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Astrodynamics

Article Title

Smart dust option for geomagnetic tail exploration

Keywords

smart dust, femto solar sail, electrochromic control system, geomagnetic tail exploration

Abstract

In-situ measurements are necessary for a long-term analysis of the spatial structure of thegeomagnetic tail. This type of mission requires the use of a propellantless propulsion system,such as a classical solar sail, to continuously rotate the design orbit apse line such thatit remains parallel to the Sun–Earth direction. To reduce the mission costs, this papersuggests the employment of Sun-pointing smart dusts, which are here investigated in termsof propulsive acceleration level necessary to guarantee a mission’s feasibility. A Sun-pointingsmart dust can be thought of as a millimeter-scale solar sail, whose geometric configurationallows it to passively maintain an alignment with the Sun–spacecraft line. The smart dustexternal surface is coated with an electrochromic reflective film in such a way that it maychange, within some limits, its propulsive acceleration magnitude. A suitable control lawis necessary for the smart dust to enable an artificial precession of its Earth-centred orbit,similar to what happens in the GeoSail mission. This paper analyzes the required controllaw using an optimal approach. In particular, the proposed mathematical model provides aset of approximate equations that allow a simple and effective tradeoff analysis between thepropulsive requirements, in terms of the smart dust acceleration, and the characteristics ofthe design orbit.

Publisher

Tsinghua University Press

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