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Space Debris – Current Situation
Dr.-Ing. Carsten Wiedemann, Prof. Dr.-Ing. Peter Vörsmann
21. März 2012 | Carsten Wiedemann | Space Debris | Seite 2
Catalog
� 16,300 objects in the catalog � (some with a size of 5 cm)
� Of these, only 900 active satellites
21. März 2012 | Carsten Wiedemann | Space Debris | Seite 3
Objects greater than 10 cm
� 29,000 objects � greater than 10 centimeters
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Objects greater than 5 cm
� 60,000 objects � greater than 5 centimeters
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Objects greater than 1 cm
� 700,000 objects � greater than 1 centimeter
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Objects greater than 1 mm
� 200 million objects � greater than 1 millimeter
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Objects greater than one tenth of a millimeter
� Trillions of objects � greater than 0.1 millimeter
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Spatial Density (2009)
ENVISAT
ISS
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Spatial Density
Spatial density of debris larger than one centimeter according to
MASTER-2009
2005 2009
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Instability of the LEO Population
Increasing threat for the orbits used by Earth observation satellites
Spatial density of objects larger than one centimeter versus time on LEO according to
MASTER-2009
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Which satellites are most likely to collide?
Incli
na
tio
n i
n d
eg
Collisions will mainly occur between sun-synchronous satellites (i ≈ 98°) and objects
at i ≈ 82°. Basically head-on collisions with twice the orbital velocity!
Perigee altitude in km
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Conclusions
Orbital region of special interest: 800 km altitude• high number of space debris
• high collision velocity
• high probability of catastrophic collisions
Collisional cascading (Kessler Syndrom) will start in 800 km.
It may be necessary to remove existing objects actively.
Scientific/technical challenges• identification of long-living risk objects (potential collision partners)
• prioritization of risk objects for active removal
• active removal (de-orbiter rendevouz and docking with risk object)
Legal challenges• new satellites and rocket stages: implementation of an obligation for
immediate de-orbiting at EOL?
• old satellites and rocket stages:o can risk objects be removed by a third party?
o can someone be held responsible for a collision?