0000000000548168

AUTHOR

Pekka Janhunen

0000-0001-5650-8039

showing 4 related works from this author

Nano-graphite cold cathodes for electric solar wind sail

2015

The nanographite (NG) films consisting of tiny graphite crystallites (nanowalls) are produced by carbon condensation from methane–hydrogen gas mixture activated by a direct current discharge. High aspect ratio and structural features of the NG crystallites provides efficient field electron emission (FE). Applicability and performance of the NG films in an electron gun (E-gun) of a solar wind thruster system with an electric sail (E-sail) is tested. The long-term tests are demonstrated suitability of E-gun assembly with the NG cathodes for the real space missions. The results of the tests are analyzed and physical mechanisms of the cathode aging and practical methods for improvement performa…

nanographite filmsMaterials scienceta114ta221Analytical chemistrychemistry.chemical_elementsolar wind thruster systemGeneral ChemistryCathodelaw.inventionField electron emissionchemistrylawGeneral Materials ScienceElectric sailDirect-current dischargeCrystalliteGraphiteComposite materialCarbonElectron gunCarbon
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Aalto-1, multi-payload CubeSat: Design, integration and launch

2021

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 (RADMON), and Electrostatic Plasma Brake (EPB). AaSI is a hyperspectral imager in visible and near-infrared (NIR) wavelength bands, RADMON is an energetic particle detector and EPB is a de-orbiting technology demonstration payload. The platform was designed to accommodate multiple payloads while ensuring sufficient data, power, radio, mechanica…

Computer sciencePolar orbitFOS: Physical sciencesAerospace Engineering02 engineering and technologyDesign strategy01 natural sciences7. Clean energyPhysics - Space Physicsmittauslaitteet0203 mechanical engineering0103 physical sciencesBrakeAalto-1CubeSatGround segmentAerospace engineeringInstrumentation and Methods for Astrophysics (astro-ph.IM)010303 astronomy & astrophysicsavaruustekniikkaAalto spectral imagerRadiation monitortutkimussatelliitit020301 aerospace & aeronauticsRadiationSpacecraftbusiness.industryPayloadCubeSatElectrostatic plasma brakesäteilySpace Physics (physics.space-ph)satelliititHyperspectralSatelliteAstrophysics - Instrumentation and Methods for Astrophysicsbusinesskosminen säteily
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E-sail test payload of the ESTCube-1 nanosatellite

2014

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 the E-sail, a propulsion method recently invented at the Finnish Meteorological Institute. The E-sail is based on extracting momentum from the solar wind plasma flow by using long thin electrically charged tethers. ESTCube-1 is equipped with one such tether, together with hardware capable of deploying and charging it. At the orbital altitude of ESTCube-1 (660–680 km) there is no solar wind present. Instead, ESTCube-1 shall observe the interaction between the charged tether and the ionospheric plasma. The E…

Physicsta114Payloadbusiness.industryGeneral EngineeringPropulsionlaw.inventionSlip ringSolar windlawElectric sailAerospace engineeringIonosphereSpace researchbusinessVoltageProceedings of the Estonian Academy of Sciences
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ESTCube-1 in-orbit experience and lessons learned

2015

ESTCube-1 is a student satellite project lead by the University of Tartu, Estonia, and supported by the European Space Agency (ESA) via Plan for European Cooperating States (PECS). Development of ESTCube-1 has been a collaborative effort with many international partners. The satellite is shown on Figure 1 [1].

Engineeringta115ta213business.industrynanosatelliteCubeSatE-sailAerospace EngineeringPlan (drawing)satellite designelectric solar wind sailsatellitesESTCube-1AeronauticsSpace and Planetary ScienceAgency (sociology)Space techniquesSatelliteElectrical and Electronic EngineeringOrbit (control theory)Aerospace engineeringelectric solar wind sailsbusinessSpace researchIEEE Aerospace and Electronic Systems Magazine
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