OPEN JOINT-STOCK COMPANY «RESEARCH-AND-PRODUCTION CORPORATION “PRECISION SYSTEMS AND INSTRUMENTS»

New ideas in retroreflector arrays development

V.P.Vasiliev, M.А.Sadovnikov, V.D. Shargorodskiy,

A.L.Sokolov

USA, 2014

New laser retroreflector array

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1.  LEO array – “PIRAMIDA”

2.  “BLITS-M”

3.  Ring retroreflector array for GLONASS

4.  Luna’s arrays

!55γ =To the Earth’s center

!10γ =

To the Earth’s center

!15β =

!08β =

Cross-section of “Piramida” 3

Target error

!55γ =To the Earth’s center

!10γ =To the Earth’s

center

!15β =

!08β =

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Retroreflector array Number of CCR

Mass Size Target error

Champ

4

210 g

110x110x48 mm

± 5 mm

CryoSat-2 7

300 g

∅114x50 mm

± 6 mm

Piramida 4

30 g

40x40x30 mm

> ± 1 mm

Retroreflector arrays comparison 5

Conclusions

"   Construction of the compact retroreflector system allows to reduce the measurement error of the range to a satellite up to 1 mm;

"   RCS is in the following limits: from 3,2·105 m2 up to 4·104 m2 at the elevation angle of 20° and from 1,2·104 м2 up to 5·103 м2 in the zenith area at the elevation angle 80°

"   Piramida will be set to student’s spacecraft «Baumanets-2»:

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Spherical glass satellite «BLITS»

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Spherical satellite «BLITS» in details

SC «Meteor-M» with spherical glass nanosatellite «BLITS» on board was launched on September 21, 2009. ILRS announced its support to the «BLITS» orbit. Basic parameters: - diameter……………………………………………..170 mm - mass………………………………………...……..7.5 kg - orbital altitude………………………………….. 835 km - CS…………………………………………........100000 m2 - target error……………………………………< 100 micrometers

Construction of SC «BLITS-M»

Inner sphere radius R2 64 mm Inner sphere material TF105

Outer radius R1 110,4 mm Outer lenses material K108

Mass 17 kg Ballistic coefficient 440 kg/m2

Altitude 2000 km CS

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1R

2R

Interference reflective coating

26 m 10)32( ⋅÷

Temperature distribution depending on SC size and thermal deformation for orbit №1. a – before entering the Earth’s shadow, b – before leaving it.

Orbital plane is parallel to the direction to the Sun

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Orbital plane is perpendicular to the direction to the Sun

Temperature distribution depending on SC size and thermal deformation for orbit №2

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Temperature effect on the SC «BLITS-M» diffraction pattern (FFDP)

CT o20−= CT o25−= CT o30−=

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26 m 10)32( ⋅÷CS at the FFDP axis is equal to

Concept of the SC «BLITS-S» construction

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Requirement Solution Implementation Zero signature Always reflects just one CCR 60 CCR. Maximum angle of incidence –

14о, aperture – 24 mm and blend altitude – 20 mm.

Increasing of CS CCR size and faces coverage optimization

CCR with a phase-correcting coating of lateral faces for the FFDP formation

without a central lobe. Absence of the “dead” zones where none of

the CCR reflects

Selecting both optimal angle between neighboring CCRs

and maximum angle of incidence

Angular distance between any neighboring CCRs is approximately equal to the

double angle of incidence.

Minimal variation of a systematic correction

Reduction of the sphere’s diameter. Reduction of the

maximum angle of incidence to CCR at the expense of

blends

Sphere’s diameter by the entering faces of CCR is equal to 168 mm and the carrier

sphere’s diameter – 210 mm.

Increasing of ballistic coefficient (BC)

Increase of the carrier sphere’s diameter and its material

density

For a heavy flint (TF5) the mass is equal to 18 kg,

And BC is equal to 550 kg/m2.

CCRs arrangement on SC «WESTPAC»

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This is an icosahedron. 3 CCR х 20 faces = 60 CCR.

Construction of SC «BLITS-S»

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Comparison of SC «BLITS», «BLITS -M» and «BLITS-S»

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Characteristic «BLITS»

«BLITS-M» «BLITS-S»

Diameter 170, 3 mm 220,8 mm 210 mm

Mass 7,46 kg 17 kg 18 kg Ballistic coefficient 327 kg/m2

435 kg/m2 550 kg/m2

Target error 0,1 – 0,3 mm 0,1 – 0,3 mm 0,6 – 1 mm Signature «zero»

«zero» Minor extension of a signal

RP type Central lobe with a ring-shaped minor-lobe

Central lobe with a ring-shaped minor lobe

Six minor lobes

RCS for 7 – 8 ang. sec.

Signal type at the angular velocity of

10 turns/minute

Clusters with the interval of 3 seconds

Clusters with the interval of 3 seconds

Sawtooth signal with the period of 0.5 seconds

26 м 10)8,05,0( ⋅÷ 26 м 10)4,10,1( ⋅÷26 м 10)2,01,0( ⋅÷

The ring retroreflector array for GLONASS

Basic ideas:

1. Increased aperture CCRs: 42 – 48 mm

2. DAO: 2” – 3” (single DA)

3. Interference dielectric coatings for reducing of

solar heating influence

4. Orientations of two-spot FFDP along the radius of

RRA

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Optimization of LR-array configuration 17

t t

S S

Fdaln_zoneFdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

CCRs with DAO + coatings. Diameter 48 mm. Dihedral angle 2,4”

Fdal n_zone

Fdaln_ zon e2

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 100

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

σ r 0, Z, ( ) 0.8⋅ 1⋅

r

rm2.277507235645023⋅

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 100

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200200

1.774

σ.036 r 0, Z, ( ) 0.8⋅ 36⋅

100 r

r.m2.277507235645023⋅

2” 4” 6” 8” 2” 4” 6” 8”

CS ( м2 ) 610⋅CS ( м2 ) 610⋅

10

20

30

50

100

150

200

18

1 CCRs 36 CCRs

Ring two-spot CCR array for GLONASS

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

Fdaln_zone

100− 50− 0 50 1000

0.01

0.02

0.030.023

0

S t 0, 0, 25, 0, ( )

S t 0, 0, 50, 0, ( )

100100− t

502 =τ

1002 =τ

19

50 -50

o5=θ

o5=θ

o10=θ

o10=θ

o15=θ

o15=θ

ps

ps

R = 265 mm d = 48 mm

-100 -200 100 200

-100 -200 100 200 300 -300

300 -300

t (ps)

t (ps)

400− 350− 300− 250− 200− 150− 100− 50− 0 50 100 150 200 250 300 350 4000

0.01

0.02

0.03

0.04

0.050.045

0

S.rmn t 25, 5, ( )

S.rmn t 25, 10, ( )

S.rmn t 25, 15, ( )

400400− t

400− 350− 300− 250− 200− 150− 100− 50− 0 50 100 150 200 250 300 350 4000

0.01

0.02

0.030.023

0

S.rmn t 50, 5, ( )

S.rmn t 50, 10, ( )

S.rmn t 50, 15, ( )

400400− t

Incident pulse

Standard deviation

50 ps 8 mm 8 mm 8 mm

100 ps 16 mm 16 mm 16 mm

o5=θ o10=θ o15=θ

Variants of Luna's arrays

Base characteristics: 1.  Standard CCRs: 28 mm; DAO: 0.

2.  Interference dielectric coatings.

3.  Compact array of 19 CCR.

4.  Size = 160 mm. Mass < 1 kg.

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1.  CCRs: 42 - 48 mm; DAO: 0.

2.  Interference dielectric coatings.

3.  Non-planar array of 11 - 13 CCR.

4.  Size = 310 mm. Mass < 2 kg.

CS = m2 810)5,23,2( ⋅− CS = m2 810)5,13,1( ⋅−

Conclusions

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Thus, new technical and technological solutions provide •  For LEO spacecrafts – a significant increase of laser ranging

accuracy (< 1 mm) and decrease of mass (50 g) •  For MEO spacecrafts – new super accuracy “BLITS” •  For navigation satellites - a significant increase of the

retroreflector array cross-section and get a higher laser ranging accuracy

•  For Luna’s station – compact and enough easy arrays with sufficient accuracy