Operational and explosion fragments in GEO and HEO region discovered and observed by ISON network

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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, 2013
• Beijing, China

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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
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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
  its 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 Success
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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 its 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
  separation

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FengYun 2 Debris

• Each FengYun 2 type spacecraft released at least
  one fragment
• The fragment is supposedly a protecting cover
  similar to Meteosats 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 its 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 its 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 its 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