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Operational Flight DynamicsCNES Toulouse, France
Monique [email protected]
TOKYO, JSF SSA SymposiumFebruary 2015
CNES role inFrench Space Surveillance
SUM
MA
RY
JSF SSA Symposium – 2015 – French SSA2
MITIGATION
OPERATIONAL ACTIVITIES
FOCUS on COLLISION AVOIDANCE
JSF SSA Symposium – 2015- French SSA3
SPACE DEBRIS MITIGATIONFrench 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
JSF SSA Symposium – 2015- French SSA4
Objective => protection of:People Public healthProperties Environment on Earth, in Atmosphere or in Orbit
Directly derived from ISO 24113Compliant with IADC and UN-COPUOS Mitigation Guidelines
A 10-year transition period is foreseen (2010 – 2020)
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
SPACE DEBRIS MITIGATIONTechnical Regulations
JSF SSA Symposium – 2015- French SSA5
SPACE SURVEILLANCEFrench Organization
Overall responsibility belongs to DefenseCIE: « Commandement Interarmées de l’Espace », Joint Space CommandAir Force
Operational organization is shared between Air Force and CNES
Air Force and Procurement Agency (Defense)Overall coordinationOperation of the surveillance system (GRAVES) Operation of the tracking radars
CNES (Research and Defense)Station keeping of civilian and military satellitesIn-orbit collision risk monitoringLaunch collision risk monitoringPrediction of atmospheric reentriesFlight dynamics support to Air ForceImplementation of French Space Act
JSF SSA Symposium – 2015- French SSA6
OPERATIONAL ACTIVITIESat CNES
Maintenance of a catalog of orbits of LEO objects using GRAVES dataAltitude < 1000 km35° < inclination < 145°
Launch collision avoidanceFrench Space Act requires to take into account human space flights
In-orbit collision avoidanceService delivered to all satellites controlled at CNES and open to external satellitesMiddle Man between Conjunction Message provider and operators
End of life operationsTransition phase for French Space Act requirements
Atmospheric re-entry predictions
JSF SSA Symposium – 2015- French SSA7
OPERATIONAL ACTIVITIESLaunch 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 collisionrisk
Launch window0 3600 s
Closed instants
JSF SSA Symposium – 2015- French SSA8
OPERATIONAL ACTIVITIESEnd of life operations
30 years of improvements for end of life operations at CNES
GEOSTATIONARY SATELLITES (since 1975)Symphonie : get out of the GEO ringTelecom 1 : complete reorbitationTDF : fluidic passivationTelecom 2 : reliability
REMOTE SENSING SATELLITES (since 1985)Spot 1, 2 : lowering perigeeHelios 1, SPOT 4 : fluidic passivationSpot 5, Helios 2, Pleiades : preparing the future
MINI & MICRO SATELLITES (since 2000)Essaim : multiple disposalDemeter : fluidic passivationParasol & Jason 1 : get out of operational orbit
JSF SSA Symposium – 2015- French SSA9
OPERATIONAL ACTIVITIESEnd 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 failure2 : 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 handled2 : 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
JSF SSA Symposium – 2015- French SSA10
OPERATIONAL ACTIVITIESAtmospheric re-entry predictions
Objectives of the monitoring process:Detect objects representing a risk to French territoryDetect 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
JSF SSA Symposium – 2015- French SSA11
OPERATIONAL ACTIVITIESIn-orbit Collision Avoidance
In-orbit Collision Avoidance is essential2007 January 11th :
• Old Fengyun 1C satellite is deliberately destroyed by a missile (ASAT)• Debris cloud of 2 000 cataloged objects
2009 February 10th :
• Operational Iridium 33 satellite collides with Cosmos 2251 satellite (not operational since 1995)
• 2 debris clouds of respectively 600 and 1 600 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
could have been avoided...
JSF SSA Symposium – 2015- French SSA12
Conjunction AssessmentConjunction Messages: a real satellite protection …
Since 2009, JSpOC distributes conjunction messages
to all satellite owners/operators (O/O)
As a positive reaction to this situation …
O/O O/O O/O O/O O/O O/O …
JSpOC
JSF SSA Symposium – 2015- French SSA13
Orbit Determination characteristics
Conjunction message, an information message=
Conjunction Summary Message since July 2010
Position/Velocity
Position dispersion
Time of the Closest Approach
Conjunction AssessmentCSM: what is it ?
JSF SSA Symposium – 2015- French SSA14
Conjunction message, an information message=
Conjunction Data Message since April 2014
Conjunction AssessmentCDM: what is it ?
JSF SSA Symposium – 2015- French SSA15
O/O must put in place an Acquisition, Evaluation, Alert and
Recommendation process:
Automatic acquisition : 24/7Risk Evaluation:Alert FD team of the Control CenterRecommendation 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 …
Middle Man ConceptConjunction Assessment is a two-step process
Space Surveillance Network
JSpOC
Precise complete catalog
Screening – Information Messages generation
Avoid… the avoidable
JSF SSA Symposium – 2015- French SSA16
O/O
JSpOC
Ephem.
CAESARConjunction Analysis and Evaluation Service : Alerts and Recommendations
Flight Dynamics System (SPADOC)
Flight Dynamics System (X)
∆V
∆V
CASR
JWD = CAESAR
WARN ALERT
Flight Dynamics System (JOCC)
On Call analystOn Call analyst
JWD = Analyst
On Call O/O
JWD = O/O
CDMs-JSPOC
CDMs-ALM
CDMs-GNOSE
GO
TC
∆V
∆V
Screening
additional measurement (when
available)
Almanac
Improved OD
∆V
JSF SSA Symposium – 2015- French SSA17
Java for Assessment of ConjunctionsJAC 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 evaluatethe 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
JSF SSA Symposium – 2015- French SSA18
In-orbit Collision AvoidanceSynthesis
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.
https://spod.cnes.fr