Teaching Planetary Defence by means of role-playing games

Introduction

The effectiveness of game-based learning methods [1] in facilitating understanding of complex concepts, arousing the interest of students and encouraging memorization is widely recognized [2], especially in the field of STEM subjects [3]. In particular, role-playing games entail a deep involvement of the student in the scenario that is presented and allow to experience issues from a unique perspective. Given this quality of role-playing games, we propose their use as a means for scientific dissemination of the concepts underlying Planetary Defense, i.e. the methods for the protection of the Earth from asteroids on a collision course with our planet. Particular importance is attributed to the process of Orbit Determination, in which the Celestial Mechanics Group of the Department of Mathematics of the University of Pisa plays a significant role.

Methodology

The project consists of three phases:

Phase 1

A series of lectures aimed at describing the status of Planetary Defence and providing insights about the various steps that follow the discovery of an asteroid.

The following topics are covered:

• Minor bodies of the solar system: location and categories (with a focus on asteroids and Near-Earth Objects), Yarkovsky and YORP effects, observational techniques, discovery and nomenclature of asteroids, centers involved with Planetary Defence;
• Orbit determination: observations and uncertainties, parameter estimation, impact corridor, probability of impact, monitoring systems;
• Impact and mitigation: effects of an asteroid impact, Torino scale, space missions and deflection methods, example of the DART and Hera missions.

Phase 2

Simulation of the discovery of a potentially dangerous asteroid, conducted in the form of a role-playing session that allows students to identify with the main players in Planetary Defence and put into practice the notions acquired in Phase 1.

The simulation is inspired by the "2024 Interagency Tabletop Exercise" sponsored by the NASA Planetary Defense Coordination Office (PDCO) and the Federal Emergency Management Agency (FEMA), which we adapted for an audience of high school students.

The participants are divided into three groups, each representing one of the actors in the Planetary Defence framework: Astronomers, Mathematicians and Engineers. The groups are then confronted with the hypothetical scenario, set in 2023, of the discovery of an asteroid with a small probability of impacting the Earth in the following 15 years.

The simulation is structured as follows:

• Description of the initial scenario: as of 4/10/2023 the Astronomers receive three images of the night sky, in which an asteroid is present. Using the techniques seen in Phase 1, Astronomers must identify the asteroid and try to estimate its apparent magnitude and indicate to which centres it is appropriate to communicate the results.
• Confirmation of discovery: the next day, 5/10/2023, the Minor Planet Center confirms the discovery of the observed object, reporting that the impact monitoring systems computed a 0.01% impact probability. Astronomers are therefore asked to assign a name to the object and establish an observational plan to continue monitoring it.
• Preliminary orbit calculation: Mathematicians are required to use the CNEOS Orbit Viewer (https://cneos.jpl.nasa.gov/orbits/custom/ttx24.html) to visualize the object's orbit, find the dates of close encounters with the Earth and, among these, identify the date of possible impact.
• Communication with the media: through the analysis of new observations and of archival data, the probability of impact is continuously updated and gradually rises to reach 10% by 31/03/2024. Starting from this date, the asteroid will not be observable for seven months. The alert thresholds that make it advisable to develop Planetary Defense missions have been crossed. The three groups are asked to discuss together on the possible strategies to be implemented and, in particular, to establish whether it is necessary to implement one or more reconnaissance and/or mitigation missions. Through fake newspaper headings and posts, the media reaction to the news of the discovery of a dangerous asteroid is shown. The three groups are jointly invited to issue a statement to the media to prevent panic from spreading and limit the impact of fake news.
• Mission Plans: Orbit Engineers and Mathematicians are required to use the NEO Deflection App (https://cneos.jpl.nasa.gov/nda/), made available by CNEOS, to assess the feasibility of a deflection mission and to calculate the timing and costs. Astronomers are required to select the scientific instruments necessary to achieve the purpose of the designed missions.
• Final decisions: the probability of impact rises to 72% and it is estimated that the diameter of the object is between 60 and 800 m. All groups assess the potential damage caused by the impact and establish a definitive course of action. This can be provided for (without being limited to) the implementation of one or more reconnaissance missions, mitigation, ground countermeasures (e.g. evacuation of the population from the impact corridor and provide humanitarian aid for the affected areas), observation plans with instruments not yet used, etc.
• Result: based on the choices made, a score is assigned (unique for all students) between 1 and 19, obtained subtracting one point from the maximum value for each choice that has led to the increase of the uncertainties involved (e.g. attempting the deflection without first determining the mass of the asteroid). The moderator extracts a number between 1 and 20: if this number is less than or equal to the score obtained by the students, the mitigation plan is successful, and the impact is avoided. Otherwise, the impact happens, and students take measures to contain the damage.

Phase 3

A constructive discussion about the results of the simulation and a critical analysis of the choices made during Phase 2. The moderator retraces the various stages of the simulation, highlighting the consequences of the choices made and proposing, when appropriate, ideas for alternative courses of action and clarifying any doubts of the students. At this stage, a strong emphasis is placed on the importance of international collaboration.

The students are then presented with a feedback form, that is used to evaluate the impact of the simulation on their understanding of Planetary Defence.

Bibliography

[1] Hanghøj T., 2013, New Pedagogical Approaches in Game Enhanced Learning: Curriculum Integration, [2] Terracina A., Berta R., Bordini F., Damilano R., Mecella M., 2016, 2016 IEEE 16th International Conference on Advanced Learning Technologies, [3] Randi M., Carvalho H., 2013, Brazilian Journal of Medical Education 37.