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Darmstadt, Germany

Colombo C.,Polytechnic of Milan | Alessi E.M.,CNR Institute of Applied Physics Nello Carrara | Weg W.V.D.,University of Strathclyde | Soldini S.,University of Southampton | And 5 more authors.
Acta Astronautica

Libration Point Orbits (LPOs) and Highly Elliptical Orbits (HEOs) are often selected for astrophysics and solar terrestrial missions. No guidelines currently exist for their end-of-life disposal. However, as current and future missions are planned to be placed on these orbits, it is a critical aspect to clear these regions at the end of operations to avoid damage to other spacecraft and ensure on-ground safety. This paper presents an analysis of possible disposal strategies for LPO and HEO missions as a result of a European Space Agency study. The dynamical models and the design approach are presented for each disposal option. Five current missions are selected as test cases Herschel, Gaia, SOHO as LPOs, and INTEGRAL and XMM-Newton as HEOs. A trade-off on the disposal options is made considering technical feasibility, as well as the sustainability context. © 2015 IAA. Published by Elsevier Ltd. All rights reserved. Source

Dow R.M.,ESA ESOC | Argamasilla R.C.,Terma GmbH
62nd International Astronautical Congress 2011, IAC 2011

The implementation of a knowledge management system is not a straight forward project although many procedures and recommendations have been published during the past decade. The approach taken within this paper is based on a comparison of barriers and instruments. In fact, the number of barriers is very high and the scope is very wide. For illustration only some of these examples are quoted here. They are: knowledge as a personal possession, error-free instead of error-tolerated culture, rigid organizational structures and no common data structures. On the other hand the number of instruments is also very high and the scope is also very wide. For illustration some of these examples are listed. These can be: teamwork, knowledge markets, communities of practice, networks, knowledge maps, yellow and blue pages, lessons learned, best practice workshops, appropriate documentation, intelligent search, E-learning. The list of examples can easily be extended. The analysis reviews the relevant barriers, their overcoming and the applicability of the knowledge management instruments. The comparison requires a grouping for all these items. The grouping uses the well-known structure of people, leadership, organization and IT. For each of the breakdown elements relations between the sets of barriers and instruments are established so that for a given company environment with its barriers the appropriate set of instruments can be selected. The paper concludes with a proposed sequence of steps for the implementation of a knowledge management system. Copyright © 2011 by the American Institute Federation of Aeronautics and Astronautics, Inc. All rights reserved. Source

Milani A.,University of Pisa | Tommei G.,University of Pisa | Farnocchia D.,University of Pisa | Rossi A.,CNR Institute of Applied Physics Nello Carrara | And 2 more authors.
Monthly Notices of the Royal Astronomical Society

While building up a catalogue of Earth-orbiting objects, the available optical observations are typically sparse. In this case, no orbit determination is possible without previous correlation of observations obtained at different times. This correlation step is the most computationally intensive, and becomes more and more difficult as the number of objects to be discovered increases. In this paper, we tested two different algorithms, and the related prototype software, recently developed to solve the correlation problem for objects in geostationary orbit (GEO). The algorithms allow the accurate orbit determination by full least-squares solutions with all six orbital elements. The presence of a significant subpopulation of high area-to-mass ratio objects in the GEO region, strongly affected by non-gravitational perturbations, required to solve also for dynamical parameters describing these effects, that is to fit between six and eight free parameters for each orbit. The validation was based upon a set of real data, acquired from the European Space Agency (ESA) Space Debris Telescope (ESASDT) at the Teide Observatory (Canary Islands). We proved that it is possible to assemble a set of sparse observations into a set of objects with orbits. This would allow a survey strategy covering the region of interest in the sky just once per night. As a result, it would be possible to significantly reduce the requirements for a future telescope network, with respect to what would have been required with the previously known algorithms for correlation and orbit determination. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS. Source

Navarro V.,ESA ESOC | James S.,Logica
SpaceOps 2010 Conference

The Mission Control System infrastructure at ESOC supports the storage of mission operations data in dedicated archives designed to manage specific types of data, namely Packets, Parameters and Files1. Generic user applications support the retrieval and visualization of these data, but do not provide the powerful post-processing or querying needed between heterogeneous data samples (e.g. commands, events, monitoring parameters or configuration variables). This represents a significant deficiency of the mission data systems, as there is an increasing demand for a powerful off-line environment where operational data can be further analysed. The Analysis and Reporting System (ARES) is the cost effective solution developed by ESA to meet this operational need. © 2010 by European Space Agency. Published by the American Institute of Aeronautics and Astronautics, Inc. Source

Escoubet C.P.,European Space Agency | T. Taylor M.G.G.,European Space Agency | Masson A.,European Space Agency | Laakso H.,European Space Agency | And 3 more authors.
Annales Geophysicae

After 12 years of operations, the Cluster mission continues to successfully fulfil its scientific objectives. The main goal of the Cluster mission, comprised of four identical spacecraft, is to study in three dimensions small-scale plasma structures in key plasma regions of the Earth's environment: solar wind and bow shock, magnetopause, polar cusps, magnetotail, plasmasphere and auroral zone. During the course of the mission, the relative distance between the four spacecraft has been varied from 20 km to 36 000 km to study the scientific regions of interest at different scales. Since summer 2005, new multi-scale constellations have been implemented, wherein three spacecraft (C1, C2, C3) are separated by 10 000 km, while the fourth one (C4) is at a variable distance ranging between 20 km and 10 000 km from C3. Recent observations were conducted in the auroral acceleration region with the spacecraft separated by 1000s km. We present highlights of the results obtained during the last 12 years on collisionless shocks, magnetopause waves, magnetotail dynamics, plasmaspheric structures, and the auroral acceleration region. In addition, we highlight Cluster results on understanding the impact of Coronal Mass Ejections (CME) on the Earth environment. We will also present Cluster data accessibility through the Cluster Science Data System (CSDS), and the Cluster Active Archive (CAA), which was implemented to provide a permanent and public archive of high resolution Cluster data from all instruments. © Author(s) 2013. Source

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