Operational and explosion fragments in GEO and HEO region discovered

and observed by ISON network

Vladimir Agapov, Zakhary Khutorovsky, Igor Molotov

IAC 2013, September 23-27, 2013Beijing, China

International Scientific Optical Network

• ISON is an open international non-government project developed to be an independent source of data about space objects for scientific analysis and S/C operators

• Additional scientific goals – discovery and study of asteroids, comets and GRB afterglows

• ISON optical network represents one of largest systems specializing in observation of space objects

• Cooperation already joins 62 telescopes at 33 observation facilities of various affiliation in 14 countries, is coordinating by the Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences (KIAM) and maintaining with assistance of company “Astronomical Scientific Center”, JSC

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Map of ISON observatories

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Number of GEO and HEO objects observed by ISON by night in 2013

Origin of Observed Objects – GEO case

• Unknown as a rule for newly discovered objects• No immediate obvious hypothesis (exception – objects of new

launches, objects after a large maneuver, objects after known fragmentation or normal operation)

• Establishing of reliable hypothesis may require collection of significant amount of additional information on known objects (including spacecraft bus design, maneuvering capability, launch and orbital insertion sequence of operations etc.)

• High fidelity propagator might be required for long period propagations (years) with proper estimation of errors

• Orbital and supplemental information derived from measurements (brightness, including estimation of a phase angle function; A/m; indication of non-passive motion) is an essential part of data required for analysis

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Distribution of observing GEO objects by eccentricity and inclination

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Distribution of observing GEO objects by RAAN and inclination

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Distribution of observing GEO objects by eccentricity and A/m ratio

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Distribution of observing GEO objects by eccentricity and A/m ratio

(moderate and small A/m)

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GEO Objects Origin – Simple Hypothesis

• Discovered object is an operational fragment or AKM separated from a ‘parent body’ (separation event)

• No active changes of a trajectory occurred after the object separation from the ‘parent body’

• Complete or partial set of parameters of a ‘separation orbit’ is known or can be derived from available info

• ‘Parent body’ may perform maneuvers but only those which are not actively change parameters of it’s orbital plane

• Estimation of reasonable time (time interval) and place (range of GEO longitudes) for the separation event can be performed

Constraints:• A/m ratio does not exceed 1-1.5 m2/kg• Motion of the object is well predictable

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Simple Hypothesis – Examples of SuccessISON

number

Date of detection by

ISON

Associated ‘parent’ object

Comment

90176 25.11.2008 1970-093A DSP sunshade cover

95557 22.09.2011 1991-080B DSP sunshade cover

43218 15.01.2010 1994-084A DSP sunshade cover

95057 15.06.2011 1997-008A DSP sunshade cover

95569 14.12.2011 2007-054A DSP sunshade cover

90132 23.11.2008 1997-049B Meteosat 7 cover

95689 14.07.2012 2012-035B Meteosat 10 cover

95494 08.05.2011 1997-029A FengYun 2A debris

95389 09.03.2008 2004-042A FengYun 2C debris

90073 11.12.2007 2006-053A FengYun 2D debris

90195 15.02.2009 2008-066A FengYun 2E debris

90214 15.02.2012 2012-002A FengYun 2F debris

90070 06.08.2007 1981-076 AKM GSM-2

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DSP Sunshade Covers

• 23 DSP spacecraft launched (22 to GEO + 1 stranded at HEO)

• Sunshade cover protected IR-telescope from contamination during pre-launch and launch operations

• Separated from a spacecraft immediately after the spacecraft separation from an upper stage (Transtage or IUS Stage 2) one can expect to find covers at orbits with parameters similar to ones of the appropriate upper stage

• Moderate-to-high A/m ratio (0.5-1.5 m2/kg)

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Meteosat Covers• Each Meteosat released 2 covers:

– MVIRI cover and MVIRI cooler cover for the first generation spacecraft– SEVIRI entry baffle cover and SEVIRI passive cooler cover for the second

generation spacecraft

• Protect the sensitive surfaces against possible contamination• Total 20 covers are released from 10 spacecraft• Separated from a spacecraft during it’s drift to scheduled GEO slot• Moderate-to-high A/m ratio (0.5-1.5 m2/kg)• Covers released by Meteosat 9 observed jointly by KIAM and AIUB teams

almost immediately after separation13

FengYun 2 Debris

• Each FengYun 2 type spacecraft released at least one fragment

• The fragment is supposedly a protecting cover similar to Meteosat’s one of covers

• No additional information was found• Propagation of orbits for all discovered fragments of this type

revealed they were separated immediately after the parent spacecraft was reaching it’s initial GEO position

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HEO Observations by ISON

• Observations of objects at HEO are obtained mostly as an additional output of regular GEO surveys though limited Molniya apogee area surveys started in April 2012

• ISON collected measurements for 1388 HEO objects during first 8 months of 2013, including regular observations for 359 objects absent at SpaceTrack

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Distribution of inclination and period for HEO objects observing by ISON

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Distribution of eccentricity and inclination for HEO objects observing by ISON

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Origin of Observed Objects – HEO case

• Unknown as a rule for newly discovered objects• No immediate obvious hypothesis (rare exception – objects of new

launches, objects after a large maneuver)• Situation is more complex than for GEO – large amount of relatively

small fragmentation debris can be detected thanks to rapid variations in phase angle and distance between an individual object and an observer

• Many explosions occurred at HEO hard to separate fragments of one group from another

• Establishing of reliable hypothesis may require collection of significant amount of additional information on known objects (including spacecraft bus design, maneuvering capability, launch and orbital insertion sequence of operations etc.)

• High fidelity propagator sometimes is useless for long period propagations due to high uncertainties in atmosphere density models

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HEO fragments analysis – test case• A group composed of 41 objects discovered and tracked by ISON for

which orbital information is not available from other sources• Orbital parameters:

- inclination in range 17.43-21.11°, - RAAN in range 156.13-313.27°, - period in range 576.41-795.12 min, - eccentricity in range 0.5985-0.7572 and thus all perigee heights

below 4000 km• HEO orbits with such inclination are typical for launches from Xichang

(China): - BEIDOU G navigation satellites – inclination of GTO is 20.2-20.6° - TIANLIAN data relay satellites – inclination of GTO is 17.9-18.2°

• Two of CZ-3C launcher upper stages used to launch BEIDOU G satellites are exploded according to NASA information (launches BEIDOU G4 (Oct 31, 2010) and BEIDOU G5 (Feb 24, 2012))

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HEO fragments analysis – test case (cont.)

• Tricky selection of proper orbital parameters for analysis• Only combination of argument of perigee and RAAN seems

provide a clue for the first step• Additional steps are required to check whether other constraints

are satisfied (RAAN and argument of perigee at the explosion event date)

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HEO fragments analysis – test case (cont.)

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HEO fragments analysis – test case (cont.)

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HEO fragments analysis – test case (cont.)

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HEO fragments analysis – test case (cont.)

• The largest of subgroups (composed by 24 objects) has clear indication of it’s relation to the 2012-008 launch of BEIDOU G5 fragments of explosion of the CZ-3C upper stage

• Second subgroup (composed by 14 objects) has clear indication of it’s relation to the 2010-057 launch of BEIDOU G4 fragments of explosion of the CZ-3C upper stage

• 3 remained objects are not correlated yet with specific origin

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Conclusions• More than 15 millions of measurements (RA, DECL, visual

magnitude) are collected within the ISON project since 2003• Nearly 1800 GEO and nearly 1700 HEO objects are tracked

by ISON as of the mid of Sep 2013, including more than 800 ones without orbital data at SpaceTrack

• ISON team have started to develop techniques which would permit to establish clear correspondence between discovered object and their source of origin

• Several GEO operational fragments are correlated with objects from which they were separated.

• A few dozens of HEO objects discovered and tracked by ISON were correlated with two known on-orbit explosions for which there are no other public information available.

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Acknowledgements Great thanks to all ISON observers and engineers,

including Astronomical Scientific Center employers providing invaluable support in software developing and observation planning

Special thanks to the AIUB team for support of continuing multiyear cooperative GEO and HEO debris research especially for HAMR objects

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