• Publications
  • Influence
NASA's new breakup model of evolve 4.0
Abstract Analyses of the fragmentation (due to explosions and collisions) of spacecraft and rocket bodies in low Earth orbit (LEO) have been performed this year at NASA/JSC. The overall goals of thisExpand
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Polymer solution rheology based on a finitely extensible bead—spring chain model
Abstract A complete rheological equation of state for dilute polymer solutions is obtained by modelling the polymer molecules as bead—spring chains, in which the springs are finitely extensible.Expand
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A sensitivity study of the effectiveness of active debris removal in LEO
Abstract The near-Earth orbital debris population will continue to increase in the future due to ongoing space activities, on-orbit explosions, and accidental collisions among resident space objects.Expand
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Risks in Space from Orbiting Debris
340 C R E D IT : (T O P ) N A S A S ince the launch of Sputnik I, space activities have created an orbital debris environment that poses increasing impact risks to existing space systems, includingExpand
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The term “Kessler Syndrome” is an orbital debris term that has become popular outside the professional orbital debris community with out ever having a strict definition. The intended definition grewExpand
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Realistic human walking paths
  • D. Brogan, N. Johnson
  • Computer Science
  • Proceedings 11th IEEE International Workshop on…
  • 8 May 2003
We present a novel behavioral model of path planning that extends previous models through its significant use of pedestrian performance statistics that were obtained during a suite of experiments. Expand
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Modern Monopolies: What It Takes to Dominate the 21st Century Economy
What do Google, Snapchat, Tinder, Amazon, and Uber have in common, besides soaring market share? They're platforms - a new business model that has quietly become the only game in town, creating vastExpand
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Orbital Debris: the Growing Threat to Space Operations
For nearly 50 years the amount of man-made debris in Earth orbit steadily grew, accounting for about 95% of all cataloged space objects over the past few decades. The Chinese anti-satellite test inExpand
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A new look at the GEO and near-GEO regimes: Operations, disposals, and debris
Since 1963 more than 900 spacecraft and more than 200 launch vehicle upper stages have been inserted into the vicinity of the geosynchronous regime. Equally important, more than 300 spacecraft haveExpand
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Space traffic management concepts and practices
Abstract Concepts of space traffic management have been discussed for many years with little progress to date, due both to the complexity of the issue and to a perceived lack of urgency. Although aExpand
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