Addressing imminent impactors threat from distant retrograde orbits (DRO)

Planetary Defence is gaining momentum after the launching toward the Didymos binary system of NASA DART, the first asteroid deflection mission, foreseeing also the deployment of ASI’s LICIAcube. Moreover, the ESA Hera spacecraft, which will contribute to assessing the DART impact momentum transfer, is in full realization phase. After the well established US planetary defence activities, the European Union has recently included the NEO hazard in its own Space Programme in order to extend and complement the ESA initiatives i.e. the establishment of NEO Coordination centre at ESRIN and the realization of the wide-field high-sensitivity Flyeye telescope. Both NASA and ESA also plan to improve the efficiency of their observational networks by launching space mission devoted to NEO observations from space. Finally, the ever-growing NEO discovery rate moves toward increasingly smaller objects passing close to our planet, thus posing new challenges in performing follow- up observations for determining their orbital and physical properties. Within this framework, addressing the so called ”imminent impactors” threat, posed by objects in the 10-40 m range in route of collision with the Earth (the Tunguska-class objects), has become a key issue for planetary defence. Deflection capabilities are useless if a celestial body large enough to produce significant damage can sneak up on the Earth undetected, as could asteroids hiding by the Sun, lurking in the well-known blind spot that ground-based observations can never peer into. In this respect the advantages of placing a telescope on a stable Distant Retrograde Obit (DRO) around the Earth when compared with other orbital configurations have already been proven, and they are now well established in the literature. In this work the feasibility of a mission scenario foreseeing a constellation of four spacecraft in DRO is invesitgated in detail, comparing several target orbits and different transfer strategies, including lunar swing-bys. The more efficient orbital configurations in terms of accessibility and detection capabilities are investigated and validated using case studies of historic asteroid undetected close encounters. Results prove that a DRO constellation would be able to detect and refine the trajectory of a Tunguska-size object with a warning time exceeding the requirement set for natural disasters. The possibility of contributing to the physical characterization of an imminent impactor is also discussed, which is essential for building up an efficient rapid response system for civil protection purposes.European Union funding: 87040

The observing campaign on the deep-space debris WT1190F as a test case for short-warning NEO impacts

On 2015 November 13, the small artificial object designated WT1190F entered the Earth atmosphere above the Indian Ocean offshore Sri Lanka after being discovered as a possible new asteroid only a few weeks earlier. At ESA's SSA-NEO Coordination Centre we took advantage of this opportunity to organize a ground-based observational campaign, using WT1190F as a test case for a possible similar future event involving a natural asteroidal body. <P /

Celestial mechanics: the waltz of the planets

The aim of this book is to demonstrate to a wider audience, as well as to a more skilled audience, the many fascinating aspects of modern celestial mechanics. It sets out to do this without the use of mathematics

Space Manifold Dynamics: Novel Spaceways for Science and Exploration /

This book presents an overview of the outcomes resulting from applying the dynamical systems approach to space mission design, a topic referred to as "Space Manifold Dynamics" (SMD). It is a natural follow-on to the international workshop "Novel Spaceways for Scientific and Exploration Missions," which was held in October 2007 at the Telespazio Fucino Space Centre (Italy) under the auspices of the Space OPS Academy. The benefits and drawbacks of using the Lagrangian points and the associated trajectories for present and future space missions are discussed. The related methods and algorithms are also described in detail. Each topic is presented in articles that were written as far as possible to be self consistent; the use of introductory sections and of extended explanations is included in order to address the different communities potentially interested in SMD: space science, the aerospace industry, manned and unmanned exploration, celestial mechanics, and flight dynamics

Cosmic visions in Celestial Mechanics

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The SSA NEO Segment and Gaia: Present Opportunities and Future Developments

International audienceOne of the major elements of the ESA Space Situational Awareness (SSA) programme is devoted to NEO hazard monitoring through the set-up and the operation of a dedicated data centre [1]. This implies the availability of advanced systems for orbit computation and impact monitoring, the possibility to store and retrieve all relevant data (orbital parameters, physical properties, raw image archives etc) and the coordination of NEO observations for discovery and follow-up. Thus the aim of the SSA NEO Segment is to become a worldwide reference for potential SSA customers and stakeholders such as the scientific community, governmental institutions, insurance companies and the public at large. The NEO Segment is presently in the Precursor Services phase and the deoployment of a NEO Data Centre at ESRIN (Frascati, Italy) has been successfully achieved

Study for potential candidates for a Sample Return Spase Mission to a Near Earth Object .

International audienc