TSA-HTHGA-Status-Presentation ESTEC Noordwijk 2005-02-23 Page 1
Technology Status Review
High Temperature High GainAntenna
forBepiColombo
TSA-HTHGA-Status-Presentation ESTEC Noordwijk 2005-02-23 Page 2
1. Status of Accomplishment of the current Technology Development Activity
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1.1 Objectives of TDA High Temperature High Gain Antenna
• Demonstration of critical technologies in particular
– High temperature environment
– Radiation environment• Critical technologies in this sense are:
– New materials & processes with high temperature operating capabilitiesfor the antenna reflector
– High temperature capable materials/components wrt mechanical, tribological and electrical issues for the two axes pointing mechanism
– High temperature capable materials for the RF chain (feed, waveguides, cables, transitions…)
• Very low mass antenna design
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1.2 The High Temperature High Gain AntennaMain Requirements
total mass <20 kg (1.5m); < 14 kg (1.0 m)
Mass of mobile parts < 10 kg (1.5 m)
Eigenfrequencies stowed/deployed >50 Hz / >2.5 Hz
Quasi static design loads +/- 25 g along any coordinate axis
Operational Temperature Range -150 °C < T < 250 °C
Max heat flux to s/c radiative/conductive 1000 W / 10 W
Max temperature MPO top surface 150 °C
Gain X-Band frequency X1frequency X2
>38.5 dBi (1.5m) >35 dBi (1.0m)>39.8 dBi (1.5m) >36.5 dBi (1.0m)
Gain Ka-Band frequency Ka1frequency Ka2
>50.3 dBi (1.5m) >46.5 dBi (1.0m)>50.5 dBi (1.5m) >46.7 dBi (1.0m)
Cross Polarisation < - 25 dB max rel. Peak to Peak
VSWR < - 25 dB (X and Ka-Band)
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1.3 The High Temperature High Gain Antenna
According to the TDA SOW the HTHGA consists of:
• The Antenna Reflector Assembly
• The Antenna Pointing Assembly
• The Radio Frequency Chain
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1.3.1 The Antenna Reflector Assembly
The Antenna Reflector Assembly comprises:
• The parabolic main reflector
• The hyperbolic sub reflector
• The supporting back structure
• The tripod
..\hsf-Modelle\20050218__HTHG_Antenna_BB_Assembly.hsf
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1.3.2 HTHGA DesignOverall BB Mass Budget
PART MATERIAL AMOUNT MASS [kg] FM?Main Reflector Shell C/SiC 1 2,330 3,107reflective coating Kepla 1 0,550 0,550Main Reflector Support Structure C/SiC 1 1,790 1,790Sub reflector Shell C/SiC 1 0,130 0,173reflective coating Kepla 1 0,030 0,030Sub Reflector Support Structure C/SiC 1 0,254 0,254Tripod C/SiC + Ti 1 0,719 0,719APM-Adapter-Structure C/SiC 1 0,339 0,339APM-Adapter-Flange Ti 3.7164 1 0,158 0,158Dual Feed Support 1 0,181 0,181
6,481 7,301
APM 7,467 7,467
HRM Dummies 2,223 2,160
Waveguides CFRP 0,250 0,250
Dual Feed Horn Al 1,064 1,064
Antenna BB Support Truss Steel 3,616Boom Steel 4,637 1,500Bolts & washers 0,600 0,600
26,338 20,342
Sub Total ARA
Total BB Mass
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1.4 1.4 –– Thermal AnalysisThermal AnalysisUpdates Updates sincesince last PM 4last PM 4
APM Thermal Model totally updated
Feeds Thermal Model detailed
Analysis results presented for Load Case LC1.1
Perihelion / Reflector Worst case (Hot case / Mercury in Perihelion ; Cs=14499 W/m² ; CDR LC1.1)Sub-systems worst cases are currently analysedorbital parameters : CDR status
CDR AI about planet temperature and RF loss to be included, S/C internal T° TBD by ESA
SunMercury
MPO
Earth
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1.4 Thermal Analysis1.4 Thermal AnalysisKey results Key results -- C/C/SiCSiC partsparts
- Reflector : Max. 422.7 °C (incl. +30K margin)
(Conical & Cylindrical Support Structure reduces the VF with Space)
- Sub-Reflector : Max. 413 °C (incl. +30K margin)
Calculated Temperatures w/o MARGINS
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1.4 Thermal Analysis1.4 Thermal AnalysisKey Results Key Results -- FeedsFeeds
- Feeds : Max. 213.5 °C (incl. +30K margin)
- The thermal design of the reflector rear area has been improved to reduce the feeds max Temp. but not enough to allow the use of Aluminium w/o risks : Structural checks and material change have to be discussed
-Sheldahl : 350°C for sunshield must be acceptable, anyway, sunshield improvement TBD
-First results of the WC analysis show a significant increase of the max. Temperatures
Calculated Temperatures w/o MARGINS
Spec -30K margin
Spec (either max allowable material temperature or equipment spec)
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Rotary Joints : Max. 180.0°C Clamp ring : Max.178.1°C
APM Bearings : Max. 178.0°C Crown wheel : Max. 175.1°C
Stator/rotor : Max. 178.7°C Motors : Max. 243.6°C
APM model update allows a fine check of the different APM components with different Max. allowable Temperatures. ( all temperatures incl. +30K Margin)
1.4 Thermal Analysis 1.4 Thermal Analysis Key results Key results -- APMAPM
Calculated Temperatures w/o MARGINS
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1.4 1.4 –– Temperature evolution since last PMTemperature evolution since last PM
Element / Tmax consolidated (°C) CDR PM4 Actual Max. Spec Temp. evolution
422.7 N/A
N/A
N/A
N/A
TBD/Alu
290/400
N/A
N/A
250
240
300
240
240
200
417
=
=
=
300
339.1
213.7
377.2
209.2
146.4
175
180
243.6
176.5
178.7
178.1
Remark
Reflector 360.2 396.3 Reflector Rear face partly covered with MLI + CSS reduces VF with Deep Space
Sub-Reflector 398.1 406.7 Strong VF with Reflector
Conical support structure 319.3 Isolated from Reflector with MLI
Cylindrical support structure 320.2 Conductively coupled to warm reflector
Dual Feeds 235.6 270 Thermal design optimized / isolated from reflector
Sunshield 363.4 370.0 VF with Reflector and Sub-Reflector
APM Bearings
APM Rotor/Stator
WG 200.6 205.6
Lower Boom 162.2 161.4 New APM model with coherent internal dissipations distribution
APM Flange 176.2 175.1
RJ 183.9 185.9
Actuators 216.6 217 New APM model with coherent internal dissipations distribution
APM parts
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1.5 Dynamic Analysis – Natural Modes
1st Natural Mode: 53.8 Hz7% Margin to required 50 Hz
5th Natural Mode: 70 Hz
First Reflector Mode
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1.6 Thermal Distortion Analysis ResultsBest Fit Surface Errors
LoadcaseCorrection of rigid
body motionCorrection of rigid
body motion
RMS [µm] RMS [µm]focus shift
[mm] RMS [µm] RMS [µm]focus shift
[mm]
T750s - cold Case (CDR LC12) 26.49 12.48 -0.086 21.27 21.22 -0.009
T5500s - hot Case (CDR LC13) 25.65 25.25 0.027 40.00 36.63 0.069
T7000s - Gradient 29.38 28.11 -0.026
CDR DesignNew Design
no Analysis performed
Correction of rigid body motion and focal length
Correction of rigid body motion and focal length
ConclusionThe thermo-elastic deformations of the new design are smaller than those ofthe design of CDR status.
• Hot Case: T= 5500 s (LC13 in CDR documents)• Cold Case: T= 750 s (LC12 in CDR documents)• Maximum gradient: T= 7000 s (no CDR loadcase)• Antenna is 125 degree tilted (Hot Case configuration)
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1.7 Pointing Analysis Antenna Modeling/results
• Feed System:- located at nominal position- 12dB Taper at sub reflector edge
7.15 GHzcase theta [°] phi [°] amplitude [dB] phase [°] path difference [mm]nominal 0,0000 0,0000 35,07 6,50 0,0000T750s 0,0681 -34,9523 35,06 6,40 0,0117T5500s 0,0685 -55,1856 35,05 3,60 0,3380T7000s 0,0684 -52,3502 35,05 4,30 0,2564
Position of Maximum
34.8 GHzcase theta [°] phi [°] amplitude [dB] phase [°] path difference [mm]nominal 0,0000 0,0000 49,29 -94,30 0,0000T750s 0,0684 -35,7747 49,26 -94,30 0,0000T5500s 0,0687 -55,8552 49,23 -108,20 0,3329T7000s 0,0677 -53,9836 49,20 -104,60 0,2466
Position of Maximum
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1.8 ARA BB Manufacturing Status
• Laminating moulds/tools for main and sub reflectors inhouse available
• Lay-up programming and program testing for both reflectors completed
• Lay-up of both reflector shells completed
• Green body curing of both reflector shells completed
• Pyrolysation pending (tooling definition& procurement, availabilty of facility)
• Manufacturing of cone, inner cylinder and tripod tubes planned for March
• ARA assembly planned for May
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1.8 ARA BB Manufacturing Status Sub Reflector Shell Lay-up
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1.8 ARA BB Manufacturing Status Main Reflector Shell Lay-up
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1.9 Materials & Process Sample Test Program
Thermal Cyclingin Vacuum
at ARCS
Radiation Testwith protons
at PSI
Radiation Testwith VUVat ESTEC
Life / Degradation Tests
Mechanical Tests, BOLMech. Strength
(tension, shear, ILS)Elastic Prop.
Radio Frequency, BOLReflectivityPolarisation
Optical Properties, BOLAbsorptionEmission
Thermal Tests, BOLCTECTCCp
Chemical Surface Analysis,BOLSEM
Material Characterization at Begin of Life
Mechanical Tests, EOLMech. Strength
(tension, shear, ILS)Elastic Prop.
Radio Frequency, EOLReflectivityPolarisation
Optical Properties, EOLAbsorptionEmission
Thermal Tests, EOLCTECTCCp
Chemical Surface Analysis,EOLSEM
Material Characterization at End of Life
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1.10 ARA Coating Development
• Goal
– Closed functional surface coating with good bonding on the C/SiC reflector material.
• Targeted Coating System:
– Highly RF-reflecting metallic sub-layer
– Low alpha/epsilon thermal top layer with excellent resistance against harsh Mercury environment. 10µm Ni + 10µm Cu + 40µm (Al+Al2O3)-Gradient Layer
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1.10 ARA Coating DevelopmentKepla Coat
C/SiC-Substrate
Kepla-Coat Cu-layer Ni-layer
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2. The Antenna Pointing Assembly
The Antenna Pointing Assembly consists of:
• Pointing Mechanism Azimuth stage
• Pointing Mechanism Elevation stage
• Rotary joint for X-Band and Ka-Band
• Hold-down and release mechanisms
HTS-Presentation TSR.ppt
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3. The Radio Frequency Chain
The Radio Frequency Chain consists of
• The Dual Band Feed Horn
• The X-Band and Ka-Band waveguides
RYMSA-TSR.ppt
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4. What will we have after the end of the study?
• Principle of the antenna structural design demonstrated:
– BB model manufactured
– BB model vibration tested
– Thermal distortion verified by combination of material tests, thermal distortion measurement in reduced temperature range and analytical prediction
– Mechanism BB tested in reduced environment
– Feed horn tested in reduced environment
It will have been demonstrated that BepiColombo will have an HTHGA. With the current knowledge there is show stopper but there is still additional development work to be done!
NO
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5. Critical Technology Items not covered by TDA Identification of Delta Development Needs
5.1 High Temperature CFRP Waveguides
5.2 High Temperature Joining/Mating Techniques for C/SiC
5.3 C/SiC Reflector Manufacturing Experience Build Up
5.4 C/SiC Coating Refinement & Process Adaptation
5.5 HT-Feed (Material Change)
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5.1 High Temperature CFRP Waveguides Development Needs
• Composite Technology• Plating Technology• Soldering• Manufacturing Technology
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5.2 High Temperature Joining/Mating Techniques for C/SiC
• development of HT capable ceramic bonding technique
• Mechanical mating techniques (screws, rivets)
• Tests on sample level
• Component level tests
• Establishment of the joining process
• Establishment of design guidelines
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5.3 C/SiC Reflector Manufacturing Experience Build Up
There is currently no reliable experience available with respectto high precision long fibre C/SiC antenna structures. For designing the production tools a data base of the process inherent deformations due to polymer green body curing and pyrolization needs to be established.
A programme needs to be set up to determine the material shrinkage and to derive the design and process guidelines for the moulds.
The fulfilment of this task will require to manufacture a numberof full scale reflector facesheets, to convert them into ceramic, to measure the surface error, correct the tools, manufacture the next one, measure the surface, correct the tool,..... (hopefully not until eternity).
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5.4 C/SiC Coating Refinement & Process Adaptation
• The principle of the coating has been demonstrated
• The roughness of the surface coating needs to be improved
• The coating process needs to be demonstrated on full scale flat plates and reflector facesheets
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5.5 HT-Feed (Material Change)
• The expected temperatures of the dual feed horn may require a change of the material from Aluminium to a suitable alternative
- Identification of alternative materials
- Design adaptation
- Identification of critical manufacturing processes
- Manufacturing of a HT dual feed horn
- HT dual feed horn RF test