Presentazione di PowerPoint

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ASTC Components
Temperature Range
LENS Best performance 20 C to 55C operative
from TBD to TBD
Heat Dissipation
CCD operative 30 C to 55C () non
operative 40 C to 80C
ASTCC 0.2Watt
ASTCC/ ASTCD operative 20 C to 55C
non operative 40 C to 80C
ASTCD 0.5Watt
ASTCE operative 20 C to 55C non
operative 40 C to 80C
ASTCE 3 Watt
() The CCD could be operational up to 55C but
over 35C/40C condition the system will not be
able to extract pointing direction from this
camera (noise).
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Thermal Interfaces
Conductive
M-Structure
Radiative
AMS_02/ Space
Si Tracker
TTCS
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AST Thermal Passive Control
SILVER TAPE
MLI
MLI collar
ASTS lens covered by MLI
Baffle in Black anodyzed out
Silver tape
a0.88 e0.78
a0.135 e0.63
MLI id1 proposal
By Christian Vettore (CGS)
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AST Thermal Passive Control Gap for MLI
Vs UToF
MLI integration? MLI ID1 interface?
Vs VC
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AST Thermal Active Control
CCD Thermal LINK Flexible copper strips
Thermal bridge Double copper strip
EL Board Thermal LINK Board edge copper strip
ASTS THERMAL BLOCKS Copper blocks
ASTS THERMAL CONNECTORS Copper blocks
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Star Tracker Thermal analysis

• Star Tracker thermal analysis activities
  constitute an interactive effort between INFN
  Roma, Carlo Gavazzi and Carso.
• INFN Roma thermally models the star tracker and
  performs detailed thermal and thermo elastic
  analysis
• CGS integrates star tracker model in AMS-02
  overall model and produce to INFN Roma I/F data
  for standard hot and cold cases and devolopes a
  non standard procedure for special cases
  individuated by CARSO
• CARSO performs star tracker visibility study and
  individuates special cases to be thermally
  analysed. These cases refer to orbital condition
  with low values for the sun angle (angle between
  lens axis and star tracker_sun direction)

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ASTCL - Lens Thermal Model
Lens cylinder
Lens cylinder
0.4
0.38
1(W)
0.36(W)
0.02
0.45
0.02
FILTER
LENS FRONT
LENS BACK
CCD
Q (W) Power transmitted
Q (W) Power absorbed
Filter blue red Transmittance 0.4 Absorption
0.45 Reflectance 0.15
Lens Transmittance 0.9
Radiative coupling
Conductive coupling
The total amount of flux entering the lens is
determined by the total flux on the filter
multiplied by the transmittance
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Star Tracker Analysis cases
Following cases under analysis Nominal Hot
B751515-15_hot B_0-2-101_hot
B75-15-20-15_hot Additional Hot
Filter Sun directly in the filter
B42_0_0_0_hot B-21_0_0_0_hot baffle
Sun in the baffle B71_0_0_0_hot
Nominal Cold B_0_0_0-15
B-2515-2015 B25-15-20 -15
B-5015-2015 B50-15-2015
B75151515
Input from CARSO attitude YPR (0,0,0)
Sun directly in filters (/-14 deg ) ASTC0 (AMS x
positive) max interval10 min mean7 min
ASTC1 (AMS x negative) max interval8
min mean6 min
Sun directly in the baffle (/-80 deg ) ASTC0
max Interval 4400 min
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Lens 2
Lens 1
Baffle
ccd
electronic
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Lens 2
Lens 1
Baffle
ccd
electronic
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Baffle Support Design proposal
UPPER CONNECTION 2/3 SCREWS 0.19inches CRES A286
THERMAL INSULATOR
THERMAL INSULATOR SHIMMING PLATES
4/6 ¼ INCH SCREW CRES A286 AT THE M-STRUCTURE
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Baffle Support Design proposal
LOWER CONNECTION two set pins leave the
possibility to the baffle to thermally deform in
the axial direction without inducing stress in
the shell
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Baffle Support Design proposal
PRELIMINARY
Stress
149 MPa
(10,10,40)g
55 Hz
1 Mode
14mm
Analysis to be finalized 1) Considering all load
cases, fail safe analysis, 2)Tracker Vs
Mstructure relative displacements at Star
Trackers and Baffle fixation points due to M
structure/VC/SiT deformations (data needed from
ISATEC/Lmco) for most critical load case
10mm
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Star Tracker NEXT ACTIVITIES TEST
LEVEL 1 ASTS (Amica Star Tracker
Support) LEVEL 2 ASTC (Amica Star Tracker
Camera) LEVEL 3 BAFFLE Baffle SUPPORT (Baffle
Baffle Star Tracker Support) LEVEL 4 AST
(123) VS AMS (Amica Star Tracker versus AMS)
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Star Tracker MECHANICAL TEST
Trial assembly
1. ASTS assembly
2. ASTC Vs ASTS assembly (optics, electronics,
cooling, structure)
3. BAFFLE Vs Baffle SUPPORT AST assembly
4. AST Vs AMS a. ASTS Lower Vs Tracker b. ASTS
Upper Vs Tracker Upper Tof c. Baffle Vs M
structure d. AST Vs MLI
Vibrational test
1. ASTS, dummy mass for lens electronics
(structure first frequency and dynamic response)
2. ASTS ASTC, (structural functional test)
3. BAFFLE Vs Baffle SUPPORT (structure first
frequency and dynamic response)
4. ASTS ( ASTC) Baffle
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Star Tracker THERMAL-VACUUM TEST
1. ASTS, (structural test lens axis
deviation) Thermal vacuum test 2. ASTC,
(structural test, functional test) a.
experimental evaluation of thermal conductivity
between aluminum lens case and
glasses b. lens thermal stress c. CCD
temperature 10 thermal Cycles from sun in the
lens for 15 min to 40C worst hot, worst
cold 3. BAFFLE black anodizing aging end of
life thermo-optical properties evaluation Baffle
Vs Support Vs M structure 4. ASTS ( ASTC)
BAFFLE