1 ORBITAL DEBRIS: TOWARDS SUSTAINABLE SPACE ACTIVITIES PARIS SPACE WEEK 2015 Christophe BONNAL CNES – Launcher Directorate – Senior Expert Chairman – Space Debris Committee International Academy of Astronautics

CONTENT  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 2 Christophe BONNAL - Paris Space Week 2015 –

Charts from NASA Space Debris Office presenting catalogued objects  10 cm in LEO 1 m in GEO  Beware the exaggerated size of the dots … GROWTH OF THE EARTH SATELLITE POPULATION Texte1 Texte2 Texte1 Texte Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Texte1 Texte2 Texte1 Texte Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

GROWTH OF THE EARTH SATELLITE POPULATION Cataloged objects >10 cm diameter Christophe BONNAL - Paris Space Week 2015 –

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 Number of successful orbital launches per year Christophe BONNAL - Paris Space Week 2015 –

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 15 Christophe BONNAL - Paris Space Week 2015 –

SITUATION IN ORBIT: NUMBER OF CATALOGUED OBJECTS (NASA) 16 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 –

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 17 Christophe BONNAL - Paris Space Week 2015 –

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) 18 Christophe BONNAL - Paris Space Week 2015 –

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 1986 Upper Stage of Pegasus XL: 601 catalogued debris in 1996  Examples of voluntary fragmentations (59): Feng-Yun 1C: 3000 catalogued debris in 2007 USA-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 today 19 Christophe BONNAL - Paris Space Week 2015 –

COLLISION IRIDIUM 33 – COSMOS 2251 (AGI) 20 Christophe BONNAL - Paris Space Week 2015 –

 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) 21 KESSLER SYNDROME Christophe BONNAL - Paris Space Week 2015 –

22 DENSITY OF OBJECTS IN LEO (Source NASA) A-train Essaim – Demeter Iridium Orbcomm Spot Radarsat Envisat ERS Corot Jason TOPEX/Poseidon Globalstar Rapideye Meteor Christophe BONNAL - Paris Space Week 2015 –

23  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 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 –

24 POTENTIAL ACTIONS: SHIELDING Christophe BONNAL - Paris Space Week 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…

25 POTENTIAL ACTIONS: COLLISION AVOIDANCE Christophe BONNAL - Paris Space Week 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

27 POTENTIAL ACTIONS: REMEDIATION – ACTIVE DEBRIS REMOVAL Christophe BONNAL - Paris Space Week 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

28 CONCLUSIONS Christophe BONNAL - Paris Space Week 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