MAIN SPACE DEBRIS 2006 ACTIVITIES IN FRANCE

Fernand ALBYCentre National d’Etudes Spatiales

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BACKGROUND

UN COPUOS STSC

Mitigation GuidelinesIADC

Mitigation GuidelinesEuropean

Code of Conduct

principles

technical guidelines

applicable rules

Applicable to new projectsRecommended for objects already in orbit

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IMPLICATIONS

�Activities of the projects to demonstrate compliance

�Activities to support the future projects:

�Knowledge of the environment: optical observation from ground

�Research and Technology: search for innovative solutionsinflatable devices, behavior of tanks under debris impact

�Operational activities for on-orbit satellites: collision risk management and atmospheric reentry

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OPTICAL OBSERVATIONS OF DEBRIS IN GEO

�System developed several years ago (Tarot)

�On-going improvements of the system:� Image processing�Accuracy of the datation process

�Operational utilization:�Participation to the IADC campaigns�Monitoring of close approaches in GEO

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Inmarsat 3F5

� Sequence � Epoch : 2006-12-09 18:10� Pointing : 25 degrees GEO

OPTICAL OBSERVATIONS OF DEBRIS IN GEO

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Inmarsat 3F5 : sequence 1

Inmarsat 3F5

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Inmarsat 3F5 : sequence 1

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Inmarsat 3F5 : sequence 1

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Inmarsat 3F1

� Sequence� Epoch : 2006-12-09 20:15� Pointing : 64 degrees GEO

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Inmarsat 3F1

Intelsat 601

Intelsat 906

Inmarsat 3F1

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Inmarsat 3F1

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Inmarsat 3F1

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Inmarsat 3F2

� Sequence� Epoch : 2006-12-10 00:20� Pointing : -15.5 degrees GEO

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Inmarsat 3F2

Inmarsat 3F2

Cosmos 2319

Telstar 12

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Inmarsat 3F2

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Inmarsat 3F2

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Inmarsat 4F1

� Sequence� Epoch : 2006-12-09 19:15� Pointing : Two line elements (inclination greater than Tarot field of

view)

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Inmarsat 4F1

Inmarsat 4F1

Gorizont 27

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Inmarsat 4F1

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Inmarsat 4F1

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Satellite Microscope:Mass 210 kgOrbit altitude around 730 kmNo propulsion system (mission constraint)Orbital lifetime close to 60 years

RESEARCH AND TECHNOLOGYsearch for innovative solutions

Increase of the cross sectionwith a deployable system

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RESEARCH AND TECHNOLOGYsearch for innovative solutions

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RESEARCH AND TECHNOLOGYsearch for innovative solutions

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Impacts sur sandwich NIDA

Aluminum honeycomb(rear)

Impact P254 projectile Ø 7 mm, v = 5.6 km/s)

RESEARCH AND TECHNOLOGYhypervelocity impacts

Test bed

43rd UN-COPUOS STSC February 2007 25Impact 4833 (Ø 6 mm, v = 6.4 km/s)

RESEARCH AND TECHNOLOGYhypervelocity impacts

Tank after impact

X-ray photo of the impact

Test facility

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OPERATIONAL ACTIVITIES

�Collision monitoringClose encounter between Demeter and the 4 Essaim satellites

Conjunctions occur every 6 months

In June 2006 several close approaches atapogees between DEMETER and W23

On June 25 difference in altitude below 150 m

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CLOSE APPROACH DEMETER-ESSAIM

ESSW23

DEMETER

ESSE12

ESSE24

ESSW11

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Method :1. Identification and monitoring of the close approaches :

� Numerical computation of minimum distance in the local orbital frames� Graphical dynamic display 2D and 3D at the risky apogees

2. Identification of the orbit determination accuracy : =>statistical determination of a « security volume » around each spacecraft

3. Definition and approval by the project : � margins

4. Determination of the avoidance strategy (mission constraints) : � Latest date for the decision af an avoidance manoeuvre� Determination and validation of the avoidance manoeuvre

� Avoidance manœuvre performed by Demeter on June 21 at 11h59mn(�V=53 mm/s, decrease of apogee altitude 200m)

CLOSE APPROACH DEMETER-ESSAIM

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� Incorrect injection on orbit of the Arabsat 4A in March 2006� The final GEO orbit cannot be reached, the mission is lost� The satellite will remain a very long time on orbit, crossing all satellites between

480 and 14700 km altitude� Decision to perform a controlled reentry to fulfill the space debris and safety

requirements� On-ground risk analysis, nominal and degraded cases� Long duration boost: 4000 s� Successful deorbiting operations on March 23, 2006 (EADS-Astrium with CNES

support)

OPERATIONAL ACTIVITIESARABSAT 4A DE-ORBITING

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ARABSAT 4ATâche d'impact ARABSAT DT=4000s avec explosion

-50,0

-48,0

-46,0

-44,0

-42,0

-40,0

-38,0

-36,0

-34,0

-32,0

-30,0204 206 208 210 212 214 216 218 220 222

longitude

latit

ude

Monte Carlo 10000 cas

boite 10-5 DOORS

OPERATIONAL ACTIVITIESARABSAT 4A DE-ORBITING

Last ground track On-ground footprint

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SUMMARY

�Experience gained through application of the Code of Conduct to CNES projects

�Difficulties: Conflict between several constraints:• Mission objectives, • debris guidelines, • technical capacities• cost

�Need for:� better knowledge of the environment: optical observations� Search for new technical solutions� Support to operations: collisions monitoring and reentry