IAC-04-Q.P.21 Don Quijote: An ESA mission for the assessment of the NEO threat José A. González1, Miguel Belló1, Juan F. Martín-Albo1, Andrés Gálvez2 1DEIMOS Space S.L., Ronda de Poniente, 19, Ed. FITENI VI, Portal 2, 2º 28760 Tres Cantos, Spain. Phone: +34 91 8063450, Fax: +34 91 8063451 2Advanced Concepts Team, ESA – ESTEC, Keplerlaan 1, 2200 AZ, Noordwijk ZH, The Netherlands. Phone: +31 71 5653118, Fax: +31 71 5656024 [email protected], [email protected], [email protected], [email protected] ABSTRACT There is overwhelming scientific evidence that impacts Near-Earth Objects (NEOs) could trigger a catastrophe that might have consequences at a global scale. In July 2002 the General Studies Programme of the European Space Agency (ESA) provided funding for preliminary studies of six space missions that could make significant contributions to our knowledge of the NEOs and the threat the represent to life on Earth. This was the first time ever that the full range of NEO space systems were explored and assessed in detail within the scope of a single activity. Following the completion and presentation of these studies, the ESA Near-Earth Object Mission Advisory Panel (NEOMAP) was established in January 2004. NEOMAP was charged with the task of advising ESA on the most effective options for ESA participation in a space mission to contribute to the assessment of the NEO impact hazard and pave the way for the definition of effective impact mitigation strat egies. This paper summarizes the final recommendations of the panel and provides an overview of the selected concept, the Don Quijote space mission. INTRODUCTION on several studies and internal assessments that are enabling to elaborate a coherent roadmap of Near Earth Objects, or NEOs, are not simply a European NEO risk assessment space systems. scientific curiosity. In practical terms, if colliding with the Earth, they may originate one of the worst possible natural disasters. There is now overwhelming evidence that large impacts -of objects As the further step towards this goal, in January 2004 ESA established a NEO Mission Advisory Panel with dimensions in the order of kilometres- have had catastrophic consequences in the past, in spite of (NEOMAP), having the objective to discuss the results of the NEO mission feasibility studies carried being also extremely infrequent. Objects of various sizes can cause significant damage when they hit the out in the frame of the “NEO Space Mission Preparation” activity and make recommendations on Earth at random intervals of hundreds or thousands of years. the next actions to be undertaken by ESA. The NEOMAP is composed by recognised European The magnitude of the problem has been recognised in experts on various aspects on the NEOs (detection, many occasions. The resolution 1080 Council of orbit determination, physical characterisation) and Europe has provided recommendations on this issue on the impact threat they pose to our planet. [1] and a task force on the subject was established in the UK [2]. The importance of international This paper describes the recommendation resulting from their work and describes the prospects of initiatives to further our understanding on the NEO has also been highlighted in other international establishing a cooperative project for the forums at the highest level such as the UN COPUOS development of a space mission using the selected “Don Quijote” concept as a reference mission. [3] and the OECD Global Science Forum [4]. Nevertheless the current level of activity in the area THE ROLE OF SPACE MISSIONS FOR THE of NEO impact risk assessment, both in Europe and ASSESSMENT OF THE NEO HAZARD worldwide, is only large among academicians but Up to now, most European efforts on NEOs have still very limited at institutional level. concentrated in the theoretical modelling of the NEO The European Space Agency’s long-term space policy population, coordination and improvement of ground- [5] identified NEO research as a task that should be based survey programmes, distribution and analysis actively pursued by the Agency. ESA has as a of astrometric data, NEO orbit determination, consequence decided to follow a stepwise approach, (remote) physical characterisation, and modelling of assessing European interests and capabilities, and their physical properties. Some of these activities are defining a strategy at a European level first as a supported directly by ESA; as a matter of fact the preparatory step for a framework of international Spaceguard Central Node (SCN) is hosted by ESA at cooperation to be established. This approach is based - 1 - ESRIN and is advising ESA in all issues related to · In-situ characterisation missions These the NEOs. missions seek precise mass, volume, and internal structure determination, among Studies commissioned by ESA to date [6, 7, 8] other physical properties of the objects. indicate that a large potential also exists for the Space borne instruments are clearly the best utilisation of dedicated space-based assets to further and often only option to obtain these data, our understanding of the NEO hazard. Thanks to which are essential for the assessment of the these studies Europe as gained a good understanding consequences of an impact and the of the different existing options. countermeasures that can be adopted to These have also indicated that a phased approach is prevent it. The rendezvous mission concepts necessary so as to assess the threat, a prerequisite that were assessed in the NEO SMP activity for the development of effective mitigation were SIMONE [13], ISHTAR [14] and Don techniques. As a result of these considerations, the Quijote [15]. “Near Earth Objects Space Mission Preparation” · Finally, a subset of the second category, the (NEO SMP) parallel pre-phase A mission studies “NEO Precursor missions” was also defined. were conducted in the context of ESA´s General In addition to gathering data on the physical Studies Programme with a total budget of 900 KEUR properties of the objects, these missions would test deflection techniques leading to The studies represented an assessment of six the demonstration of the ability to move an different space mission concepts, all of them asteroid. Precursor missions have been dedicated to gather information on several aspects on identified as having a very high interest, the NEO hazard so that the most effective both from the NEO characterization and the countermeasures could be identified. All proposals technological point of view. assumed a financial mission envelope not exceeding All the missions considered in the “Near Earth that of a ESA Science programme “flexi” mission i.e. 150 MEUR in 1996 economic conditions. These Objects Space Mission Preparation” activity studies have been reviewed elsewhere and will not be represent interesting options and having an overview described here in detail [9]. of all them is necessary. Nevertheless, in practical terms it is not realistic to think that all of them will be implemented and some priorities should be Two broad types of space missions were addressed in the activity: defined. · Survey –type NEO missions. These are NEOMAP tasks and objectives missions dedicated to the detection, tracking ESA has been supported in the complex task of (i.e. orbit determination) and remote establishing priorities by an independent group of characterisation (e.g. determination of experts. The NEO Mission Advisory Panel taxonomic type and surface albedo). The main objective of these missions is to (NEOMAP) has provided the Agency with improve and expand our catalogue of recommendations on which project should be dangerous objects. Though space borne implemented first in the current context. The telescopes cannot be made as large and NEOMAP tasks were the following: powerful as their terrestrial counterparts, § Identify advantages and define a solid for these tasks and as a consequence of rationale of the utilisation of space missions improved viewing geometry and observation for the assessment of the NEO impact conditions the space option enables an hazard. It is not the objective of this task to improved access to certain types of objects. repeat previous work but to provide a brief These include Inner to Earth Objects (IEOs) and Atens, that due to their proximity to the summary of their main conclusions. Sun in the sky are often difficult to observe. § Identify which of those advantages These favourable conditions lead to efficient associated with the utilisation of space and extensive surveys in which smaller systems can complement ground-based objects down to a few hundred meters in size observation and data. This work will also be may also be detected and observed. In a summary and update of previous relevant addition to this, from space it is also possible studies. to have access to a broader range of § Revise and update the scientific priorities wavelengths (e.g. IR) and an improved duty for NEO hazard assessment mission cycle than from the ground. concepts entirely in terms of its value in The mission concepts in this category include EuNEOS [10], Earthguard-1 [11] reducing the risk of impact of a NEO - and and NERO [12] not e.g. by the value of the results to pure science. - 2 - § Judge the value of each mission concept and this knowledge gap in addition to providing valuable the potential benefits resulting from the information on the physical properties of the target implementation of the missions, considering object. Therefore, the Panel made the them in the context of current or future recommendation to ESA to given the highest priority international initiatives, either ground to this concept and use it as a basis for ESA’s surveys or other planned space missions. participation in a NEO impact-risk assessment and § Produce a set of prioritised reduction project. recommendations for both each mission DON QUIJOTE MISSION category (surveys and rendez-vous) and a proposal for (a) space mission(s) cooperative The Don Quijote study, leaded by DEIMOS Space, project(s) at international level.