SPACE DEBRIS
PRESENT SITUATION
F.ALBY
CENTRE NATIONAL D’ETUDES SPATIALES
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POPULATION ORBITING THE EARTH
1960
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
2
POPULATION ORBITING THE EARTH
1965
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
3
POPULATION ORBITING THE EARTH
1970
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
4
POPULATION ORBITING THE EARTH
1975
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
5
POPULATION ORBITING THE EARTH
1980
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
6
POPULATION ORBITING THE EARTH
1985
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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POPULATION ORBITING THE EARTH
1990
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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POPULATION ORBITING THE EARTH
1995
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
9
POPULATION ORBITING THE EARTH
2000
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
10
POPULATION ORBITING THE EARTH
2005
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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POPULATION ORBITING THE EARTH
April 2008
Cataloged objects >10 cm diameter
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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SITUATION
Since 1957
-more than 4500 launches
-about 200 fragmentations in orbit
12 600 objects > 10 cm
(catalogued objects)
operational
satellites
abandoned
5%
satellites
20%
fragments
53%
300 000 objects between 1 and 10 cm
(non-catalogued objects)
upper stages
14%
operational
debris
8%
135 000 000 objects between 0,1 and 1 cm
(non-catalogued)
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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ORBITAL DISTRIBUTION
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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LIFETIME
The in-orbit lifetime is limited by residues of atmosphere
atmospheric drag, velocity decrease, reentry on Earth
Examples:
Space Station
SPOT
GEO transfer orbit
GEO transfer orbit
geostationary orbit
400 x 400 km
825 x 825 km
200 x 36000 km
600 x 36000 km
36000 x 36000 km
6 months-1 year
200 years
about 10 years
10 000 years
millions of years
risks:
low Earth orbit
high altitude orbit
reentry on Earth, risk of victims on ground
important lifetime: in-orbit collision risk
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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EVOLUTION: NUMBER OF CATALOGUED OBJECTS
(source NASA)
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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ON-ORBIT RISKS
■On-orbit objects have huge kinetic energy
■Even a « small » debris can inflict important damages
■There is no shielding able to resist to particles larger than 2
cm (ISS example)
■Example: aluminium sphere Φ=1 mm at 10 km/s
->perforation of a 4 mm aluminium thick plate
■Probability of collision (Spot):
Probability of collision in 1year with
objects
Size of the objects >0,1 mm >1 mm
>1 cm
>10 cm
probability
1
0,5
3 10-3
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
2 10-4
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ON-ORBIT RISKS
examples
Cerise (24 July 1996)
first confirmed collision
between 2 catalogued objects
Solar panels of the Hubble Space
Telescope: more than 5000
impacts visible to the naked eye
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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ON-ORBIT RISKS
example: Space Shuttle
Window impact STS 92
 10 mm, depth 2mm
Impact on the wing’s
leading edge
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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RISKS ON GROUND
■Atmospheric reentry of a space object:
 Very high velocity ~ 8 km/s
 Important heating, most of materials melt
 Aerodynamic loads
 Fragmentation or explosion of the vehicle around 75-80 km altitude
 Some materials survive to reentry: steel, titanium, composites,…
 20 to 40 % of the initial mass reach the ground
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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RISKS ON GROUND
Example: Delta II upper stage
1997, Georgetown, Texas
engine combustion
chamber
250 kg stainless steel tank
High pressure vessel
(30 kg)
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
Thermal
protection
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SUMMARY
•Increasing number of man-made objects orbiting the Earth
•Critical evolution if nothing is done
•Debris represent a risk to space missions in case of collision
•Debris represent a risk on ground in case of uncontrolled reentry
•Mitigation and remediation are necessary
International Interdisciplinary Congress on Space Debris, 7-9 May 2009, McGill University, Montreal, Canada
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