ACT - Ariadna

Politecnico di Milano.
Glasgow University.
Observatoire de la Côte d'Azur and University of Nice-Sophia Antipolis.

Near Earth Objects (NEOs) come closer to us than any other bodies in the solar system yet despite this, we still know relatively little about options to tackle the threat that they represent.

In 2029 the several-hundred-meter diameter asteroid 99942 Apophis (2004 MN4) will flyby the Earth at a distance of about 32 000 km. This is closer than any known past or future approach by natural objects larger than about 10 meters (other than objects that have entered Earth's atmosphere). After a resonant flyby, the asteroid will then return towards Earth with two potential impact dates between 2036 and 2037.

The terrestrial impact threat posed by NEOs is widely known but there are still no plans in place to ensure that we will be technologically ready to cope with such a threat should it occur. Similarly, clear R&D guidelines to follow in the event that a NEO were predicted to have unacceptably high impact risk are also lacking.

The public awareness of the threat posed by NEOs is high due to the general interest of their role within our Solar System, the important part they may have played in the evolution of life on Earth, and also due to the remarkable attention given to the subject in popular culture e.g. films and sci-fi literature. There are already questions surrounding Europe's ability to deal with the NEO hazard ([7]-[10]) and by 2029, when it will be fully realised by the large public, ESA and Europe will be expected to have developed an official policy and a technical mitigation capacity.

Although it is known that Apophis will very likely not impact Earth on any of these dates, and while no NEO impact disastrous to society has occurred yet, the close encounter with Apophis in 2029 will provide a window of opportunity for scientific and technological research and for educating the public and decision makers on the nature of this recognized problem.

Moreover, as new, more powerful NEO survey programmes become operational in the coming years, it is reasonable to expect more Apophis-like events to be discovered and reported. This will pose new challenges, not only from the risk assessment and the risk communication point of view but also in ensuring that the near-Earth encounters are going to be used efficiently to increase our knowledge of the NEO population.

The main aim of this Call for Ideas is to attract proposals for new and innovative scientific and technical studies, which will act as the first steps towards increasing our knowledge and level of preparation for the initiation of a NEO hazard mitigation response. Several study proposals will be accepted and these will lead to parallel medium term (4 month) research studies carried out in collaboration with ESA.

Although mitigation and deflection options and requirements will be the primary focus of the studies, proposals will be welcomed from all fields of NEO research (e.g. innovative methods for detection and characterisation, impact effects, dynamics and simulations) and other fields of scientific and technical research provided the importance and benefit of the study can be justified with reference to:

This Call for Ideas intends to focus on working together with members of the academic community with the goal to first define a step-by-step approach of the underlying research needed to effectively tackle Apophis-class asteroid impacts, and then subsequently to perform the first research steps in the proposed approach. The close fly-by of Apophis will be considered as a representative reference scenario.

The scientific and technical content of the study proposal will be of great importance but in addition particular emphasis shall be put on the logical integration and credibility of the proposed study as a first research step in a roadmap of required events and steps.

Therefore, as part of the proposal, researchers are expected to provide a consistent roadmap within their field of expertise, including brief descriptions of the underlying logic, the key steps and approximate timeline over the next two decades specifically for dealing with Apophis-class objects (in terms of size but not necessarily in terms of orbital characteristics or expected physical properties).

The proposed milestones contained within the timeline are expected to represent credible solutions, possible to achieve with the right amount of research, funding and direction. A generic roadmap is not expected, as ESA will eventually assemble all of the individual, specific roadmaps into on overall map integrating many fields of expertise. Instead the timeline should be specifically tailored to the researchers' expertise and should demonstrate the suitability of the proposed research study to act as a first building block within the proposed roadmap.

This roadmap should include:

All findings and predictions are to be based on sound scientific and technological knowledge and realistic predictions. Proposers are encouraged to underline their reasoning with references to published papers and research results. The proposed Call for Ideas research studies should be feasible and constitute an important first step towards reaching the goals, as defined in the proposers' roadmap, by 2029. The study can lead directly to progress in the proposers' area(s) of expertise or alternatively provide a valuable, valid contribution towards achieving targets in another field of NEO research and technology. Unpublished, innovative ideas and concepts are strongly encouraged and will be regarded positively.

[1] D'Arrigo, P. and Santandrea, S., The APIES Mission, Advances in Space Research, Vol. 38, N. 9, pp. 2060-2067, 2006

[2] Clark P.E., Curtis S.A. , and Rilee M.L., ANTS: Applying a New Paradigm for Lunar and Planetary Exploration, Proceedings of the Solar System Remote Sensing Symposium, pp.15+, 2002

[3] Bonabeau E., Dorigo M. and Theraulaz G, Swarm Intelligence From Natural to Artificial Systems, Oxford University Press, 1999

[4] Dorigo, M., Trianni, V., Sahin, E., Labella, T.H., Gross, R., Baldassarre, G., Nolfi, S., Mondada, F., Deneubourg, J.-L., Floreano, D. and Gambardella, L.M., Evolving Self- Organizing Behaviors for a Swarm-bot. Autonomous Robots, Vol. 17, N. 2-3, pp. 223-245, 2004

[5] Izzo, D., Pettazzi, L., Autonomous and Distributed motion planning for satellite swarm, to appear in Journal of Guidance Control and Dynamics, 2007

[6] Izzo, D., Pettazzi, L., Girimonte, D. (2007) Swarm Intelligence For Orbital Control Applications, Workshop on Artificial Intelligence for Space Applications at 20th International Joint Conference on Artificial Intelligence (IJCAI), Hyderabad, India, 2007

[7] The Council of Europe (Resolution 1080 of 26 March 1996 on the detection of asteroids and comets potentially dangerous to humankind)

[8] Report of the [UK] Task Force on Potentially Hazardous Near-Earth Objects, September 2000 Recommendation 6

[9] The Report of the 3rd United Nations Conference on the Exploration and Peaceful Uses of Outer Space (Declaration of Vienna)

[10] OECD Global Science Forum Workshop on NEOs: Risks, Policies and Actions, 20-22 January, 2003

[11] Bombardelli, C., Nonexplosive Approach to Fragment Subkilometer Asteroids with a Tether Centrifuge, Journal of Guidance Control and Dynamics, 30(5), pp.1546-1550, 2007.

[12] Izzo, D., Optimization of Interplanetary Trajectories for Impulsive and Continuous Asteroid Deflection, Journal of Guidance Control and Dynamics, 30(2), pp.401-408, 2007.

[13] Izzo, D., Vinko, T., Bombardelli, C., Brendelberger, S., and Centuori, S., Automated Asteroid Selection for a Grand Tour Mission, Paper IAC-07-C1.7.07, 58th International Astronautical Congress, Hyderabad, India, 2007.

[14] Izzo, D. and Rathke, A., The asteroid deflection formula for Earth quasi co-orbiting asteroids, European Space Agency, the Advanced Concepts Team, ACT technical report (ADFECA06), 2006.

[15] Rathke, A. and Izzo, D., Keplerian Consequences of an impact on an asteroid and their relevance for a deflection demonstration mission, Near Earth Objects, our Celestial neighbours: Opportunity and Risk, proceedings IAU symposium No.236, 2006.

[16] Carnelli, I., Gálvez, A., and Ongaro, F., Learning to Deflect Near-Earth Objects: Industrial Design of the Don Quijote mission, Paper IAC-06-A3.5.5, 57th International Astronautical Congress, Valencia, Spain, 2006.

[17] Carnelli, I. and Gálvez, A., ESA's Don Quijote Mission: an Opportunity for the Investigation of an Articial Impact Crater on an Asteroid, Paper ISTS 2006-k-26, 25th International Symposium on Space Technology and Science, Kanazawa, Japan, 2006.

[18] Gálvez, A. and Carnelli, I., ESA Studies on the Don Quijote NEO mission: dealing with impact uncertainties, Paper IAC-05-Q.P.21, 56th International Astronautical Congress, Fukuoka, Japan, 2005.

[19] Gálvez, A., Coradini, M., and Ongaro, F., The Role of Space Missions in the Assessment of the NEO Impact Hazard, IAC 2003, Bremen, Germany, 2003.

[20] Vasile, M., Robust Optimisation of Trajectories Intercepting Dangerous NEO, AIAA-2002-4719 AIAA/AAS Astrodynamic Specialist Conference, Monterey, California, 2002

The following ESA documents and webpages are completed General Studies Programme contracts containing information related to NEOs:

[21] "Study of a global network for research on Near-Earth Objects", contractor: Spaceguard Fopundation, 1997 (http://www.esa.int/SPECIALS/GSP/SEM32LZO4HD_0.html)

[22] "NEO-MIPA - Near-Earth Object - Hazard Mitigation Publication Analysis", contractor: EUROSPACE / TU Dresden, 2001 (http://www.tu-dresden.de/mw/ilr/space/rfs/Dokumente/Publikationen/NEO-MIPA-report.pdf)

[23] "Understanding the distribution of Near Earth Objects", contractor: Univ. Genova(I), 2000 (http://www.esa.int/SPECIALS/GSP/SEMDN8ZO4HD_0.html)

[24] "Spaceguard Integrated System for Potentially Hazardous Object Survey", contractor: Spaceguard Foundation, 1998 (http://www.esa.int/SPECIALS/GSP/SEM6XKZO4HD_0.html)

[25] “Study on NEO Hazard and Options for Mitigation”, contractor: Eurospace (D) (http://www.esa.int/SPECIALS/GSP/SEM1AEZO4HD_0.html)

[26] Balogh, A et al, Asteroid Exploration Mission (ASTEREX) Assessment study, 1979

[27] Kubota, T., Navigation, guidance and control of asteroid sample return spacecraft: MUSES-C, 1999