1 orbital debris: towards sustainable space activities paris space week 2015 christophe bonnal cnes...
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ORBITAL DEBRIS:
TOWARDS SUSTAINABLE SPACE ACTIVITIES
PARIS SPACE WEEK 2015
Christophe BONNALCNES – Launcher Directorate – Senior Expert
Chairman – Space Debris Committee
International Academy of Astronautics
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CO
NT
EN
T NUMBER OF OBJECTS IN ORBIT UNCONTROLLED REENTRY COLLISION RISKS SOURCES OF ORBITAL DEBRIS POTENTIAL SOLUTIONS MITIGATION RULES SHIELDING COLLISION AVOIDANCE REMEDIATION – ACTIVE DEBRIS REMOVAL
CONCLUSIONS
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
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Charts from NASA Space Debris Office presenting catalogued objects 10 cm in LEO1 m in GEO
Beware the exaggerated size of the dots…
GROWTH OF THE EARTH SATELLITE POPULATION
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1960
Cataloged objects >10 cm diameterChristophe BONNAL - Paris Space Week 2015 – 04.02.2015
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GROWTH OF THE EARTH SATELLITE POPULATION
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1965
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
1970
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
1975
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
1980
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
1985
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
1990
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
1995
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
2000
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
2005
Cataloged objects >10 cm diameter
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GROWTH OF THE EARTH SATELLITE POPULATION
2010
Cataloged objects >10 cm diameter
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NUMBER OF OBJECTS IN ORBIT
The number of objects in space strongly increases in time:
- Mainly in Low Earth Orbits (Region A = 2000 km, i)- Significant in Geostationary Orbit (Region B = GEO 200 km 15°)
- Despite the reduction in the number of launches compared to 70-80’s
- Despite mitigation rules since 1995 - 2002
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Mas
s in
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it (
mill
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s o
f kg
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Year
Monthly Mass of Objects in Earth Orbit by Object Type
Total Objects
Spacecraft
Rocket Bodies
Fragmentation Debris
Mission-related Debris
Number of successful orbital launches per year
1957
1961
1965
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1973
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1981
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2009
2013
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Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
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NUMBER OF OBJECTS IN ORBIT
Roughly 23,000 large objects in space:
17,200 catalogued objects
additional 6,000 non catalogued by US but identified
720,000 debris larger than 1 cm
135 million debris larger than 1 mm
U But space is very wide!
At a given time, only 18 large objects above France
Roughly 1000 active satellites (5 %):
450 in GEO 450 in LEO
100 elsewhere
functional satellites
5%non functional
satellites17%
upper stages13%
operational debris13%
fragments52%
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
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SITUATION IN ORBIT: NUMBER OF CATALOGUED OBJECTS (NASA)Iridium 33 – Cosmos 2251
Fengyun 1C
H8 V16
USA 193
HPAS Pegasus XL
Derival 214 / yr
Derival 1000 / yr
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
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RANDOM ATMOSPHERIC REENTRY
What goes up will go down: Orbital objects in Low Earth Orbit reenter atmosphere after some time
Residual atmosphere generates a drag which progressively lowers the orbit Atmospheric reentry leads to vaporization of most of the materials
Combination of heat flux and mechanical stresses during reentry
But roughly 10 to 20% in mass survive reentry (refractory materials, dense elements, Russian dolls effect, …)
No way to know with precision where and when an impact will occur High number of reentries:
1 or 2 catalogued objects per day
1 or 2 large integer object (satellite or stage) per week Potential casualty risk
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
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COLLISION RISKS
Collision risk in Sun Synchronous Orbit today is comparable to the unreliability of the satellite or of its launcher:
Collision occur between debris and operational spacecraft
Can lead to loss of function of an operational spacecraft
Very complex modelling:
steel debris of 1 cm radius = 1 MJ = Large car at 130 km/h aluminum debris of 1 mm radius = 1 kJ = Bowling ball at 100 km/h
Real criteria for catastrophic collision: impact > 40 J/g
Examples:
Probability of mission failure of Spot 5
3 to 5% over lifetime (CNES)
Probability of failure of Sentinel-1 over lifetime
Component loss = 53 %, Mission loss > 3,2 % (TAS-I)
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
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SOURCES OF ORBITAL DEBRIS
4 main debris sources:
Launches Example of 2014: 92 launches 334 catalogued objects today
Aging of materials (Thermal Protections, electrical cells, Mylars…)
Mainly very small debris
Fragmentations, voluntary or not
280 registered end of 2013
Examples of accidental fragmentation (154):
Upper Stage of Ariane V16 (Spot 1): 796 catalogued debris in 1986Upper Stage of Pegasus XL: 601 catalogued debris in 1996
Examples of voluntary fragmentations (59):
Feng-Yun 1C: 3000 catalogued debris in 2007USA-193 : 500 catalogued debris in 2008, none remaining today
Number is lowering thanks mainly to passivation measures
Collisions 5 official ones, 64 suspected with smaller debris
Example: Iridium 33 – Cosmos 2251 in 2009 2269 catalogued debris todayChristophe BONNAL - Paris Space Week 2015 – 04.02.2015
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COLLISION IRIDIUM 33 – COSMOS 2251 (AGI)
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A chain reaction is feared in Low Earth Orbit:
Two antagonist phenomenon
1. Permanent generation of new orbital objects
2. Natural cleansing of orbits by atmospheric drag
Chain reaction when 1 > 2
The higher the altitude the lower the drag is
but the lower the number of debris is and vice versa…
Known as the Kessler syndrome
Uncontrolled increase if the “collision” part of debris generation becomes lager than the “atmospheric cleansing”
No worldwide consensus yet: very complex studies
Suspected between 700 and 1100 km altitude (and 1500 km TBC)
KESSLER SYNDROME
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DENSITY OF OBJECTS IN LEO(Source NASA)
A-trainEssaim – Demeter
IridiumOrbcomm
SpotRadarsatEnvisat
ERS
Corot
JasonTOPEX/Poseidon
Globalstar
Rapideye
Meteor
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It is fundamental to comply with current mitigation measures:
1. Short term- Minimization of operational debris; no voluntary break-ups,- Systematic passivation to prevent accidental break-ups,- Two protected zones (LEO, GEO): 25 years rule.
2. Long term- Systematic deorbitation or escape.
Very wide number of reference documents:- IADC Guidelines (2002), - UN Guidelines (2007), - National Standards (CNES 1999), ESA Standard (2007)- European Code of Conduct (approved ASI-BNSC-CNES-DLR-ESA 2004),- ISO 24113 standard and second tier standards (under approval),- French Space Law LOS (approved 2008, into force since Dec.2010).
POTENTIAL ACTIONS: MITIGATION RULES
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
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POTENTIAL ACTIONS: SHIELDING
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
Satellites can be shielded against small impacts:
Wide variety of shields
Multi-walls concepts
large number of standards
Commonly applied on “manned” satellites (ISS, ATV…)
Typical limitation: 1 or 2 cm
Energy is too high above this limit
Strong impacts on satellite designs:
Thermal control, communications, mass, costs…
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POTENTIAL ACTIONS: COLLISION AVOIDANCE
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
In some cases, satellites can avoid a collision: Collision avoidance:
An operational satellite is maneuverable
Orbits of large debris can be predicted
Collisions with catalogued objects can be anticipated
A maneuver can be commanded prior to collision
Very complex modelling:
Need to have very accurate orbital parameters
Dedicated sensors are required (radars, telescopes)
Space Surveillance Systems
CNES offers an anti-collision service (CAESAR) to protect active satellites Orbital catalog produced by the radar system GRAVES
Protects collision on operational satellite, but does not prevent collisions between debris
POTENTIAL ACTIONS: COLLISION AVOIDANCE
French Space Surveillance Systems
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POTENTIAL ACTIONS: REMEDIATION – ACTIVE DEBRIS REMOVAL
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
Situation can be improved if the worst debris are retrieved: Active Retrieval of 5 to 10 debris every year could stabilize population:
Complex modelling: no consensus yet
Could be a long term solution
ADR can take a very wide range of solutions:
Contact-less: laser, electrostatic, ion-beam effect…
Contact without control: harpoon, clamp, net, air-bags, EDT…
Contact with control: robotic arm, tentacles…
Numerous studies at worldwide level
Strong synergies with “On Orbit Servicing”
No clear financial scheme yet Business plan is hard to understand
Legal, insurance, political, military problems
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CONCLUSIONS
Christophe BONNAL - Paris Space Week 2015 – 04.02.2015
Whatever the technical solution, an action shall be undertaken: Poor respect of remediation rules today:
Roughly 50% of the orbited objects cope with the 25-year rule
Numerous orbital objects are not passivated
Significant cost of proposed measures:
No clear conclusions yet
Costly deorbitation at end of life
Impact on design
No business plan for Active Debris Removal
Legal impact of proposed measures
No consensus on situation at worldwide level Actions at UN and IADC level (Inter Agency Coordination Committee)
Need for a revolution in mentalities “Clean” space operations
Long Term Sustainable Activities is questioned