LEGEND – a three-dimensional LEO-to-GEO debris evolutionary model

Liou, J.‐C.; Hall, D. T.; Krisko, Paula H.; Opiela, J.

doi:10.1016/j.asr.2003.02.027

Cited by 97 publications

(28 citation statements)

References 5 publications

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“…It is capable of simulating the historical and future debris populations in the near-Earth environment (Liou et al 2004;Liou 2005). The historical simulation in LEGEND covers the period from 1957 to the end of 2005 for this study.…”

Section: Model Descriptionmentioning

confidence: 99%

Instability of the present LEO satellite populations

Liou¹,

Johnson

2008

Advances in Space Research

159

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Several studies conducted during 1991-2001 demonstrated, with some assumed launch rates, the future unintended growth potential of the Earth satellite population, resulting from random, accidental collisions among resident space objects. In some low Earth orbit (LEO) altitude regimes where the number density of satellites is above a critical spatial density, the production rate of new breakup debris due to collisions would exceed the loss of objects due to orbital decay.A new study has been conducted in the Orbital Debris Program Office at the NASA Lyndon B. Johnson Space Center, using higher fidelity models to evaluate the current debris environment. The study assumed no satellites were launched after December 2005. A total of 150 Monte Carlo runs were carried out and analyzed. Each Monte Carlo run simulated the current debris environment and projected it 200 years into the future. The results indicate that the LEO debris environment has reached a point such that even if no further space launches were conducted, the Earth satellite population would remain relatively constant for only the next 50 years or so. Beyond that, the debris population would begin to increase noticeably, due to the production of collisional debris. Detailed analysis shows that this growth is primarily driven by high collision activities around 900 to 1000 km altitude − the region which has a very high concentration of debris at present.In reality, the satellite population growth in LEO will undoubtedly be worse than this study indicates, since spacecraft and their orbital stages will continue to be launched into space. Postmission disposal of vehicles (e.g., limiting postmission orbital lifetimes to less than 25 years) will help, but will be insufficient to constrain the Earth satellite population. To preserve better the near-Earth environment for future space activities, it might be necessary to remove existing large and massive objects from regions where high collision activities are expected.

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Section: Model Descriptionmentioning

confidence: 99%

Instability of the present LEO satellite populations

Liou¹,

Johnson

2008

Advances in Space Research

159

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“…It is supported by a fast, semi-analytical orbital propagator, a breakup model and a fast, pair-wise collision prediction algorithm based on the 'Cube' approach adopted in NASA's LEO-to-GEO Environment Debris model (LEGEND) [4].…”

Section: The Damage Modelmentioning

confidence: 99%

Synergy of debris mitigation and removal

et al. 2012

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At the beginning of the twenty-first century there was considerable effort made using evolutionary models to assess the effectiveness of post-mission disposal (PMD) and other mitigation measures to stabilise the growth of the debris population in low Earth orbit (LEO). Subsequently, this activity led to the recommendation of a "25-year rule" for the post-mission disposal of spacecraft and orbital stages intersecting the LEO region. At the time, it was anticipated that the 25-year rule, together with passivation and suppression of mission-related debris, would be sufficient to prevent the continued growth of the LEO debris population. However, in the last decade both the LEO debris environment and the debris modelling capability have seen significant changes. In particular, recent population growth has been driven by a number of major break-ups, including the intentional destruction of the Fengyun-1C spacecraft and the collision between Iridium 33 and Cosmos 2251. State-of-the-art evolutionary models now indicate that mitigation measures alone are insufficient to stabilise the LEO debris population.Consequently, this has led to considerable interest in the remediation of the debris environment and, especially, in debris removal. Yet there is a reluctance to revisit the role of PMD within the wider goal of remediation even though it does not provide the solution that was expected. Thus, there is a risk that the approach to remediation will follow a sequential, "over-the-fence" philosophy, which tends to deliver costly, and less than optimal solutions. In this paper, we present a new and large study of debris mitigation and removal using the University of Southampton's evolutionary model, DAMAGE, together with the latest MASTER model population of objects > 10 cm in LEO. Here, we have employed a concurrent approach to remediation, whereby changes to the PMD rule and the inclusion of other mitigation measures have been considered alongside multiple removal strategies. In this way, we have been able to demonstrate the synergy of these measures and to identify aggregate solutions to the space debris problem. The results suggest that reducing the PMD decay rule offers benefits that include an increase in the effectiveness of debris removal and a corresponding increase in the confidence that these combined measures will lead to the stabilisation of the LEO debris population.3

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“…The ADR vehicle then uses its primary chemical propulsion to transfer to the next target. Removal targets are identified and ranked using a fast, pair-wise collision algorithm based on the Cube approach employed by the LEO-to-GEO Environment Debris Model (LEGEND) [15] and applied to all objects in the US SSN catalogue. The approach determines the collision probability for each object using Monte Carlo (MC) simulation, whereby the number of MC samples effectively determines the amount of compute time required within the cloud-based solution.…”

Section: A Cloud-based Architecture Solution To the Ssa Case Studymentioning

confidence: 99%

Clouds in Space: Scientific Computing using Windows Azure

Johnston

O'Brien

Lewis

et al. 2013

Journal of Cloud Computing: Advances, Systems and Applications

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In this paper we report upon the cloud-based solution that we designed and implemented for space situational awareness. We begin by introducing the background to the work and to the area of space situational awareness. This concerns tracking the hundreds of thousands of known objects in near-Earth orbits, and determining where it is necessary for satellite operators to conduct collision-avoidance manoeuvres to protect their satellites. We also discuss active debris removal, which would be necessary to stabilise the debris population at current levels. We examine the strengths that cloud-based solutions offer in general and how these specifically fit to the challenges of space situational awareness, before describing the architecture we designed for this problem. We demonstrate the feasibility of solving the space situational awareness problem with a cloud-based architecture and note that as time goes on and debris levels rise due to future collisions, the inherent scalability offered by a cloud-based solution will be invaluable.

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LEGEND – a three-dimensional LEO-to-GEO debris evolutionary model

Cited by 97 publications

References 5 publications

Instability of the present LEO satellite populations

Instability of the present LEO satellite populations

Synergy of debris mitigation and removal

Clouds in Space: Scientific Computing using Windows Azure

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