Passive sorting of asteroid material using solar radiation pressure

Understanding dust dynamics in asteroid environments is key for future science missions to asteroids and, in the long-term, also for asteroid exploitation. This paper proposes a novel way of manipulating asteroid material by means of solar radiation pressure (SRP). We envisage a method for passively sorting material as a function of its grain size where SRP is used as a passive in-situ ‘mass spec-trometer’. The analysis shows that this novel method allows an effective sorting of regolith material. This has immediate applications for sample return, and in-situ resource utilisation to separate different regolith particle sizes

Near Earth asteroid resource utilisation for large in-orbit reflectors

The resources offered by the family of near Earth asteroids could provide bulk materials to support future space science ventures, both crewed missions and space-based astronomy. Using low-energy transfer trajectories small near Earth asteroids could be captured directly, or their material resources returned to Earth orbit or the Lagrange points. With novel fabrication methods, such as additive layer manufacturing, large-scale space structures including optical and radio telescopes could in principle be assembled from such resources. Indeed, with bulk materials readily available, very large numbers of structures could be fabricated in-situ for interferometry applications

Easily retrievable objects among the NEO population

Asteroids and comets are of strategic importance for science in an effort to understand the formation, evolution and composition of the Solar System. Near-Earth Objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The exploitation of these resources has long been discussed as a means to lower the cost of future space endeavours. In this paper, we consider the currently known NEO population and define a family of so-called Easily Retrievable Objects (EROs), objects that can be transported from accessible heliocentric orbits into the Earth’s neighbourhood at affordable costs. The asteroid retrieval transfers are sought from the continuum of low energy transfers enabled by the dynamics of invariant manifolds; specifically, the retrieval transfers target planar, vertical Lyapunov and halo orbit families associated with the collinear equilibrium points of the Sun-Earth Circular Restricted Three Body problem. The judicious use of these dynamical features provides the best opportunity to find extremely low energy Earth transfers for asteroid material. A catalogue of asteroid retrieval candidates is then presented. Despite the highly incomplete census of very small asteroids, the ERO catalogue can already be populated with 12 different objects retrievable with less than 500 m/s of Δv. Moreover, the approach proposed represents a robust search and ranking methodology for future retrieval candidates that can be automatically applied to the growing survey of NEOs

On the a and g families of symmetric periodic orbits in the photo-gravitational hill problem and their application to asteroids

This paper focuses on the exploration of families of planar symmetric periodic orbits around minor bodies under the effect of solar radiation pressure. For very small asteroids and comets, an extension of the Hill problem with Solar Radiation Pressure (SRP) perturbation is a particularly well-suited dynamical model. The evolution of the a and g families of symmetric periodic orbits has been studied in this model when SRP is increased from the classical problem with no SRP to levels corresponding to current and future planned missions to minor bodies, as well as one extreme case with very large SRP. In addition, the feasibility an applicability of these orbits for the case of asteroids was analysed, and the effect of SRP in their stability is presented

'Obesities': Position statement on a complex disease entity with multifaceted drivers

Academic medicine fosters research that moves from discovery to translation, at the same time as promoting education of the next generation of professionals. In the field of obesity, the supposed integration of knowledge, discovery and translation research to clinical care is being particularly hampered. The classification of obesity based on the body mass index does not account for several subtypes of obesity. The lack of a universally shared definition of "obesities" makes it impossible to establish the real burden of the different obesity phenotypes. The individual's genotype, adipotype, enterotype and microbiota interplays with macronutrient intake, appetite, metabolism and thermogenesis. Further investigations based on the concept of differently diagnosed "obesities" are required