Space Situational Awareness Forum - CNES Presentation

Operational Flight Dynamics

CNES Toulouse, France

Monique MOURY [email protected]

Hyattsville, SSA 2015 May 12, 2015

CNES role in French Space Surveillance

mailto:[email protected]

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SSA 2015 – French SSA 2

MITIGATION

OPERATIONAL ACTIVITIES

FOCUS on COLLISION AVOIDANCE

SSA 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


Objective => protection of:

People

Public health

Properties

Environment on Earth, in Atmosphere or in Orbit

Directly derived from ISO 24113

Compliant 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 MITIGATION

Technical Regulations


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



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



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

Launch window 0 3600 s

Closed instants



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



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



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


ORERATIONAL ACTIVITIES

In-orbit Collision Avoidance is essential

2007 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 Assessment

Conjunction 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


CSM: what is it ?


Conjunction message, an information message

=

Conjunction Data Message since April 2014


CDM: what is it ?


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 …

Middle Man Concept Conjunction Assessment is a two-step process

Space Surveillance Network

JSpOC

Precise complete catalog

Screening – Information Messages generation

Avoid… the avoidable


O/O

JSpOC

Ephem.

CAESAR Conjunction Analysis and Evaluation Service : Alerts and Recommendations

Flight Dynamics

System

(SPADOC)

Flight Dynamics

System (X)

ΔV

ΔV

CASR

JWD = CAESAR

WARN ALERT

Flight Dynamics

System (JOCC)

On Call analyst On Call analyst

JWD = Analyst

On Call O/O

JWD = O/O

CDMs-JSPOC

CDMs-ALM

CDMs-GNOSE

GO

TC

ΔV Δ

V

Screening

additional

measurement (when

available)

Almanac

Improved OD

ΔV


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


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.

https://spod.cnes.fr

[email protected]

Space Situational Awareness Forum - CNES Presentation

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