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Andrea Viale Gilles Bailet Matteo Ceriotti Colin McInnes 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(12):4142-4157
Future space ventures will likely require exploitation of near-Earth asteroid resources. Moreover, it can be envisaged that asteroids may host habitats in their interiors. In fact, a cavern inside an asteroid would be a natural radiation shield against cosmic radiation and may also serve as a confined environment for storage of mined material such as water ice or other processed volatiles such as propellants. To this end, this paper proposes to leverage the asteroid rotational self-energy to remove material from the asteroid interiors and create a spherical cavern, by means of the orbital siphon concept. The siphon is a chain of tether-connected payload masses (the asteroid material), which exploits the rotation of the asteroid for the delivery of mass from the asteroid to escape. Under certain conditions the siphon can be initiated to ensure self-sustained flow of mass from the asteroid to escape. A net orbital siphon effect is generated by connecting new payloads at the bottom of the chain while releasing the upper payloads. Key parameters are discussed, such as the required siphon dimension and the maximum size of the internal cavity that can be excavated, as a function of the asteroid rotational period. Moreover, assuming elastic material behaviour, a closed-form expression for the stress tensor is found and a failure criterion is used to identify regions in the asteroid interiors subjected to the larger stresses. It is shown that the conditions for failure are relaxed as the radius of the internal void increases. 相似文献
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Matteo Ceriotti Gregory May-Wilson 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(9):2865-2877
The direction and magnitude of a solar sail acceleration are strongly related. For this reason, once the characteristic acceleration has been fixed, it is not possible to modulate the acceleration in a particular direction. In this work, a semi-analytical switching control law is derived, enabling a solar sail to emulate a smaller effective characteristic acceleration (without changes in geometry or optical properties); by periodically changing the pitch (cone) angle of the sail, in average over time, the acceleration produced by the sail matches exactly (in both direction and magnitude) that of a “smaller” sail. The range in which this is possible is determined, and the limitations on this range due to the size difference is computed. The method is validated on optimal Earth-Mars trajectories. 相似文献
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Angelo Tartaglia Matteo Luca Ruggiero Emiliano Capolongo 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
We introduce an operational approach to the use of pulsating sources, located at spatial infinity, for defining a relativistic positioning and navigation system, based on the use of four-dimensional bases of null four-vectors, in flat spacetime. As a prototypical case, we show how pulsars can be used to define such a positioning system. The reception of the pulses for a set of different sources whose positions in the sky and periods are assumed to be known allows the determination of the user’s coordinates and spacetime trajectory, in the reference frame where the sources are at rest. We describe our approach in flat Minkowski spacetime, and discuss the validity of this and other approximations we have considered. 相似文献
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F. Dalla Vedova H. Henrion M. Leipold Th. Girot R. Vaudemont Th. Belmonte K. Fleury O. Le Couls 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
SSM (Solar Sail Materials) is an on-going project for the European Space Agency (ESA) relying on past and recent European solar sail design projects. It aims at developing and testing future technologies suitable for large, operational solar sailcrafts. 相似文献
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Lorenzo Borello Giuseppe Villero Matteo Dalla Vedova 《Aerospace Science and Technology》2009,13(8):475-487
The asymmetry limitation between left and right wing flap surfaces is one of the most severe requirements for the design of the actuation and control system. Each asymmetry exceeding a defined value must be detected and limited by appropriate monitoring devices equipped with a suitable software.In the design of a new flap control system the development of the asymmetry monitoring system plays a very important role and it is a very debated matter in industrial field. Nevertheless in scientific literature this topic is so neglected that, at the best of our knowledge, no paper dealing with the specific argument exists, except for the authors' works listed in the references.The currently used monitoring technique is based on the differential position control between left and right surfaces. Nevertheless in particularly severe conditions the above mentioned technique may be unable to prevent potentially critical asymmetries; in order to limit the above mentioned shortcomings, the authors proposed and developed some innovative monitoring techniques in previous papers. Their use generally reduces the asymmetry slightly, but in some cases it may have an unreliable behavior. In order to overcome the shortcomings of the previous models, in this work the authors develop and propose new different monitoring strategies and assess their positive effects on the maximum asymmetry following a torque tube failure. 相似文献
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Iain Moore Matteo Ceriotti 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(9):3027-3044
A major cause of spacecraft orbital variation comes from natural perturbations, which, in close proximity of a body, are dominated by its non-spherical nature. For small bodies, such as asteroids, these effects can be considerable, given their uneven (and uncertain) mass distribution. Solar sail technology is proposed to reduce or eliminate the net secular effects of the irregular gravity field on the orbit. Initially, a sensitivity analysis will be carried out on the system which will show high sensitivity to changes in initial conditions. This presents a challenge for optimisation methods which require an initial guess of the solution. As such, the Genetic Algorithm (GA) is proposed as the preferred optimisation method as this requires no initial guess from the user. A multi-objective optimisation is performed which aims to achieve a periodic orbit whilst also minimising the effort required by the sail to do so. Given the system sensitivity, the control law for one orbit is not necessarily applicable for any subsequent orbit. Therefore, a new method of updating the control law for subsequent orbits is presented, based on linearisation and use of a Control Transition Matrix (CTM). The techniques will later find application in a multiple asteroid rendezvous mission with a solar sail as the primary propulsion system. 相似文献
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Stefano Della Torre Pavol Bobik Matteo J. Boschini Cristina Consolandi Massimo Gervasi Davide Grandi Karel Kudela Simonetta Pensotti Pier Giorgio Rancoita Davide Rozza Mauro Tacconi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
We implemented a 2D Monte Carlo model to simulate the solar modulation of galactic cosmic rays. The model is based on the Parker’s transport equation which contains diffusion, convection, particle drift and energy loss. Following the evolution in time of the solar activity, we are able to modulate a local interstellar spectrum (LIS), that we assumed isotropic beyond the termination shock, down to the Earth position inside the heliosphere. In this work we focused our attention to the cosmic ray positron fraction at energy below ∼10 GeV, showing how the particle drift processes could explain different results for AMS-01 and PAMELA. We compare our modulated spectra with observations at Earth, and then make a prediction of the cosmic ray positron fraction for the AMS-02 experiment. 相似文献
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Matteo Ceriotti Giulia Viavattene Iain Moore Alessandro Peloni Colin R. McInnes Jan Thimo Grundmann 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(9):3012-3026
Near-Earth object (NEO) in-situ exploration can provide invaluable information for science, possible future deflection actions and resource utilisation. This is only possible with space missions which approach the asteroid from its vicinity, i.e. rendezvous. This paper explores the use of solar sailing as means of propulsion for NEO rendezvous missions. Given the current state of sail technology, we search for multiple rendezvous missions of up to ten years and characteristic acceleration of up to 0.10 mm/s2. Using a tree-search technique and subsequent trajectory optimisation, we find numerous options of up to three NEO encounters in the launch window 2019–2027. In addition, we explore steerable and throttleable low-thrust (e.g. solar-electric) rendezvous to a particular group of NEOs, the Taurid swarm. We show that an acceleration of 0.23 mm/s2 would suffice for a rendezvous in approximately 2000 days, while shorter transfers are available as the acceleration increases. Finally, we show low-thrust options (0.3 mm/s2) to the fictitious asteroid 2019 PDC, as part of an asteroid deflection exercise. 相似文献