Towards in-orbit hyperspectral imaging of space debris

Satellites are vulnerable to space debris larger than ~1 cm, but much of this debris cannot be tracked from the ground. In-orbit detection and tracking of debris is one solution to this problem. We present some steps towards achieving this, and in particular to use hyperspectral imaging to maximise the information obtained. We present current work related to hyperspectral in-orbit imaging of space debris in three areas: scenario evaluation, a reflectance database, and an image simulator. Example results are presented. Hyperspectral imaging has the potential to provide valuable additional information, such as assessments of spacecraft or debris condition and even spectral “finger-printing” of material types or use (e.g. propellant contamination). These project components are being merged to assess mission opportunities and to develop enhanced data processing methods to improve knowledge and understanding of the orbital environment

HySim: a tool for space-to-space hyperspectral resolved imagery

This paper introduces HySim, a novel tool addressing the need for hyperspectral space-to-space imaging simulations, vital for in-orbit spacecraft inspection missions. This tool fills the gap by enabling the generation of hyperspectral space-to-space images across various scenarios, including fly-bys, inspections, rendezvous, and proximity operations. HySim combines open-source tools to handle complex scenarios, providing versatile configuration options for imaging scenarios, camera specifications, and material properties. It accurately simulates hyperspectral images of the target scene. This paper outlines HySim's features, validation against real space-borne images, and discusses its potential applications in space missions, emphasising its role in advancing space-to-space inspection and in-orbit servicing planning.UK Defence and Security Accelerator (DASA

(De)Touring Europe: The Balkan, The Postcolonial and Christos Tsiolkas’s Dead Europe

This article will interrogate the fictional mobilisation of ‘the Balkan’ as a trope in Christos Tsiolkas’s novel Dead Europe. Reversing the conventions of European travel writing, the novel stages a shambolic Grand Tour of vampiric contamination, which exposes the vacuity of Europe’s self-professed ideals of progress, rationality and liberalism. Whilst bearing the imprint of a recognisable Balkanist rhetoric which locates the origins of racial prejudice in a Second World War Greek village and the excesses of conspicuous consumption in a contemporary Athens, Dead Europe also presents ‘the Balkan’ as a disruptive medium which jostles the Australian protagonist out of his political complacency and awakens him to his own visceral, if spectral, relation to prejudice. ‘The Balkan’ in this set-up does not function as a mere backdrop to identify against; rather, it is a site of a radical interrogation of the coherence, boundedness and erasures of the (Australian and European) self – an interrogation that confronts without offering a solution or redemption

Hammett Structural Relationships Revealed in Chalcogen Bonded Co-crystals of Electron Rich Pyridines with 4′-Substituted Ebselen Derivatives

In this work, a detailed Hammett structure-structure correlation was applied to a range of chalcogen bonded co-crystals prepared by combining 4′-substituted derivatives of the selenium-based drug ebselen with three different 4-amino-substituted pyridine based chalcogen bond acceptors of differing basicities. This established that the N · · · Se chalcogen bond distance is well within the sum of the van der Waals radii of Se and N and is sensitive to the electronic nature of the substituent. Thus N · · · Se distances ranging from 2.2424(5)–2.4496(9) Å were observed with the shorter distances being observed in co-crystals of ebselen substituted with electron withdrawing groups. Associated with trends of the N · · · Se distance as a function of the 4′-substituent was lengthening of the internal Se−N bond distance consistent with a significant covalent contribution to N · · · Se chalcogen bonding in these derivatives. We define a covalency quotient for the chalcogen bond as the negative slope of the plot of the internal Se−N bond distance vs the external N · · · Se chalcogen bond distance. A value of 0.31 was obtained implying a significant covalent contribution to N · · · Se chalcogen bond. A similar result was obtained by an analysis of chalcogen bonded selenium containing molecules harvested from the Cambridge Crystallographic Database. The covalency quotient is extended to the general case for sigma-hole interactions including halogen bonding and hydrogen bonding, and we show that the covalent component of such interactions can be inferred from the lengthening of the donor bond. The degree of charge transfer in a smaller number of chalcogen bonded co-crystals of ebselen was established by measuring experimental electron density using high-resolution x-ray diffraction to more accurately measure the degree of electron transfer and hence covalency. This showed that in the most strongly bound systems, up to 1 electron worth of charge is transferred from the Lewis base to the Ch-bond donor, which again clearly points to significant covalent character

Reactions of Thiiranium and Sulfonium Ions with Alkenes in the Gas Phase

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