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2006 | Buch

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Space Debris

Models and Risk Analysis

verfasst von: Dr. Heiner Klinkrad

Verlag: Springer Berlin Heidelberg

Buchreihe : Springer Praxis Books

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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In Space Debris Models and Risk Analysis the authors will provide the reader with a comprehensive background to understand the various sources of space debris, and to assess associated risks due to the current and future space debris environment. Apart from the non-trackable objects produced by historic on-orbit fragmentation events, several other sources of space debris will be outlined. Models will be described to allow the generation and propagation of the different debris families and permit the assessment of the associated collision risk on representative target orbits for present and future conditions. Using traffic models and possible mitigation practices, the future evolution of the space debris environment will be forecast. For large-size, trackable objects methods will be described for conjunction event predictions and related risk assessments. For hazardous re-entry objects, procedures will be outlined to enable the prediction of re-entry times and likely impact areas, to assess uncertainties in these factors, and to quantify the risk due to ground impact. Models will also be described for meteoroids, which prevail over space debris at small particle sizes.

Inhaltsverzeichnis

Frontmatter

1. Introduction

H. Klinkrad

2. The Current Space Debris Environment and its Sources

H. Klinkrad

3. Modeling of the Current Space Debris Environment

Abstract

The description of the space debris environment and its sources in Chapter 2 reflects a widely accepted, common understanding among space debris researchers. There are, however, different methods in existence for reproducing the observed environment by means of mathematical and physical models of release processes, for propagating orbits of release products, and for mapping the propagated environment onto spatial and temporal distributions of object densities, transient velocities, and impact fluxes. The subsequent chapters will focus on methods which have been developed at ESA, or under ESA contracts in context with ESA’s MASTER-2001 model (Meteoroid and Space Debris Terrestrial Environment Reference, (Bendisch et al., 2002)). At the end of this chapter a general overview of some of the most prominent space debris environment models will be provided.

H. Klinkrad, P. Wegener, C. Wiedemann, J. Bendisch, H. Krag

4. Modeling of Collision Flux for the Current Space Debris Environment

Abstract

The terrestrial space environment of intact objects and space debris was characterized in Chapters 2 and 3 for particle diameters ranging from 1 µm to catalog sizes. The collision flux resulting from this environment for an object of a certain size on a given target orbit will be determined in the present chapter.

H. Klinkrad, P. Wegener, J. Bendisch, K. Bunte

5. Modeling of the Future Space Debris Environment

Abstract

In Chapters 3 and 4 the historic evolution of the space debris environment up to the present was developed. All deployment and release events were largely considered as deterministically known, with traceable release epochs, release types, and release orbits. When trying to forecast the future evolution of the space debris environment, this deterministic knowledge base needs to be replaced by a statistical model of deployment and release events, based on a thorough analysis of past activities and recent trends. The current chapter will explain corresponding “traffic models” and their effect on the long-term evolution of the space debris environment in the case of unchanged operational practices (a so-called “business-asusual” scenario). The expression “long-term” in this context refers to forecasting timespans of up to 100 years. Traffic models, prediction methods, and resulting trends, which are discussed hereafter refer to the DELTA 2.0 software (Debris Environment Long-Term Analysis (Walker et al., 2000)).

H. Klinkrad, C. Martin, R. Walker

6. Effects of Debris Mitigation Measures on Environment Projections

Abstract

Chapter 5 outlined the consequences of continuing space activities in a businessas-usual fashion, with the conclusion that a timely change of operational practices is required in order to maintain a stable space debris environment, which will permit safe space operations in the long-term future. The main driver for future debris proliferation was found to be the on-orbit mass reservoir, predominantly of LEO objects beyond 100 kg, and potential large-size colliders (mission-related, or due to on-orbit explosions), capable of producing catastrophic break-ups. These break-ups may lead to enhanced feedback collisions and to the onset of a selfsustained runaway situation due to collisional cascading. In the current chapter debris mitigation measures will be identified that can effectively tackle the main causes of an uncontrolled population growth.

H. Klinkrad, C. Martin, R. Walker, R. Jehn

7. Hypervelocity Impact Damage Assessment and Protection Techniques

Abstract

Spacecraft which operate in densely populated altitude regimes are experiencing a steady debris and meteoroid particle flux which strongly increases with decreasing particle sizes (see Table 3.2 and 3.3, and Fig. 2.38). The consequences of resulting impacts can range from small surface pits for µm-size impactors, via clear hole penetrations for mm-size objects, to partial or complete destruction via shockwaves for projectiles larger than a few centimeters. The most probable impact velocities are in the range from 0 to 15 km/s for space debris, and between 5 km/s and 30 km/s for meteoroids (denoted as hypervelocity impacts or HVI). At such speeds, the impact of an aluminum sphere of 1 cm diameter deploys the same energy as an exploding hand-grenade, with equally devastating consequences, unless special protection measures are applied.

H. Klinkrad, H. Stokes

8. Operational Collision Avoidance with Regard to Catalog Objects

Abstract

In previous chapters all collision flux estimates and corresponding collision probabilities were purely based on stochastic methods which did not consider the estimated orbital positions of objects. While orbits of the whole debris population were propagated across the historic evolution of the environment, the coarse first-order prediction methods were only used to derive time histories of spatial object densities and transient velocities in a gridded 3D control volume. Such statistical assessments are justified for small debris objects which were generated by stochastic release models into orbits with poorly known initial conditions. For larger-size objects, however, USSTRATCOM is maintaining a catalog of tracked objects (see Chapter 2), with routinely updated orbit information in a so-called Two-Line Element (TLE) format. When used with care, such data can be employed to improve the safety of operational spacecraft by means of a conjunction prediction and collision warning service for missions in densely populated orbital regions.

H. Klinkrad, J. Alarcón, N. Sánchez

9. Re-Entry Prediction and On-Ground Risk Estimation

Abstract

In Chapter 4 and 8 the statistical and quasi-deterministic collision risk was analyzed for modeled and trackable objects of the on-orbit population. When focusing on the trackable catalog objects in 2002, this on-orbit population represented only 33.3% of all launched objects since Sputnik 1, with only 16% of their total mass, and 33.0% of their cross-sectional area. The present chapter will hence be devoted to an analysis of the risk potential due to the large number of objects which re-enter into the Earth atmosphere.

H. Klinkrad, B. Fritsche, T. Lips, G. Koppenwallner

10. Modeling of the Terrestrial Meteoroid Environment

Abstract

During almost 50 years of space activities approximately 27,000 tons of man-made material re-entered into the Earth atmosphere at a mean rate of ∼600 tons per year. This compares with an estimated 40,000 tons of natural meteoroid material which reaches the Earth atmosphere each year. If this is so, why are meteoroids only dealt with at the end of this book? The answer lies in the size spectrum of meteoroids, which is dominated by particles with diameters of ∼200 µm and corresponding masses of ∼1.5 × 10⁻⁵ g. The resulting risk to operational spacecraft is generally low as compared with space debris, in spite of much higher impact velocities of up to 72 km/s (corresponding to a heliocentric escape orbit of 42 km/s intercepted by the Earth orbit at 30 km/s).

H. Klinkrad, E. Grün

11. Space Debris Activities in an International Context

Abstract

Space debris is a problem of the Earth environment with global dimensions, to which all spacefaring nations have contributed during half a century of space activities. As the space debris environment progressively evolved, it became evident that understanding its causes and controlling its sources is a prerequisite to ensure safe space flight also in the future. Space debris researchers and decision takers in space agencies and commercial space companies came to a consensus that this could only be achieved through international cooperation.

H. Klinkrad

Backmatter

Titel: Space Debris
verfasst von: Dr. Heiner Klinkrad
Verlag: Springer Berlin Heidelberg
Electronic ISBN: 978-3-540-37674-3
Print ISBN: 978-3-540-25448-5
DOI: https://doi.org/10.1007/3-540-37674-7

Springer Professional

Über dieses Buch

Inhaltsverzeichnis

Frontmatter

1. Introduction

2. The Current Space Debris Environment and its Sources

3. Modeling of the Current Space Debris Environment

4. Modeling of Collision Flux for the Current Space Debris Environment

5. Modeling of the Future Space Debris Environment

6. Effects of Debris Mitigation Measures on Environment Projections

7. Hypervelocity Impact Damage Assessment and Protection Techniques

8. Operational Collision Avoidance with Regard to Catalog Objects

9. Re-Entry Prediction and On-Ground Risk Estimation

10. Modeling of the Terrestrial Meteoroid Environment

11. Space Debris Activities in an International Context

Backmatter

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