HAO Colloquium - Charles Bussy-Virat, University of Michigan

Predicting Space Weather Forecast Errors and their Effects on Spacecraft Collision Avoidance

When an extreme solar event occurs, it can significantly increase the neutral density in the upper atmosphere. The enhancement in neutral density results in an increase in atmospheric drag acting on satellites in low Earth orbit (below ~1,000 km), which dramatically alters their trajectories. Such hardly forecastable trajectory perturbations represent serious threats as they prevent mission operators from accurately predicting collisions in space, and as such, from planning mitigation procedures. A high accuracy algorithm, called the Spacecraft Orbital Characterization Kit (SpOCK), has been developed to predict the effects of solar activity forecast errors on the probability of collision between objects in space. The presentation shows examples of application of the SpOCK model in order to put in evidence the effects of space weather forecasting errors on the probability of collision. The study also demonstrates the importance of modeling errors in the forecast of the solar activity during the collision risk assessment process. Instead of predicting a single scenario for a given solar wind parameter, such as the solar wind speed, providing an ensemble of predictions allows for a more robust assessment of the risk of collision. The Probability Distribution Function (PDF) model was developed to generate ensemble prediction scenarios for the solar wind speed and assign an uncertainty on the prediction. The methodology and examples of applications of the PDF model are presented as well.

Date and time: 
Wednesday, February 27, 2019 - 2:00pm to 3:00pm