FORESAIL-1 cubesat mission to measure radiation belt losses and demonstrate de-orbiting

Abstract 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 debris is the radiation environment, which is unpredictable due to an incomplete understanding of the near-Earth radiation environment itself and its variability driven by the solar wind and outer magnetosphere. This paper presents the FORESAIL-1 nanosatellite mission, having two scientific and one technological objectives. The first scientific objective is to measure the energy and flux of energetic particle loss to the atmosphere with a representative energy and pitch angle resolution over a wide range of magnetic local times. To pave the way to novel model - in situ data comparisons, we also show preliminary results on precipitating electron fluxes obtained with the new global hybrid-Vlasov simulation Vlasiator. The second scientific objective of the FORESAIL-1 mission is to measure energetic neutral atoms (ENAs) of solar origin. The solar ENA flux has the potential to contribute importantly to the knowledge of solar eruption energy budget estimations. The technological objective is to demonstrate a satellite de-orbiting technology, and for the first time, make an orbit manoeuvre with a propellantless nanosatellite. FORESAIL-1 will demonstrate the potential for nanosatellites to make important scientific contributions as well as promote the sustainable utilisation of space by using a cost-efficient de-orbiting technology.Peer reviewe

The supercovering relation, the pairwise winner, and more missing links between Borda and Condorcet

Among all existing paradoxes of voting, the one pointed out by Condorcet has managed to become known as 'the' voting paradox. This relevant paradox states that the transitivity of the voters' preferences does not imply the transitivity of the collective preference. However, this collective preference disregards a considerable part of the information provided by the voters. Here, we propose a new way of comparing candidates-resulting in the supercovering relation-that, although it might not be complete, avoids the voting paradox and further restricts the ubiquitous covering relation. Thus the pairwise winner emerges, a new natural type of winner situated in between the Condorcet winner and the unanimous winner. This pairwise winner turns out to serve as a cornerstone of social choice theory that finally unites the Borda winner and the Condorcet winner. Moreover, we analyse an interesting superset of the uncovered set-the unsupercovered set-and we propose a method for selecting candidates from this set, resulting in the introduction of the notion of a P-optimal candidate