LEGEND (LEO-to-GEO Environment Debris model) is a three-dimensional orbital debris evolutionary model that is capable of simulating the historical and future debris populations in the near- Earth environment. The historical component in LEGEND adopts a deterministic approach to mimic the known historical populations. Launched rocket bodies, spacecraft, and mission-related debris (rings, bolts, etc.) are added to the simulated environment. Known historical breakup events are reproduced, and fragments down to 1 mm in size are created.

The LEGEND future projection component adopts a Monte Carlo approach and uses an innovative pair-wise collision probability evaluation algorithm to simulate the future breakups and the growth of the debris populations. This algorithm is based on a new “random sampling in time” approach that preserves characteristics of the traditional approach and captures the rapidly changing nature of the orbital debris environment.

LEGEND is a Fortran 90-based numerical simulation program. It operates in a UNIX/Linux environment.

This work was done by Jer Chyi Liou and Doyle T. Hall of Johnson Space Center. MSC-24805-1


NASA Tech Briefs Magazine

This article first appeared in the October, 2013 issue of NASA Tech Briefs Magazine.

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