Browsing by Author "Polkko, Jouni"

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  • Coulomb drag propulsion experiments of ESTCube-2 and FORESAIL-1
    (2020-12) Iakubivskyi, Iaroslav; Janhunen, Pekka; Praks, Jaan; Allik, Viljo; Bussov, Kadri; Clayhills, Bruce; Dalbins, Janis; Eenmäe, Tõnis; Ehrpais, Hendrik; Envall, Jouni; Haslam, Sean; Ilbis, Erik; Jovanovic, Nemanja; Kilpua, Emilia; Kivastik, Joosep; Laks, Jürgen; Laufer, Philipp; Merisalu, Maido; Meskanen, Matias; Märk, Robert; Nath, Ankit; Niemelä, Petri; Noorma, Mart; Mughal, Muhammad Rizwan; Nyman, Samuli; Pajusalu, Mihkel; Palmroth, Minna; Paul, Aditya Savio; Peltola, Tatu; Plans, Mathias; Polkko, Jouni; Islam, Quazi Saimoon; Reinart, Anu; Riwanto, Bagus; Sammelselg, Väino; Sate, Janis; Sünter, Indrek; Tajmar, Martin; Tanskanen, Eija; Teras, Hans; Toivanen, Petri; Vainio, Rami; Väänänen, Mika; Slavinskis, Andris
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    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.
  • Ilmatieteen laitoksen Avaruuslaboratorion painereferenssimittarin kalibrointi
    (2011) Kahanpää, Henrik
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Pressure and humidity measuring instrument for MARS-94 penetrating probe
    (1995) Polkko, Jouni
     Helsinki University of Technology | Master's thesis
  • The quality of the Mars Phoenix pressure data
    (2020-02) Kahanpää, Henrik; Polkko, Jouni; Daly, Michael
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The Phoenix lander operated on the surface of Mars for circa 5 months in 2008. One of its scientific instruments is an atmospheric pressure sensor called MET-P. We perform a comprehensive study to identify all error sources affecting the data measured by MET-P and to generate methods for compensating these errors. Our results show that MET-P performed much better than was reported immediately after the mission (Taylor et al., 2010). The error limits of the original calibrated Phoenix pressure data currently available in NASA's Planetary Data System (Dickinson, 2008) are from −5.3 Pa to +3.5 Pa. Further, almost no temperature-dependent error exists in the original calibrated MET-P data. However, we identify a previously unknown error source, temperature hysteresis, which causes minor peaks in the measured pressure curve (<0.4 Pa). The electronic supplementary material of this article contains a version of the Phoenix pressure data generated by applying all the error compensations developed in this study (Online Resource 1). The study is based on the re-analysis of the original test data of MET-P, the analysis of the engineering data measured during the mission on Mars and during the interplanetary cruise, and laboratory tests with the Reference Model of the MET-P sensor. Temperature dependent errors are evaluated by comparing the readings of two sensor heads with different sensitivities, measuring the same quantity. The principle of this method is applicable also for other types of instruments.