Herschel Industrial Briefing Meeting

Transcription

1 Herschel Industrial Briefing Meeting F. Reuss HP-2-ASED-HO-0007

2 Architecture and Main Design Features Introduction - Herschel is based on the very successful Infrared Space Observatory (ISO) - Existing ISO QM - refurbished/modified - forms the Engineering Qualification Model (EQM) for Herschel Cryogenic test environment for instruments reduce risk for the Herschel particular development aspects - A Proto Flight Model (PFM) approach is foreseen for Herschel Subjected to environmental qualification / acceptance testing 2 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

3 Herschel Procurement Items The following procurement items are to be issued in the coming months: Herschel Support Structures SVM Thermal Shield PLM External MLI Thermal Shields PLM Internal MLI Optical Bench Assembly Mass and Thermal Dummies He System Tubing LOU Alignment Camera HIFI Waveguide Assembly 3 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

4 Herschel PLM Support Structures covers all major structural parts on the exterior of the Cryostat, i.e. PLM/SVM interface struts Sunshield and sunshade support struts Local oscillator unit (LOU) support structure Telescope mounting structure Sunshade Telescope Telescope Mounting Structure LOU Cryostat PLM/SVM Struts Sunshield SVM Thermal Shield Sevice Module 4 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

5 Herschel PLM Support Structures (2) PLM/SVM Interface Struts: No. of struts: 24 mount Herschel payload module on the service module - cold CVV (70 K) to warm SVM (300 K) -> thermal isolation to be optimised minimise weight 5 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

6 Herschel PLM Support Structures (3) Sunshield and Sunshade Support Struts No. of struts: 12 Support sunshield and sunshade on SVM/CVV Struts from warm sunshield to warm SVM (4): high mechanical loads Struts from warm sunshield to cold CVV (4): thermal isolation required Struts from warm sunshade to cold CVV (4): thermal isolation required minimise weight Note: Panels, stiffening ribs and brackets on panel side, little SSH/SVM and SSH/SSD struts are not part of HSS support struts 6 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

7 Herschel PLM Support Structures (4) LOU Support Structure: 8 struts & 1 support frame (I/F to LOU) provide positional stable interface (0.1 mm inplane tolerances) for the LOU under the following orbital conditions - shrinkage of CVV I/F points by 4/ temp. change of CVV I/F from RT to 60 K - temp. change of LOU I/F from RT to 150 K - pressure release from 1.05 bar to 0 bar - humidity release 7 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

8 Herschel PLM Support Structures (5) cryostat baffle hexagonal frame CVV/TMS struts (6) TMS/CB struts (6) Telescope Mounting Structure (TMS): 6 struts between CVV and a hexagonal frame & 6 struts between frame and cryostat baffle support weight of telescope (300 kg) provide thermal isolation CVV/telescope provide plane and shrinkage-free frame/telescope interface (0.08 mm planarity required) for the telescope under the conditions of 4 mm radial shrinkage of CVV I/F points minimise weight dedicated MGSE needed to achieve frame planarity when TMS is integrated on CVV 8 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

9 Herschel PLM Support Structures (7) Deliverables: Delivery dates: Qualification Models April LOU Support Structure (1 strut) - HSS Support Struts (1 axial + 1 lateral) - PLM/SVM I/F (1 strut) - TMS (1 TMS/CVV + 1 TMS/CB strut) EQM May LOU Support Structure (struts + baseplate) Flight Model January LOU Support Structure - HSS Support Struts - PLM/SVM I/F - TMS 9 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

10 Herschel SVM Thermal Shield SVM thermal shield is mounted on top of the SVM Sunshade function: to protect the cold CVV from the hot SVM against radiation It is tilted 5 degree towards the SVM: Telescope Telescope Mounting Structure LOU Cryostat PLM/SVM Struts SVM Thermal Shield Sunshield that way it works as a so-called V-groove, reflecting heat coming from the SVM into deep space Sevice Module 10 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

11 Herschel SVM Thermal Shield (2) 2 panels (split in 2 parts for easier integration) & 5 bi-pods and 4 vertical struts Main design driver - minimise SVM thermal shield -X side emissivity (ε < 0.04) SVM will remain at RT in space The SVM shield temperature will drop to ~ 110 K: - Minimise SVM thermal shield temperature through thermal decoupling of SVM from the SVM thermal shield via its mounting struts 11 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

12 Herschel SVM Thermal Shield (3) Deliverables: Qualification Model SVM Thermal Shield Fixation (1 bi-pod strut + 1 vertical strut) Protoflight Model SVM Thermal Shield and Fixations Delivery Dates: QM and PFM February HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

13 Herschel PLM External MLI Cryostat Baffle MLI LOU Radiators CVV Main Radiator -Y Radiator Sunshield MLI Sunshade MLI CVV Upper Bulkhead MLI +Y Radiator -Z Radiator CVV Lower Bulkhead MLI SVM Thermal Shield MLI Main functions/features: Thermal Insulation of - sunshade/ sunshield - CVV sunshield-oriented side - CVV upper bulkhead - CVV lower bulkhead - CVV ±Y radiator rear sides - Cryostat Baffle - SVM Thermal Shield - LOU-box - BOLA-box - Some struts External layer low emissive (ε < 0.045) ==> Minimising radiative heat exchange 13 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

14 Herschel PLM External MLI (2) Driving Requirements: Excellent thermal performance at cryogenic temperatures (down to 50 K) Excellent workmanship (overlaps, sealing of edges & penetrations, etc) External surfaces low-emissive (ε < 0.045) ==> eventually goldized ISO-heritage not sufficient design to be optimised w.r.t. Herschel Notable/Critical Aspects: Many penetrations (struts, ribs, harness) to be closed with adequate overlapping/closing techniques Some restricted areas need SSM foils as external layer (incidentally exposed to sun in contingency cases) Qualification Tests on S/C level with PFM blankets Acceptance Tests on S/C level with same PFM blankets ==> no STM-blankets ==> blankets to be refurbished, evtl. repaired after STM TB/TV test good co-operation with the main integration/assembly teams 14 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

15 Herschel PLM External MLI (3) Deliverables: 11 H/W items (w.r.t. product tree) for PFM (consisting of several blankets) sample blankets Delivery dates: CVV blankets March 2004 Sunshield/Sunshade blankets July HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

16 Herschel PLM Thermal Shields Main functions/features: Mechanical support for the Internal MLI inside the CVV Allow the cooling of the thermal shields by the Helium in the vent lines Covering the entire inner surface of the CVV 16 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

17 Herschel PLM Thermal Shields (2) Driving Requirements: thermal coupling across the three shields Minimum mass Notable/Critical Aspects: Welding of the Helium vent lines on the Thermal Shields Forming of the dome parts of the upper and lower shields 17 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

18 Herschel PLM Thermal Shields (3) Deliverables: one PFM, completely new designed for Herschel comprising: - Lower Bulkhead Thermal Shields - Cylinder Thermal Shields - Upper Bulkhead Thermal Shields EQM parts, to be integrated to the existing EQM shields: - Upper Bulkhead Thermal Shields - Intermediate Cylinder Thermal Shields Delivery dates: EQM April 2003 PFM August HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

19 Herschel PLM Internal MLI Optical Bench and beam pattern shield with MLI 3 Radiation Shields with MLI Cryostat Vacuum Vessel (CVV) Helium II Tank (HTT) with MLI Helium I Tank (HOT) with MLI Main functions/features: Thermal Insulation of HTT, HOT, OBA, Thermal Shields and Filling Port within CVV in high vacuum ==> Minimising parasitic heat flow into tanks ==> driving He mass flow rate Enabling mission lifetime of 3.5 years 19 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

20 Herschel PLM Internal MLI (2) Driving Requirements: Excellent thermal performance at cryogenic temperatures (down to 1.7K) Excellent workmanship (overlaps, sealing of edges & penetrations, etc) Cleanroom class 100 at delivery Integration in cleanroom class 100 Pre-baking of components prior to blanket composition ISO-heritage not sufficient design to be optimised w.r.t. Herschel Notable/critical Aspects: Qualification Tests on S/C level with PFM blankets Acceptance Tests on S/C level with same PFM blankets ==> no STM-blankets good co-operation with the main integration/assembly teams 20 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

21 Herschel PLM Internal MLI (3) Deliverables: 5 H/W items for PFM (consisting of several blankets) 2 H/W items for EQM (consisting of several blankets), i. e. only 3 Radiation Shield blankets for upper bulkhead, Optical bench and beam pattern shield MLI sample blankets Delivery dates: EQM-blankets June 2003 PFM blankets September HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

22 Herschel Optical Bench Assembly (OBA) Main Features shall provide through the Optical Bench Plate (OBP) a solid and alignment stable support for the Scientific Instruments (FPU s) within the Herschel cryogenic environment (Cool down from room temperature to 10K), shall protect the FPU s from straylight, through the Optical Bench Shield (OBS) and provide light tightness of all feedthroughs, the Optical Bench Thermal Links (OBTL) connect the FPU s and the Helium Two Tank (HTT) for cooling of the FPU s. the OBP shall carry the Optical Bench Helium Cooling Line (OBHCL) used to cool down the FPU s, which are thermally connected via thermal straps to OBHCL (level 1), to cool down the directly connected OBP (level 2) and the SPIRE-JFET (level 3). 22 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

23 Herschel Optical Bench Assembly (OBA) (2) OBA Bottem View OBA, View w/o Shield OBHCL Support OBHCL Level 1 LOU Baffle Flexible Thermal Links Blade Bracket I/F OBHCL Level 2 Harness Feedthrough Fixed Thermal Links OBA Top VIEW Entrance Baffle SPIRE OBS PACS HIFI OBP OBA Dimensions: Diameter 1630 mm Height w/o OBTL 630 mm 23 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

24 Herschel Optical Bench Assembly (OBA) (3) OBA Main Design Drivers Firm stability due to cooling down from room temperature to 10K Eigenfrequency/stiffness requirement of OBP, f > 70 Hz out of plane Strength compatibility against handling-, transportation-, launch and in orbit loads Straylight constraints (light tightness) Heat tranfer constraints (from HTT to FPU s and OBHCL to FPU s, OBP and JFET s) Delta-p compatibility 24 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

25 Herschel Optical Bench Assembly (OBA) (4) OBA Items Optical Bench Plate (OBP) Optical Bench Shield (OBS) Optical Bench Helium Cooling Loop (OBHCL) Optical Bench Thermal Links (OBTL) - Level 0, direct connection from HTT to Instruments - Level 1, connection OBHCL to Instruments - Level 2, connection OBHCL to OBP - Level 3, connection OBHCL to SPIRE-JFET Fasteners for mounting of OBS and OBHCL to OBP and I/F Bolts to the SFW Mass Dummies Instrument Units mounted on the OBP Optical Bench Instrumentation Interfaces Scientific Instruments and Cryostat Instrumentation Harness Interfaces 25 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

26 Herschel Optical Bench Assembly (OBA) (5) Deliverables: Optical Bench Assembly EQM Optical Bench Assembly PFM FS (refurbished EQM OBP) Spare material Specific Handling Devices FPU & JFET Mass Dummies Shipping and Storage Container Cover for light tight closure Delivery Dates: Optical Bench Assembly EQM September 2003 Optical Bench Asembly PFM December 2003 FS (refurbished OBP-EQM) 2004 to HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

27 Herschel PLM Mass & Thermal Dummies (MTD) MTDs replace the Flight Instrument Units during ground tests OBA, View w/o Shield Similarity to real flight instruments with respect to mechanical, thermal and electrical properties OBHCL Support OBHCL Level 1 OBHCL Level 2 Harness Feedthrough Fixed Thermal Links Flexible Thermal Links - Mechanical interfaces (Mass, CoG, MoI, dimensions, shape, I/F mounting geometry and technique) - Thermal behaviour with emphasis on cryogenic aspects (thermal radiation and conductance, cooling straps, MLI, simulation of heat dissipation) - Electrical interfaces (flight quality connectors to allow utilisation of the flight harness) 27 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

28 Herschel PLM Mass & Thermal Dummies (MTD) (2) Deliverables: HIFI FPU HIFI LOU SPIRE FPU SPIRE JFET Spectrometer & Photometer PACS FPU PACS BOLA Telescope Thermal Dummy & Mechanical Dummy Delivery dates: internal MTDs August 2003 external (Telescope Dummies) MTDs October HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

29 Herschel PLM Helium System Tubing Main Function: - allow the Helium flow from the tanks to the instruments on the Optical Bench and thermal shields in order to bring the instruments to an operating temperature of a few K - Tubing connecting the filling port for LHe to the tank up the Helium exhaust to space in orbit/to the He pumping system on ground Helium Two Tank (HTT) tubing Helium One Tank (HOT) tubing CVV External Tubing 29 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

30 Herschel PLM Helium System Tubing (2) Driving Requirements: - LHe II-tightness of internal tubing 1 * 10-9 mbar * l / sec - He-tightness of external tubing 1 * 10-6 mbar * l / sec - Low -p of the branch from the phase separator to the nozzles - Welding of the tubes by means of TIG or orbital welding (partly in cleanroom class 100 ) 30 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

31 Herschel PLM Helium System Tubing (3) Model Philosophy: - FM manufactured on Mock-ups Mock-ups: "HTT outer surface "HOT outer surface "CVV outer surface of cylindrical part - Qualification of the Tube welding parameters TIG (WIG) welding Orbital welding Deliverables: - FM Internal and External Tubing - Mock-ups - Spare Parts (Tubes; fittings; bellows) - Welded QM samples 31 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

32 Herschel PLM Helium System Tubing (4) Delivery Dates : - HTT- Tubing with mock-up May HOT- Tubing with mock-up July External -Tubing with mock-up January HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

33 Herschel PLM LOU Alignment Camera Main functions/features: LOU w.r.t. HIFI alignment check using the LOU Alignment Camera (only one camera shown Measurement of LOU w.r.t. HIFI alignment inside TB/TV chamber at appr. 90 K (CVV temperature) and CVV shrinkage --> confirmation of mathematical model Alignment check after evacuation and cool down Alignment check before and after environmental testing Measurement of LOU w.r.t. HIFI FPU alignment at ambient 33 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

34 Herschel PLM LOU Alignment Camera (2) Main Features: Alignment checker to be performed inside TB/TV chamber at appr. 90 K Camera System has to measure rotation and translation - Rot (y) to be measured using two cameras Accuracy Requirements - x = + 0,1 mm, y = + 0,25 mm, z = + 0,1 mm - Rotation = + 10 aresec about x, y, z axis Delivery Date: November HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

35 Herschel PLM HIFI Waveguide Assembly Main functions and features - The waveguide assembly provides the RF signal link between the HIFI Local Oscillator Source Unit (LSU) accommodated within the SVM and the HIFI Local Oscillator Unit (LOU) mounted on the outside of the CVV - The waveguide assembly consists of 14 waveguide runs, each dedicated to a specific signal band 35 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

36 Herschel PLM HIFI Waveguide Assembly (2) Driving Requirements - Operation frequency range between 23.7 and 35.3 GHz - Insertion loss less than 2 db - Low thermal conductance to minimise heat flux from SVM to LOU (LOU operating temperature is about 120 K) need of specific material as e. g. stainless steel - Mechanical eigenfrequency above 120 Hz need of specific stiffening due relatively long distance between adjacent supports of up to 550 mm due to CVV constraints - Mechanical design shall cope with displacements of interface points in the order of 5 mm due to thermal shrinkage of the CVV need of flexible waveguide sections 36 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

37 Herschel PLM HIFI Waveguide Assembly (3) Model philosophy and deliverables - PFM - Spare samples (reduced spares for recurring parts) - Note: for the Herschel EQM programme commercial standard aluminium waveguides are foreseen (only 2 chains are needed) Delivery dates - Need date for PFM: March HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

38 Herschel PLM HIFI Optical Window Assemblies Main functions and features - The seven central windows are used to feed the quasi-optical signals from the HIFI LOU into the CVV to the HIFI FPU mixers - The two outer windows will be used to verify the alignment during on-ground system tests. They will be closed by covers prior to launch - The windows shall air tightly close the cryostat during the spacecraft onground testing, when the CVV is evacuated 38 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

39 Herschel PLM HIFI Optical Window Assemblies (2) Driving Requirements - Operation frequency range between 480 and 1910 GHz - Transmission of greater than 80 % at end of life condition within the specified frequency ranges - Free aperture with a diameter of >34 mm in xz-plane very little space between windows (<16 mm) for window frames and sealing - Precautions to prevent standing waves - Leak rate less than 10-8 mbar l/sec He per window assembly at a pressure difference of 1.05 bar between front and rear side of the windows - The window assemblies shall be designed to withstand a pressure difference of 4.0 bar between the rear and front side of the windows without rupture (helium tank failure case) 39 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

40 Herschel PLM HIFI Optical Window Assemblies (3) Model philosophy and deliverables - QM - 2 sets of FM (one for Herschel EQM and one for Herschel STM/PFM - Spare samples (reduced spares for recurring parts) - Note: QM cannot be used for Herschel EQM due to on-ground safety reasons Delivery dates: - Planned delivery date for PFM: May HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting

41 Herschel PLM Additional Items The following items are actually considered to be procured from outside to support the Geo Return obligations : EPLM Test Harness SVM Dummy CVV Radiator (tbc) 41 HP-2-ASED-HO-0007 Herschel Industrial Briefing Meeting