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Debris and re-entry burnout of spacecraft
2l-422, 1982 Vol.2, No.3, pp.l Printed in Great Britain. All rights reserved,
Adv. Space Res.
0273-4177/82/03012102$03.OO/O copyright © COSPAR
13b. DEBRIS AND RE-ENTRY BURNOUT OF SPACECRAFT K. S. W. Champion Air Force Geophysics Laboratory (AFSC), Bedford, Massachusetts, U.S.A.
Re-entry and debris of spacecraft have three potentially environmentally detrimental effects. One is from physical impact on living or inanimate objects on or near the surface of the earth; a second is from possible harmful effects of the debris on the ground (for example, from radioactivity), and the thixd is from material, that is deposited in the upper ataiosphere from a vehicle that burns up during re-entry. 1. As far as is known, to date no living object has been hit, nor has any significant physical damage been done, by a re-entering spacecraft. The chance that any single person be hit by a large re—entering spacecraft is about 1 in 6xl011, but the chance that someone, somewhere be hit by a single large re—entering spacecraft is about 1 in 150. This means that, in the not distant future, someone (or some important physical object, such as a major building) is likely to be hit by a re-entering spacecraft. Active steps should be taken by satellite launching countries to avoid this possibility.
All
satellites or orbiting objects that are not expected to burn up before re—entry, and that have a finite orbital life, should have some means of disposing of the vehicle at the end of its useful life.
These methods include, but are not limited to, controlled re—entry (such as
on maimed vehicles), a destruction device, or a motor to lift the vehicle to a very high orbit, or away from the Earth’s gravitational field. It is not desirable to use an explosive destructive device while a satellite is in orbit because the resulting debris causes problems to a number of scientific observations, including optical and radio astronomy. However, it might be possible to destroy the vehicle as it begins to re—enter, but this still may have some harmful effects (see para. 3). In the future it may be possible to use systems such as the Space Transportation System (Shuttle) to pick up low-altitude satellites that have completed their useful lives and return them to Earth. This method, controlled re—entry and ejection from the Earth’s gravitational field constitute the preferred disposal systems. Efl.evating a satellite to a higher, long—life orbit is an intermediate solution. Explosive destruction is one of the least desirable solutions. 2. All efforts should be made to avoid the fall of debris to the ground if it is likely to have harmful effects such as radioactivity, harmful bacteria or other undesirable living organisms. This can be in several ways. One method is not to use such materials in satellites in the first place or, if they are essential, to use one of the preferred end—oflife disposal methods indicated in para. 1.
122
K.S.W. Champion
3. Satellites that burn up before re—entry produce large quantities of vapour of metals, metal, oxides, solar cell material, insulation, fluids, including those from batteries, and other debris •
These materials may have harmful effects depending on the types of material,
quantities and the extent of their distribution in the upper atmosphere.
Some of the
material will become widely dispersed after a few hours and no longer detectable. Some of the heavier material may settle into the stratosphere where it may have a long life. The questions to be posed are: how harmful is the material, and how do the quantities compare with other pollutants that are in the atmosphere? It is believed that, at the present time, these effects will not be large compared with the effects of other polluting sources, such as large rocket launches, aircraft and industrial activities. In the future, if there were large numbers of large vehicles burning up on re-entry, then there would be a pollution problem but, with present plans for controlled re—entry of most large vehicles (such as Shuttle), it does not appear to present a significant problem in the foreseeable future.
Adv. Space Res.
0273-4177/82/03012102$03.OO/O copyright © COSPAR
13b. DEBRIS AND RE-ENTRY BURNOUT OF SPACECRAFT K. S. W. Champion Air Force Geophysics Laboratory (AFSC), Bedford, Massachusetts, U.S.A.
Re-entry and debris of spacecraft have three potentially environmentally detrimental effects. One is from physical impact on living or inanimate objects on or near the surface of the earth; a second is from possible harmful effects of the debris on the ground (for example, from radioactivity), and the thixd is from material, that is deposited in the upper ataiosphere from a vehicle that burns up during re-entry. 1. As far as is known, to date no living object has been hit, nor has any significant physical damage been done, by a re-entering spacecraft. The chance that any single person be hit by a large re—entering spacecraft is about 1 in 6xl011, but the chance that someone, somewhere be hit by a single large re—entering spacecraft is about 1 in 150. This means that, in the not distant future, someone (or some important physical object, such as a major building) is likely to be hit by a re-entering spacecraft. Active steps should be taken by satellite launching countries to avoid this possibility.
All
satellites or orbiting objects that are not expected to burn up before re—entry, and that have a finite orbital life, should have some means of disposing of the vehicle at the end of its useful life.
These methods include, but are not limited to, controlled re—entry (such as
on maimed vehicles), a destruction device, or a motor to lift the vehicle to a very high orbit, or away from the Earth’s gravitational field. It is not desirable to use an explosive destructive device while a satellite is in orbit because the resulting debris causes problems to a number of scientific observations, including optical and radio astronomy. However, it might be possible to destroy the vehicle as it begins to re—enter, but this still may have some harmful effects (see para. 3). In the future it may be possible to use systems such as the Space Transportation System (Shuttle) to pick up low-altitude satellites that have completed their useful lives and return them to Earth. This method, controlled re—entry and ejection from the Earth’s gravitational field constitute the preferred disposal systems. Efl.evating a satellite to a higher, long—life orbit is an intermediate solution. Explosive destruction is one of the least desirable solutions. 2. All efforts should be made to avoid the fall of debris to the ground if it is likely to have harmful effects such as radioactivity, harmful bacteria or other undesirable living organisms. This can be in several ways. One method is not to use such materials in satellites in the first place or, if they are essential, to use one of the preferred end—oflife disposal methods indicated in para. 1.
122
K.S.W. Champion
3. Satellites that burn up before re—entry produce large quantities of vapour of metals, metal, oxides, solar cell material, insulation, fluids, including those from batteries, and other debris •
These materials may have harmful effects depending on the types of material,
quantities and the extent of their distribution in the upper atmosphere.
Some of the
material will become widely dispersed after a few hours and no longer detectable. Some of the heavier material may settle into the stratosphere where it may have a long life. The questions to be posed are: how harmful is the material, and how do the quantities compare with other pollutants that are in the atmosphere? It is believed that, at the present time, these effects will not be large compared with the effects of other polluting sources, such as large rocket launches, aircraft and industrial activities. In the future, if there were large numbers of large vehicles burning up on re-entry, then there would be a pollution problem but, with present plans for controlled re—entry of most large vehicles (such as Shuttle), it does not appear to present a significant problem in the foreseeable future.