Optical properties of GEO and HEO space objects population

discovered and tracked by ISON

Vladimir Agapov, Victor Stepanyants, Igor MolotovKeldysh Institute of Applied Mathematics RAS

Alexandr LapshinAstronomical Scientific Center “Project-technics”, JSC

29th ISTS ConferenceJune 2-9, 2013, Nagoya, Japan

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

• Cooperative project already joins 33 observation facilities of various affiliation in 14 countries. Overall coordination is performing by the Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences (KIAM).

• Maintenance and operation of the network is performing jointly by KIAM and Astronomical scientific center (ASC) “Project-technics”, JSC

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Map of ISON observatories

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• 5 telescope subsets- global GEO survey (down to 15.5m) - tracking of the faint (fainter than 15.5m) space debris at GEO

and GTO- tracking of bright GEO and HEO objects- HEO survey and extended GEO survey- asteroids researches • 3 network operation supporting groups:- optical telescope and mount design & production- observatory software elaboration- observation planning and data processing

ISON structure

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Global GEO survey subsystem: 8 of 22 cm, 4 of 25 cm and 1 of 50 cm telescopes with FOV of

3.5- 5.5 degree

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Subsystem for faint debris tracking:AT-64 Nauchny-1, RC-800 Mayaki, S-600 Andrushivka, AZT-8

Gissar, AZT-14 Mondy, Zeiss-600 Arkhyz, ORI-40 in Kitab, ORI-40 in Khuraltogot

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Subsystem for tracking of bright GEO and HEO objects: GAS-250 in Ussuriysk, BNC-250 in Uzhgorod, Sajen-TM in

Arkhyz, ORI-25 in Blagoveschensk, ORI-25 in Tiraspol, ORI-25 in Kislovodsk, PH-1 n Nauchniy-1, AZT-28 in Priozersk,

TAL-250 in Barnaul

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HEO survey (Nauchniy-1 and Kislovodsk) and extended GEO survey (Khuraltogot, Sanglokh,

Kislovodsk and Nauchniy-1) consist of telescopes

with FOV of 7 degree

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ISON Database

As of the mid of April 2013 stores:

• Measurement, orbital and descriptive information on ~4800 objects ever observed by ISON, including – more than 1800 ones in GEO region,

– more than 2700 ones at HEO orbits,

– more than 270 ones at MEO orbits.

• More than 15.6 millions of astrometric position (RA, DEC) measurements

• More than 14.8 millions of brightness measurements

• More than 2 millions records on estimated parameters of orbits and the corresponding covariance matrices of errors

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ISON Database HEO, MEO and GEO objects currently on-

orbit

The ISON database contains information for more than 3260 HEO, MEO and GEO objects currently on-orbit with orbits updating using ISON optical measurements

960 of these objects are newly discovered during 10 years of ISON work

270 HEO and GEO space debris objects are discovered in 2012 (compare to 168 ones discovered in 2011 and 61 – in 2010), 88 new ones are discovered already in 2013 (as of Jun 1st).

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HEO, MEO and GEO Objects in ISON Database

Objects associated with GTO launches

Objects associated with Molniya-type orbit launches

Objects originated in GEO

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Distribution of observing GEO objects by period and inclination

Discovered fragments

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ISON Database HEO, MEO and GEO objects brightness

More than 14.8 millions of valid brightness measurements for more than 3400 objects are obtained

4400 brightness measurements per each object in average are collected during processing CCD images obtained during normal observations (survey and tasking)

More than 10000 brightness measurements per object are collected for a group of the most often observed 450 objects (up to 55000 brightness measurements per individual object)

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Brightness distribution of observing GEO objects

Each object is assumed as a diffuse sphere with albedo of 0.15

Differences between diffuse sphere phase function and real phase function for particular object are ignored

Standard brightness (referring to a zero phase angle and 40000 km distance) is calculated for each object based on all collected measurements to the date

Objects are split into 3 groups: spacecraft, rocket bodies (upper stages, AKMs), fragments and objects of undetermined type

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ISON Tracked GEO Objects Distribution by Standard Magnitude – 1704 objects

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ISON Tracked GEO Objects Distribution by Standard Magnitude – 1704 objects

approx. 1 m size

approx. 10 cm size

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ISON Tracked GEO Fragments and Objects of Undetermined Type

approx. 1 m size

approx. 10 cm size

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ISON Tracked GEO Spacecraft Standard Magnitude vs. Launch Date

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ISON Tracked GEO Upper Stages Standard Magnitude vs. Launch Date

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HEO Observations by ISON

• Observations of HEO are obtained mostly as an additional output of regular GEO surveys

• Measurements are collected for 1585 HEO objects, including 270 ones for which data are not provided at SpaceTrack

• Data are not analyzed yet by an object type (spacecraft, upper stages, fragments) in a manner of GEO objects so only common data are presented

• Standard brightness (referring to 40000 km distance and zero phase angle) is calculated

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ConclusionsBrightness measurement information is collected for more than 4800 GEO, HEO and MEO objects in the ISON database, including 960 ones without orbital data at SpaceTrack

Analysis of GEO, HEO and MEO objects brightness distribution is performed. Comparison is made for standard brightness distribution for objects of different type and at different orbits.

Standard brightness distribution for HEO objects tracking by ISON seems is different to the one for GEO objects. But it is not possible to make a definitive conclusion at this moment. The study is continuing.

Variations of the standard brightness are studied.

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Acknowledgements Great thanks to all ISON observers and engineers

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

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