Debris Aerospatiaux

RAeS 17/02/2009 Thibaut Labarre IENAC08S 1

Space Debris, a Threat to GNSS and its Applications to Civil Aviation

Current Situation Threat to Satellites Influence on GNSS Reliability Solutions

By Thibaut LABARRE

Student from the ENAC


History of Collisions

24 July 1996: Cerise Ariane V16 (debris)

17 January 2005: Thor (Stage) rocket CZ4 (debris)

December 1991 (collision identified in 2005): Cosmos 1934 Cosmos 926 (debris)

12 February 2009: Iridium Cosmos 2251


Current Situation (1/4)

Evolution of the number of debris (>10 cm) from 1960 to 2008

(1 centimeter = 0.393700787 inch)



GEO Space Debris 2008



Since 1957 : 4000 launches More than 200 fragmentations of orbiting objects

• 12,000 10 objects bigger than cm ( )referenced

• 200,000 1 10 objects sizing between and cm ( )not referenced

• 35,000,000 1 objects smaller than cm ( )not referenced

fragments

operating satellites

unoperating satellites

superior stages

operational debris


Curent Situation (4/4)


Threat to Satellites (1/3)

Probability of collision depends on Size of satellite Time spent in space Flux of debris

Collision probabilities for one year

>0.1 mm >1 mm >1 cm >10 cm

( =400 , =500Space Station h km S2)m

1 1 10-2 2 10-4

( =800 , =20 2)SPOT h km S m 1 0,5 3 10-3 2 10-4

( =1,500 , =16 2)Constellation h km S m 1 3 10-1 10-3 10-4

( =23,222 , =3 2 GALILEO h km S m body+ 16 2 )m solar arrays



Consequences of an impact Caracteristics of a space impact

Kinetic energy is linked to speed Orbital speeds are very high

Aluminium sphere at 10kmps A 1mm chip an average .22 long rifle bullet at gunpoint→ A peasized ball 180 kg safe travelling at 100 kmph→ A tennis ballsized sphere 25 sticks of dynamite→



Part of a solar array of the Hubble Space Telescope


Influence on GNSS Reliability (1/4)

What is GNSS? Global Navigation Satellite System Allows users to determine precisely where they are

on earth

What are its applications to Civil Aviation? Free Flight Landing procedures


COMPASS 2015


GALILEO 2013

GLONASS 2009

Projected development of GNSS

GPS 1995


MEO (GNSS orbits) still relatively spared Payloads Rocket Bodies Breakup Debris Anomalous Debris Totals

LEO 1612 758 651 3232 119 6372

MEO 126 28 2 0 0 156

GEO 587 116 1 2 0 706

Elliptical 249 515 135 167 0 1066

Unknown 171 120 185 0 0 476

Totals 2745 1537 974 3401 119 8776

Operational Debris

But debris will accumulate Operating lifespan of satellites : around 10 years Orbiting lifespan of satellites : millions of years Exponential growth due to fragmentation



Civil aviation imperatives for GNSS Accuracy Availability Continuity

Orbital debris endanger the last 2 imperatives ABAS technologies require more satellites to work The loss of a satellite during a critical phase of a

flight can have catastrophic consequences



Solutions (1/3)

Armor for GNSS satellites Pros

Enhances lifespan of satellites Cons

Expensive (in terms of weight) Covers only a fraction of the risk


Solutions (2/3)

Dodging the debris Pros

Enhances lifespan of satellites Cons

Every debris trajectory has to be tracked Fuel consumption increases


Solutions (3/3)

Disposal orbits for failed GNSS satellites Pros

Technically feasible Cheap Applicable to previous satellites

Cons GPS, GLONASS, GALILEO, COMPASS will all have

different orbits Disposal orbits may vary and become elliptical (due to

influence from the sun and the moon), interfering with operating satellite orbits


Conclusion

All the solutions are only partial and will not solve the problem

Cooperation: IADC, COPUOS, ISO


Thank you for listening!

Any questions?


References

/Les débris spatiaux : une pollution sous surveillance/, Lecture by Fernand Alby, Director of the CNES Space Debris Lab., ENAC Aerospace Challenges, jan. 2009

http://www.pollutionissues.com/ReSy/SpacePollution.html

http://www.aerospace.org/news/newsitems/procedures030702.html

Debris Aerospatiaux

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