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Space Debris – Current Situation

Dr.-Ing. Carsten Wiedemann, Prof. Dr.-Ing. Peter Vörsmann

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Catalog

� 16,300 objects in the catalog � (some with a size of 5 cm)

� Of these, only 900 active satellites

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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?