modelling of the magnetic and electric fields in large-scale magnetospheric plasmas: The electric field consistent with the frozen-in condition including also the contribution arising from the temporal variations of the magnetic field can be easily obtained. Her...
Article
Various deformation methods have been widely used in animation image processing. In common terms, they are mathematical presentations of deformations of an image drawn on an elastic material under stretching or compression of the material. Such a method has also been used in modelling of the magnetospheric magnetic fields, and recently been general...
Article
A new magnetospheric magnetic field model given globally in terms of the Euler potentials is constructed. It complements the preexisting model magnetic fields with a possibility of straightforward inclusion of electric fields, especially those arising from temporal variations of the model magnetic field. The model is based on the deformation method...
Article
In this paper the deformation method for magnetospheric magnetic fields is generalized to electric fields. It has been previously shown that an initial magnetic field configuration can be deformed to another configuration given in original coordinates by expressing the initial field in terms of the deformed coordinates and by multiplying this field...
Article
Full-text available
This paper presents simultaneous observations of 6-mHz magnetic pulsations in the nightside high-latitude plasma sheet, inner plasma sheet at the geosynchronous distance, and auroral region on the ground in association with substorm onset. We study an isolated substorm (AE ∼ 300 nT) onset on 19 October 1999 at ∼0145 UT. The Polar spacecraft was loc...
Article
A new method for modelling of the magnetospheric time-dependent large-scale electric and magnetic fields has been developed. The method is based on a method of magnetic field deformations that has been generalized to also include both the electrostatic and inductive electric fields. In this poster, the mathematical formulation of the method is desc...
Article
We use Cluster II observations of magnetic and electric fields to study the electric field characteristics in the magnetotail. Emphasis of this study is in the central plasma sheet and at the plasma sheet boundary. We investigate the electric field properties such as wave field characteristic frequencies and amplitudes, and DC field magnitudes. The...
Article
A new method for modelling of the magnetospheric time-dependent large-scale electric and magnetic fields has been developed. The method is based on a method of magnetic field deformations that has been generalized to also include both the electrostatic and inductive electric fields. Here the method will be demonstrated by introducing a new model...
Article
Large electromagnetic pulsations near and at the plasma sheet boundary midway be- tween the ionosphere and equatorial plasma sheet are often observed during sub- storms. In this study, we use observations of the Polar spacecraft together with ground based networks to show evidence that the field variations are initiated at the substorm onset and ar...
Article
Full-text available
We present observations of the Polar spacecraft of magnetospheric substorm signatures in the plasma sheet midway along auroral field lines between the ionosphere and the equatorial plasma sheet. On October 17, 1997, Polar was located in the onset meridian in conjunction with the Scandinavian magnetometer chain (International Monitor for Auroral Geo...
Article
Full-text available
An isolated substorm on Oct. 17, 1997 during a close conjunction of the Polar spacecraft and the ground-based MIRACLE network is studied in detail. We identify signatures of substorm onset in the plasma sheet midway between the ionosphere and the equatorial plasma sheet, determine their timing relative to the ground signatures, and discuss their co...
Conference Paper
Full-text available
The state-of-the-art plasma instruments on the POLAR spacecraft provide high resolution observations of short bursts of transverse plasma motion midway between the auroral acceleration region and the plasma sheet. At this location, short duration (< one minute) intervals of strong transverse ion convection are observed on the nightside during all p...
Article
We use a bounce-averaged drift model with realistic electromagnetic fields together with magnetic field and electron data obtained by CRRES to study energetic electron distributions during the growth phase of an isolated substorm on December 12, 1990. The magnetic field model includes the actual time evolution of the geomagnetic field as measured b...
Article
In this paper we use the Concept of the Faraday loop to connect the ionosphere and the tail along the geomagnetic field lines to study the coupling between ionospheric and magnetospheric electric fields. The formulation using the Faraday loop shows that the coupling consists of three contributions: One is the familiar mapping of the ionospheric fie...
Conference Paper
Full-text available
Between 10 and 11 UT On September 3, 1997, the POLAR satellite crossed the equatorial magnetosphere at 1500 local time. Three components of the H + and O + ion distribution observed at L= 4 had broad maxima in the number flux at 12, 50 and 120 keV/e. Such multiple peaked ion distributions are frequently observed in the dusk side magnetosphere. We u...
Article
Large-scale electric field contributes to the charged particle drift motion directly through the E×B drift and indirectly through energization caused by magnetic drifts parallel to the electric field and through pitch angle changes due to magnetic field gradients perpendicular to the electric field. In this paper, we describe these effects on parti...
Article
Full-text available
PROMICS-3 is a plasma experiment flown in the Russian project Interball. It performs three-dimensional (3D) measurements of ions in the energy range 4 eV–70 keV with mass separation and of electrons in the energy range 12 eV–35 keV. The Interball project consists of two main satellites, the Tail Probe and the Auroral Probe, each with one subsatelli...
Article
Full-text available
There are good reasons to expect that parallel electric fields have significant effects during the substorm process both above the auroral ionosphere and in the far tail. During the substorm growth phase the upward field-aligned current (FAC) in the midnight-premidnight sector intensifies. According to the current-voltage relationship in upward FAC...
Article
Full-text available
In this paper we describe an empirical model for the nightside magnetopsheric electric field to be used with time-evolving magnetospheric magnetic field models during the substorm growth phase. We use a substorm event on 4 March, 1979 to determine the model: We apply a simple model for the enhancing two cell structure of the ionospheric electric fi...
Article
The GEOTAIL spacecraft has previously observed cold ion beams of apparent ionospheric origin in the Earth's magnetotail lobes at large geocentric distances (r > 50 RE). It is proposed here that ion beams originating in certain sections of the polar ionosphere may be on magnetic flux tubes that are not closely linked to the magnetosheath and solar w...
Article
We have studied 11 substorm recovery phase events in which magnetic field and energetic particle data were available near the midnight sector from the GEOS 2 satellite. Comparison with the Tsyganenko magnetic field model shows that, after the expansion phase, BZ is large and decreases gradually toward the model value during the recovery phase, wher...

Projects

Projects (4)