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SPICA / AIV&T issues Spacecraft test program & model philosophy Rev. C, Mar. 13th, 2010 by H. Matsuhara, N. Takahashi, T. Nakagawa Revised points (from Feb 19 ESA-JSAS telecon.) are indicated by red SPICA Telescope Assembly (STA) 3m-class cooled telescope Monolithic Mirror No deployable mechanism Herschel & AKARI Heritage AKARI: WFE 0.35μm, 6K (70cm) Herschel: WFE 6μm, 80K (3.5m) SPICA: WFE 0.35μm, 5K (3.5m) Ceramic material (SiC) Simple, Feasible, Reliable Smooth PSF Essential for Coronagraph STA models & proposed delivery (tentative plan) STM (Structure Thermal Model) Proposed delivery : Oct. 2012 (beginning of 3Q of FY2012) AIT plan Integrated as PLM (STM) Thermal test at cold (@Tsukuba 13m chamber) Integrated into Spacecraft (STM) Spacecraft Mechanical Environmental test & Thermal Vacuum Test FM Proposed delivery : Jan. 2017 (beginning of 4Q 2016) STA Optical Performance test at cold (1) Date & duration: 1Q of CY2017, 1-2 months Place : 6m Space Chamber in Tsukuba Space Center Configuration IOB(FM dummy)+STA(FM) Additional thermal sheild in the chamber Purposes: Optical performance evaluation of STA at <10K Multiple measurements are connected by the Stitching Method 4 STA Optical Performance test at cold (2) 2 LN2 Shroud GHe Shroud Flat-mirror STA ACF Cryo Sorption Pumps 5 Interfero meter 6 ACF 8 1 7 Gear Motor Turbo Molecular Pumps 5-axis stage Test Specimen Mount Table (with Shroud) 4 Anti-Vibration Table GHe 3 Pillar of Vacuum Vessel LN2 Independent Foundation 5 PLM Thermal Test at cold (STM and FM) Purpose Date & Duration Evaluation of PLM cooling system performances Alignment measurement between STA and FPIA with FPC? STM: April 2013 FM: Dec. 2017, ~2months Method Additional shields in the existing 13m space chamber in Tsukuba Shields are externally lifted by mechanical coolers 6 SPICA AIV&T timeline (tentative) Consistency need to be checked with Industries’ estimates !! 7 Key issues for FPI AIV&T FPI’s system-level test plan should take account of the critical issues as below: (a) FPI is cooled to <5K with J-T coolers under extremely careful Spacecraft thermal design. (b) disturbance and interference from J-T coolers and AOCS (such as RW, gyro) (c) Co-operation with FPC-G to establish the pointing stability To assure high-sensitivity (low-noise) in orbit Interferences? Alignment? (d) Co-focus among FPIs (especially MIR’s) Since STA 2ry cannot be adjusted so frequently in orbit FPI Model philosophy Cold FPIs Minimum number of Models required for the system level test (in the previous page) is: FM (Flight Model) (& its spare) STM : structure thermal model CQM : cold qualification model Warm Electronics Similar as above, except for the terminology (CQM PM (protomodel) A concern about SAFARI Warm Electronics STM : can the requested heat dissipation be simulated by a heater? Spacecraft DHS simulator(SpaceWire I/F) will be developed, and distributed hopefully before 2014 ( under discussion) STM (Structure Thermal Model) for FPIs Purposes Required Function Evaluate their mechanical (at ambient temp.) & thermal compliances at cold, in the system level (PLM or Spacecraft) Evaluate transfer function of mechanical disturbances originated from FPIs Same mechanical I/F specifications to FM Same thermal I/F specifications to FM Equipped with thermometers, acceleration sensors for measurement of I/F environmental condition Simulate mechanical disturbance according to the system operation modes Proposed Delivery Oct. 2012 : before starting of assembly of PLM(STM) for the system Mechanical & Thermal Test CQM (Cold Qualification Model) for FPIs Purposes Required Function Evaluate thermal compliance at cold with J-T(PM) cooler Evaluate susceptibility to mechanical disturbances from J-T (disturbance simulator) and AOCS simulator Evaluate electrical interferences among FPIs, J-T, AOCS Same thermal, mechanical, electrical I/F specifications to FM Equipped with detectors operable at low-temperature, with the same noise performance as that of FM Simulate heat-dissipation (load to J-Ts), mechanical disturbance according to the system operation modes Equipped with a optical image, to check the co-focus among FPIs Proposed Delivery Apr. 2015 : when the PLM(FM) is available for us to test the items in page 2. Earlier delivery enables us to feedback for the design of FM FM (Flight Model) for FPIs Purposes Required Function For on-orbit observations; for our scientific objectives, of course! After delivery and assembly to FPIA, FM will go to the “evaluation at cold” in the dedicated chamber for evaluation of interferences, co focus among FPIs Science Grade optical, noise, and sensitivity performances! Note that after the test called “FPI evaluation at cold”, longwavelength channel detectors cannot be operated (even may not be switched on??) - so how to verify its health during the long waiting time before launch/cooling in orbit? Delivery date of FM: June 2016 (August 2016 at worst) in the proposed scenario. FPI: SPICA system test plan With STM: With CQM: Mechanical Environmental test & thermal test at cold at the PLM level Mechanical Environmental test & Thermal balance test at Spacecraft level Measure disturbance at FPI from J-T cooler/AOCS Cooling compliance test with J-T (PM) most important Evaluate susceptibility to mechanical disturbances from J-T (disturbance simulator) and AOCS simulator, Co-focus is also checked to some level at cold (tbd) Evaluate electrical interferences among FPIs, J-T, AOCS in the 1st whole FM V&T in 2016 if FM is not available yet With FM FPI evaluation at cold (optical & electrical) STA optical performance test at cold Thermal test at cold at PLM level 13 FPI(CQM or FM) test config. in the 1st Whole FM V&T 1Q-2Q FY2016, checkout with FM Bus Module Electronics before assembly/integration of FM Bus System IOB FPI FPI LHe Mech. Cooler (commercial) 14 Focal Plane Instrument Assembly (FPIA) = IOB+FPI 2300 mm TOB:Telescope Optical Bench IOB: Instrument Optical Bench 15 FPI Evaluation at cold Date & Duration: Place: 6m Space Chamber at Tsukuba Space Centre (tbd) Configuration: latter half of CY2016, 1-2 months IOB(FM)+FPI(FM)+cooler(TBD – probably not necessary)+FPI warm electronics (FM) (+STA Simulator..) Purposes: With all FM FPIs together, all functional, electrical & optical performance evaluation at cold (operating temperature in orbit) as well as interference test. Optical performance will be measures with a STA simulator. 16