CNES role in French Space Surveillance

Transcription

1 CNES role in French Space Surveillance Monique MOURY Operational Flight Dynamics CNES Toulouse, France TOKYO, JSF SSA Symposium February 2015

2 SUMMARY MITIGATION OPERATIONAL ACTIVITIES FOCUS on COLLISION AVOIDANCE 2 JSF SSA Symposium 2015 French SSA

3 SPACE DEBRIS MITIGATION French Space Act JUNE 2008 Objective: To authorize and to monitor space activities when France bears international responsibility Shall obtain an authorization since DEC 10: Any operator launching or controlling a space object from French territory or French facilities Any French operator launching a space object from anywhere Any French operator controlling a space object in orbit Authorizations are granted by the Ministry in charge of space based on: Administrative review of the main characteristics of the company Technical review: compliance to the Technical Regulations is checked by CNES on behalf of the Ministry in charge of space 3

4 SPACE DEBRIS MITIGATION Technical Regulations Objective => protection of: People Public health Properties Environment on Earth, in Atmosphere or in Orbit Directly derived from ISO Compliant with IADC and UN-COPUOS Mitigation Guidelines A 10-year transition period is foreseen ( ) During this period, some of the requirements may be not fulfilled: the operator shall demonstrate that best efforts have been accomplished taking in account the existing design After the transition period all the requirements will be mandatory 4

5 SPACE SURVEILLANCE French Organization Overall responsibility belongs to Defense CIE: «Commandement Interarmées de l Espace», Joint Space Command Air Force Operational organization is shared between Air Force and CNES Air Force and Procurement Agency (Defense) Overall coordination Operation of the surveillance system (GRAVES) Operation of the tracking radars CNES (Research and Defense) Station keeping of civilian and military satellites In-orbit collision risk monitoring Launch collision risk monitoring Prediction of atmospheric reentries Flight dynamics support to Air Force Implementation of French Space Act 5

6 OPERATIONAL ACTIVITIES at CNES Maintenance of a catalog of orbits of LEO objects using GRAVES data Altitude < 1000 km 35 < inclination < 145 Launch collision avoidance French Space Act requires to take into account human space flights In-orbit collision avoidance Service delivered to all satellites controlled at CNES and open to external satellites Middle Man between Conjunction Message provider and operators End of life operations Transition phase for French Space Act requirements Atmospheric re-entry predictions 6

7 OPERATIONAL ACTIVITIES Launch Collision Avoidance Input data : Launched objects trajectory and dispersion (primary objects) manned vehicles trajectory and dispersion (secondary objects) Closing window criteria Output data : Closed instants in the launch window to avoid the collision risk Closed instants 0 Launch window 3600 s 7

8 OPERATIONAL ACTIVITIES End of life operations 30 years of improvements for end of life operations at CNES GEOSTATIONARY SATELLITES (since 1975) Symphonie : get out of the GEO ring Telecom 1 : complete reorbitation TDF : fluidic passivation Telecom 2 : reliability REMOTE SENSING SATELLITES (since 1985) Spot 1, 2 : lowering perigee Helios 1, SPOT 4 : fluidic passivation Spot 5, Helios 2, Pleiades : preparing the future MINI & MICRO SATELLITES (since 2000) Essaim : multiple disposal Demeter : fluidic passivation Parasol & Jason 1 : get out of operational orbit 8

9 OPERATIONAL ACTIVITIES End of life operations : synthesis CNES has controlled 39 satellites since 40 years and has performed EOL operations for more than half of them Many improvements, mainly concerning passivation and automation Still a lot to be done 17 : nominal operations, 1 : anticipated operations due to a payload component failure 2 : removed from operational orbit before end of life, to reduce risk towards other satellites in case of failure : it proved a wise decision for one of them. 2 : emergency situation, successfully handled 2 : lost with no possible disposal operations Through end of life operations and collision risk management, satellite operators contribute to prevent significant causes of space debris generation 9

10 OPERATIONAL ACTIVITIES Atmospheric re-entry predictions Objectives of the monitoring process: Detect objects representing a risk to French territory Detect French registered objects representing a risk to foreign countries Main steps: Long term:» Automatic screening of the catalogue, filtering based on perigee altitude» Ballistic coefficient estimation and lifetime determination Middle term (<2 months)» Orbit monitoring with dedicated CNES tool OPERA» Object characteristics and, when possible, fragmentation analysis» Risk computation Short term (< 3 days)» Tracking measurements, reentry prediction with uncertainties» On-ground track» Risk update 10

11 OPERATIONAL ACTIVITIES In-orbit Collision Avoidance In-orbit Collision Avoidance is essential 2007 January 11 th : Old Fengyun 1C satellite is deliberately destroyed by a missile (ASAT) Debris cloud of cataloged objects 2009 February 10 th : Operational Iridium 33 satellite collides with Cosmos 2251 satellite (not operational since 1995) 2 debris clouds of respectively 600 and cataloged objects Impact of those 2 events => ~50% of the detected close approaches in LEO involve a debris from one of those 3 clouds The Iridium Cosmos collision 11 could have been avoided...

12 Conjunction Assessment Conjunction Messages: a real satellite protection As a positive reaction to this situation Since 2009, JSpOC distributes conjunction messages to all satellite owners/operators (O/O) JSpOC O/O O/O O/O O/O O/O O/O 12

13 Conjunction Assessment CSM: what is it? Conjunction message, an information message = Conjunction Summary Message since July 2010 Time of the Closest Approach Orbit Determination characteristics Position/Velocity Position dispersion 13

14 Conjunction Assessment CDM: what is it? Conjunction message, an information message = Conjunction Data Message since April

15 Middle Man Concept Conjunction Assessment is a two-step process Space Surveillance Network JSpOC Precise complete catalog Screening Information Messages generation O/O must put in place an Acquisition, Evaluation, Alert and Recommendation process: Automatic acquisition : 24/7 Risk Evaluation: Alert FD team of the Control Center Recommendation for avoidance Only very few CMs lead to an avoidance action, but those messages (HIE) mustn t be missed. This process is not so easy Avoid the avoidable 15

16 CAESAR Conjunction Analysis and Evaluation Service : Alerts and Recommendations Flight Dynamics System (SPADOC) JSpOC CDMs-JSPOC CDMs-GNOSE CDMs-ALM Flight Dynamics System (JOCC) JWD = CAESAR CASR WARN ALERT Improved OD O/O Screening V JWD = Analyst GO V JWD = O/O Almanac On Call analyst On Call analyst On Call O/O V V V Flight Dynamics System (X) TC additional measurement (when available) Ephem. 16

17 Java for Assessment of Conjunctions JAC contributes to the collaborative work environment for CAESAR. JAC addresses the needs of teams responsible for managing in-orbit collision risks for one or many satellites. JAC helps to retrieve and analyze close approach alerts by providing a synthetic vision of each close approach described by CDMs. It helps the user to evaluate the level of risk according to its own criteria and to take and validate a decision. JAC is a modular software : JAC Basic Module: to be aware of the situation. JAC Expert Module: to take and validate a decision. JAC is distributed by CNES after signature of a license 17

18 In-orbit Collision Avoidance Synthesis JSpOC s CDMs combined with O/O data thanks to Middle Man entities are the best available data to avoid collision in space: All the O/O should take into account JSpOC s CDMs: but it is not an easy process; The Middle Men can help O/O and improve the reliability of the process; Reliability of the process protects space environment for the benefit of all, but does not guarantee individual satellite protection => public role (for ex European Commission decision for EU service) CAESAR (the French Middle Man) relies on JAC software for its essential collaborative work environment. Some of the difficulties of CA: Take into account maneuvers => LARGE CRITERIA Deal with huge amount of CDMs => BURDEN-SHARING BETWEEN JSpOC & Middle Man Risk level sensitivity to small variations of input data => EXPANDED PoC JAC, distributed by CNES in 2 levels, can help: Basic ( to be aware of the situation ) for free; Expert ( to take and validate a decision ) for an annual fee. jac@cnes.fr 18