PHOTONICALLY WIRED SPACECRAFT PANELS AN ECONOMIC ANALYSIS AND DEMONSTRATOR FOR TELECOMMUNICATION SATELLITES

Transcription

1 Philipp Putzer , Biarritz (FR) PHOTONICALLY WIRED SPACECRAFT PANELS AN ECONOMIC ANALYSIS AND DEMONSTRATOR FOR TELECOMMUNICATION SATELLITES

2 Photonically Wired Spacecraft Panels (PhWP) Agenda Project Goals Introduction to FBG Sensors Sensor Types within a Telecommunication Satellite Panel Demonstrator and Selected Components Mass Savings and AIT Time Effort Acknowledgment Seite 2

3 Project Goals 1) Demonstrate the functionality with components and processes which can be further extended to space missions. 2) The designed breadboard shall be able to sense temperatures at multiple positions with FBG sensors. 3) Mass savings and lower AIT time shall be demonstrated. For this a state-ofthe art (SOA) telecommunication satellite is analysed and the mass savings are estimated. 4) An estimation of AIT time will be carried out for both systems to estimate the overall savings. 5) The demonstrator shall be tested against local temperature variations and the full assembled and connected system will be tested against vibration. Seite 3

4 Introduction to FBG Sensors Fiber Bragg Grating (FBG) Reflection-Spectra Iin λ λ1 λ2 λ3 λ4 Itrans FBG 1 FBG 2 FBG 3 FBG 4 Iref Sensor fiber λ1 λ2 λ3 λ4 λ λ1 λ2 λ3 λ4 FBG (~1550nm) is written directly in fiber Strain and temperature measurement λ Strain Sensitivity Temperature Sensitivity Information encoded in wavelength not in amplitude Multiple FBGs with different Bragg wavelength in a single fiber 4

5 => Introduction to FBG Sensors Temperature Sensitivtiy 0.4 FBG at 26 C FBG at 46 C Characteristic FBG Wavelength Tuning Curve Photodiode Voltage [V] ragg ~ 224 pm d /dt ~ 11.2 pm/ C Bragg Wavelength λb λ B2 λ B1 ΔλB/ΔT (10 ± 2) pm/ C ΔT Δλ B T 1 Wavelength [nm] Temperature encoded in wavelength position not in amplitude (!) T 2 Temperature T Spectra shifted to the right for positive temperature shift Temperature sensitivity of pure grating here 11.2pm/ C Curve is nonlinear and depends on transducer and mounting (see later) 5

6 Introduction to FBG Sensors Measurements with Birefringent FBGs Bragg shift depends on Temperature AND strain λpm = f(t) λ1 = f(t, ε ) λ2 = f(t, ε ) Only temperature or strain information wanted: Mechanical decoupling: Current baseline Using PM FBGs Source: Interrogation and Mitigation of Polarization Effects for Standard and Birefringent FBGs, S. K. Ibrahim SPIE DCS 2016 FBG is measured with two polarization states Temperature information encoded in wavelength difference of both peaks (λpm) Not todays topic 6

7 Possible Sensors Types for Replacement Possible Sensors Types for Replacement Signal type Can be replaced? Should be replaced Analog Signal Monitor (ASM) Temperature Sensor Monitor (TSM) Potentially yes Seen critical due to performance degradation Yes, with FBG Sensors. NO YES Resistor Monitor (RSM) Not possible. NO Bi-Level Switch Monitor Not directly, optical switch needed, not economic NO Current or Voltage Sensing Potentially yes, but seen not economic NO High-Power Commands (HPC) Data transmission Potentially yes, changes in equipment necessary Potentially yes, changes in equipment necessary YES YES For high speed datalinks or highly sensitive date lines 7

8 Possible Sensors Types for Replacement Number of Sensors Signal type Number of Lines Comment Temperature Sensor Monitor (TSM) ~ 500 High-Power Commands (HPC) ~ 2000 Will not be demonstrated in BB Data transmission ~ 20 Depending on mission, for telecommunication satellites mostly not necessary. SmallGEO satellite taken as reference High number of TSM and HPC signals necessary Data transmission more interesting for scientific missions (high datarate) or military applications (no EMI radiation, security aspects) 8

9 Panel Demonstrator Component Selection Component Selection TRL Comment Temperature Sensor Technology Fiber-Optical Connectors FBG written by fs-ir laser 6+ Used also in commercial systems and technology demonstrators Glenair GFR series 6 MIL-STD tested multipole connector Transducer In house designed 5 Needed for strain decoupling Patchcord Cable STFOC Non Kink 1.65mm 6 Internal Cables Pure-silica core fiber in PTFE buffer 6+ Used in NASA and submarine applications. For protection of the 250um thin fibers during integration and assembly. Remarks to connector: Multipole necessary for economic solution (For BB 8 poles used) 9

10 Panel Demonstrator Mechanical Transducer for Decoupling 22mm x 12mm x 3mm Needed for strain decoupling Blue: Pure FBG glued to satellite panel with plate deflection. Strong influence Red: Same experiment but with transducer, Bragg wavelength mostly unaffected by strain 10

11 Panel Demonstrator Measurement Results of Sensor Calibration Sensor calibration performed with FAZ I4 Interrogator (using gas cell as absolute reference) 10 temperature cycles (approx. -10 C to 100 C) with 38 steps (steady states) up/down 11

12 Panel Demonstrator Measurement Results of Sensor Calibration Temperature steady states fitted with 2 nd order polynomial FBG sensitivity curve Temperature deviation w.r.t. fit sensor accuracy Sensor burn-in required (first five cycles) Accuracy optimization by considering polarization mitigation 12

13 Panel Demonstrator Panel Design 3 panels designed Panel 3 J30 P30 P20 J20 Interconnected with 8 pole fiber patchcords P31 J31 Panel 2 J21 In total 40 FBG sensors implemented J11 P11 P21 4 strings of FBG sensors Panel 1 2 additional lines for data communication J10 P10 All fibers implemented inside satellite panel 13

14 Mass Savings and AIT Time Effort Mass Savings and AIT Time Effort Parameter Electrical Fiber-Optical Benefit Factor Mass AIT Time Mass AIT Time High Power Com. (HPC) 224 kg n/a 37.7 kg n/a 5.9 (mass) Temp. Sensing (TSM) 16 kg 1.25 h/sensor 2.6 kg 55 min/sensor 6.2 (mass) 1.4 (time) Lot of mass can be saved for HPC harness Also for the sensing harness mass savings are possible (500 sensors taken as reference) Time for implementation in panel estimated, AIT phase currently ongoing 14

15 Acknowledgment The authors want to thank ESA for funding this activity under the framework of ARTES 5.1 ( /14/NL/AD) Special thanks are addressed to FAZ-Technologies (Ireland) for rental of the I4 FBG interrogator for the test campaign. Philipp Putzer Fiber Based Optical Frequency Comb Technical Challenge for Space Applications / Seite 15