PhD Proposal by Ulises Eduardo Núñez Garzón

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Ulises Eduardo Núñez Garzón
(Advisor: Prof. E. Glenn Lightsey]

will propose a doctoral thesis entitled,

On the Management of Collision Risk in Spacecraft Formations


Friday, April 15 at 3:00 p.m. EDT
Montgomery Knight Building 317

[Virtual address: https://gatech.zoom.us/j/93495553511?pwd=QVpNTVBKay8wN1BFaWVGQU1IeHo3Zz…]


This proposal presentation will provide an overview of the benefits of spacecraft formation flying (SFF), of the sources of collision risk in SFF, and a discussion on how relative orbital dynamics make the problem of collision risk management in SFF different from the standard obstacle avoidance problem in robotics. Contributions toward spacecraft formation risk management from this investigation are discussed in terms of collision risk quantification, interpretation and decision making, and reduction. First, a sampling method is developed for computation of probability measures in a space of prior initial conditions, with the goal of computing instantaneous and joint-time collision probabilities in spacecraft formation flying with comparable performance to Monte Carlo. Second, a methodology is developed for examining the consistency between collision risk insights that may be gleaned from distance-based and probability-based collision risk indicators, with recommendations for certain distance-based collision risk indicators whose relationship to collision probability is in accordance with intuition. Third, motivated by results on the relationship between instantaneous collision risk defined via planar projections and three-dimensional regions, incipient work is in progress to define a set of collision-safe nonconvex nonlinear constraints (in three-dimensional relative position space) in terms of geometric parameterizations of bounded, periodic relative orbits. The goal is to apply these safe sets in a guidance environment for collision avoidance via convexification of constraints and drift counteraction. Together, these contributions to an integrated approach to collision risk management constitute progress toward the goal of practical implementations of spacecraft formation flying.


  • Prof. E. Glenn Lightsey – School of Aerospace Engineering (advisor)
  • Prof. Brian Gunter – School of Aerospace Engineering
  • Prof. Mary Weitnauer – School of Electrical and Computer Engineering
  • Dr. J. Russell Carpenter – Space Science Mission Operations, NASA Goddard Space Flight Center (GSFC)



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