CNES role in French Space Surveillance

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


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


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


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


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


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


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


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


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...


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


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 ?


Conjunction message, an information message=

Conjunction Data Message since April 2014

Conjunction AssessmentCDM: what is it ?


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


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


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


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

[email protected]

Documents

CNES role in French Space Surveillance