Speakers
Description
The growing interest in addressing asteroid threat scenarios is justified by current estimates of the Potentially Hazardous Objects (PHOs) population and by recent impacts on Earth. Since 2015, exercises involving hypothetical hazardous asteroids have been proposed, with various solutions discussed during Planetary Defense Conferences (PDCs). This paper presents and analyses preliminary mission design options for the mitigation of asteroid “2024 PDC25”, focus of the scenario introduced for the PDC 2025. To significantly enhance the knowledge of the asteroid’s properties and inform the design of deflection campaigns, impulsive fast fly-by and low-thrust rendezvous reconnaissance mission options are developed. The Single and Multiple Kinetic Impactor (KI) deviation strategies are analysed, leveraging the results from the DART mission. Uncertainties in various parameters are subsequently incorporated into the developed model. Among all elements, the variation of the momentum enhancement factor on the resulting deflection, after one or more impacts, strongly influences the variability of other aspects involved in the physical problem. Based on this analysis, a set of successful and unsuccessful missions are identified. A successful mission would imply the ability to modify the trajectory of the asteroid, while preventing its fragmentation, but it may not guarantee a deviation of at least two Earth radii. Although the KI is the only flight-proven deflection strategy, it does not always represent the most suitable option. Based on the provided estimates of the asteroid size and mass, different percentile cases are identified. For percentile levels associated with particularly small or large masses, neither the KI nor the Multiple KI are capable of fully deviating the asteroid. Other strategies with a lower Technology Readiness Level (TRL) proved to be more effective for a wider range of percentile cases. Nuclear Explosive Devices (NEDs) provide the highest energy density among all deflection techniques, making them a viable impulsive alternative to Kinetic Impactors. A model is developed for Single and Multiple NEDs in a "Carrier" configuration, which offers redundancy and divides the total ∆𝒗 into smaller, controlled impulses to prevent asteroid fragmentation. Specifically, each impulse is kept below a small percentage of the asteroid's surface escape velocity. Given the sufficiently large warning time available, models of slow push/pull deflection strategies are developed and applied to this specific scenario. A preliminary design of deflection missions is therefore proposed for Single Standard, Enhanced and Multiple Gravity Tractor, Single and Multiple Laser Ablation, Single Ion Beam Deflection (IBD) and a newly developed technique of Multiple IBD in Formation Flying. The results are compared, and the most effective deviation strategies for asteroid “2024 PDC25” are discussed.