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Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) Instrument Preliminary Peer Review Mechanical Systems E. Stump 3/19/14.

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Presentation on theme: "Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) Instrument Preliminary Peer Review Mechanical Systems E. Stump 3/19/14."— Presentation transcript:

1 Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) Instrument Preliminary Peer Review Mechanical Systems E. Stump 3/19/14

2 2 Mechanical Systems Peer Review  MIGHTI Overview  Mechanical Driving Requirements  Mechanical Design Overview  Interfaces and Interface Control Documentation  Optics Mechanical Alignments  CBE Mass  Structure Analysis Summary  Future Design Activities Outline

3 3 Mechanical Systems Peer Review  MIGHTI is a key instrument on the NASA Class C Ionospheric CONnection Explorer (ICON) Mission headed by the Space Sciences Laboratory (SSL) at UC Berkeley (Dr. Immel, PI)  MIGHTI is a limb imager with two orthogonal fields of view measuring velocity and direction of the thermospheric wind using the atomic Oxygen red and green lines (630.0 nm & 557.7 nm) and the temperature using the molecular Oxygen atmospheric (A) band (762 nm).  ICON Spacecraft Bus Developed by Orbital  MIGHTI is based off the heritage designs of the SHIMMER instruments successfully flown on STS-112 (2002) And STPsat-1 (2007) Overview (1 of 3) MIGHTI Ahead (A) MIGHTI Behind (B) ICON 630.0nm 557.7nm 762.0nm

4 4  Camera Electronics box with an integral radiator  Calibration Lamp – Light source for calibration optics on both MIGHTIs  Two identical MIGHTI instruments, located at 90°±5°  575km Circular Low Earth Orbit  TBD Launch Vehicle – Pegasus Class (Mass Limitations)  Accelerated Schedule: MIGHTI PDR = 4/22/14 MIGHTI CDR = 11/25/14 (Tentative) MIGHTI PER = 7/9/15 (Tentative) MIGHTI Instrument Delivery to U.C. Berkeley for Integration with Other Payloads = 11/23/15 MIGHTI Overview (2 of 3)

5 5 Mechanical Systems Peer Review Mechanical System Driving Requirements (L4) NumberRequirement M-4-1The MIGHTI instrument shall be designed to operate on orbit for a minimum of 25 months M-4-2The MIGHTI instrument shall not have any consumables other than component lifetime. M-4-3The MIGHTI instrument shall be designed for a near-circular orbit with a targeted altitude of 575 km at beginning of life (BOL). M-4-20The MIGHTI instrument shall have the capability to make measurements of the Doppler shift of OI lines, of a common volume of space, at 630.0 nm and 557.7 nm from at least 2 view angles separated by 90+/-5 degrees of arc with the angles symmetric about the Observatory Y axis. M-4-80The MIGHTI instrument shall be able to perform a star observation with an angular uncertainty of 20 arcsec (3-sigma) or better. M-4-81Both MIGHTI optical units shall be capable of observing a green and red calibration line signal provided by a krypton and neon lamp respectively. M-4-100The mass of the MIGHTI instrument shall be within the allocation defined in ICN-SYS-004. M-4-103The MIGHTI baffles shall have a door that can be opened on orbit. M-4-104The MIGHTI instrument shall be designed to allow for continuous purge. M-4-120The knowledge of the angular relationship between the boresights of each MIGHTI field of view and the corresponding MIGHTI alignment cube shall comply with the ICON Alignment Plan. M-4-122The variation in the relative angular orientation of the MIGHTI boresights to the MIGHTI mounting points shall be maintained to within 16 arcsec, 3 sigma, under the thermal conditions expected on-orbit. M-4-130The MIGHTI instrument shall be designed to accommodate up to 3 total ferry flights between the WTR and ETR (assumes Pegasus). M-4-131The MIGHTI instrument shall be capable of meeting all operational requirements over > 90% of primary mission lifetime. This includes science measurements and calibration measurements.

6 6 Mechanical Systems Peer Review Mechanical System Driving Requirements (L4) NumberRequirement M-4-134The MIGHTI instrument shall have access to all radiators (hardware and FOV) required to keep instruments within their Allowable Flight Temperatures (AFTs). The MIGHTI instrument shall accommodate all radiators (hardware and FOV) required to keep the sensor portion of the instrument within its Allowable Flight Temperatures (AFTs). M-4-135The MIGHTI instrument shall accommodate survival heater and corresponding mechanical thermostats with power provided by the S/C (28 V +/-6 V) to maintain survival temperatures while the payload is off. M-4-136The MIGHTI instrument shall have heater(s), controlled by the ICP via a sensor feedback loop, to maintain the operational temperature range of the two interferometer enclosures to  0.1°C. M-4-137The MIGHTI instrument shall have heater(s), controlled by the ICP via a sensor feedback loop, and corresponding radiative surfaces to maintain the operational temperature range of the two optical benches to [  2°C]. M-4-138The MIGHTI instrument shall have thermo electric coolers, controlled by the ICP via a sensor feedback loop, and corresponding radiative surfaces to maintain the operational temperature of the two CCDs to -45°C [+0°C, -15°C]. M-4-139The MIGHTI instrument shall accommodate four temperature sensors read by the S/C bus system. One on each CCD camera head and one on each optical bench. M-4-141The MIGHTI instrument shall route independently controlled actuator power interfaces from the spacecraft for the MIGHTI-A, MIGHTI-B one-shot covers, each one capable of providing 28 V +/- 6 V @ 3 Amp. M-4-144The MIGHTI instrument shall be designed to attenuate the incoming light for stray light rejection between daytime and nighttime observations. M-4-145The MIGHTI instrument shall be designed to have two calibration light sources at wavelengths near 557.7nm and 630.0nm that can be switched independently. M-4-160The MIGHTI instrument shall be designed with alignment fiducials necessary to perform instrument alignment on the PIP. The fiducials shall be accessible for surveying equipment throughout I&T, as designated in the Payload Alignment Plan. M-4-161MIGHTI shall be designed to accommodate contamination witness plates necessary to monitor and assess contamination of the instrument.

7 7 Mechanical Systems Peer Review Mechanical System Driving Requirements (L4) NumberRequirement M-4-162All remove before flight items shall be colored red and marked with “Remove before flight!”. M-4-164At the Payload I&T phase, the measurement accuracy of the MIGHTI mass shall be ±0.2%, the center of gravity shall be ±6.4mm and the accuracy of the calculated MOI shall be ±5% M-4-165MIGHTI shall have the capability to verify electronics end-to-end after integration to the payload and the spacecraft and the launch vehicle. M-4-180Appropriate mechanical GSE to perform instrument alignment and I&T shall be designed and implemented. M-4-181Appropriate lift fixtures to support payload I&T shall be designed and implemented. M-4-183An instrument transport container capable of safely transporting and monitoring the payload shall be designed and implemented. M-4-200The MIGHTI instrument shall comply with the ICON Environmental Requirements Document, ICN-SYS-003. M-4-201MIGHTI shall be designed to meet the requirements in the Instrument Grounding Diagram. M-4-202The MIGHTI instrument shall comply with the ICON Contamination Control Plan, ICN-SMA-011. M-4-181The MIGHTI instrument shall comply with all aspects (thermal, mechanical, electrical software, data) of the MIGHTI ICD, which defines the interfaces among MIGHTI, the payload and the S/C.

8 8 Mechanical Systems Peer Review Mechanical System Driving Requirements NoCategoryDriving RequirementPre-PDR Status 1Opto-Mechanical MIGHTI Opto-Mechanical Design Requirements – SSD- SPC-MI004, Optical Components and Subassemblies Performance Specification and the MIGHTI Optical Layout, ATK-F1753 Design Complies 2Structural Launch Loads/Minimum Frequency per ICON Environmental Requirements Document – ICN-SYS-003 Quasi-Static Design Limit Load defined by NLS Option B Launch Vehicle MAC Curve, 1 st Primary Mode >100 HZ Design to be Verified by Analysis 3 Mechanical Mass - ICN-SYS-004, ICON Resource Allocation and Tracking Design to Comply 4 Mechanical Interface MIGHTI / PIP Interface - MIGHTI MICD (ATK-F1800) Complies with ICN-ICD-002 5 Mechanical Interface MIGHTI / Camera Interface – MIGHTI Camera MICD (ATK-F1733) Design to Comply 6Contamination Materials, Surface Finishes, Coatings, Vent/Purge Features and Witness Plate provisions IAW MIGHTI Contamination Control Plan Complies with ICN-SMA-011 7Electrical Grounding IAW MIGHTI Instrument Grounding DiagramDesign to Comply

9 9 Mechanical Systems Peer Review Mechanical Design – Layout – MIGHTIs on PIP MIGHTI B Camera Electronics Calibration Lamp MIGHTI A  Two identical MIGHTI instruments, located at 90°±5°  Camera Electronics box with an integral radiator  Calibration Lamp – Light source for calibration optics on both MIGHTIs X Y SC

10 10 Mechanical Systems Peer Review Mechanical Design – Layout Optical Bench Aft Optics Enclosure Entrance Pupil & Shutter Housing Heat Pipe Optics Enclosure Instrument Flexures (2) near side (2) far side Camera Baffle Assembly Stepper Motor Control Calibration Optics Camera/Heat Pipe Interface

11 11 Mechanical Systems Peer Review Mechanical Design – Layout Radiator (Camera CCD cooling) Baffle & Radiator Supports Baffle Door Door Pin Puller Calibration Cube

12 12 Mechanical Systems Peer Review Mechanical Design Aft Optics Housing w/ Entrance Pupil (A1) and First Fold Mirror A1 Shutter in Daytime 15% Position Baffle Assembly Baffle Door (closed) Optics Enclosure

13 13 Mechanical Systems Peer Review Mechanical Design – Optics Layout M1 M2 L1 Field Stop M4 L5 Beam Splitter Calibration Optics Camera L2 LYOT (A2) Stop Dichroic Wedge L4 Interferometer Oven A2 Shutter Assy L3 F1 M3

14 14 Mechanical Systems Peer Review Mechanical Design – Dimensional Layout - Instrument

15 15 Mechanical Systems Peer Review Mechanical Design – Dimensional Layout – Cal Lamp & Ebox

16 16 Mechanical Systems Peer Review Mechanical Design – Dimensional Layout - PIP

17 17 Mechanical Systems Peer Review Mechanical Design - Layout Field Of View 90° Keep Out Zone

18 18 Mechanical Systems Peer Review  Heritage ‘SHIMMER’ design concept modified to meet MIGHTI requirements  Thermally controlled aluminum enclosure (oven) to maintain 25°C±0.1°C  Supported only at center Beam Splitter cube  Interferometer contacts currently shown here are notional. Specific optic support configuration being developed to meet MIGHTI requirements  Fixed, thermally isolated interface to optical bench (other optical components align to Interferometer) Mechanical Design – Interferometer Mount/Oven Interferometer Top Plate Base Plate Thermal Isolators Fixed Top Interferometer Contacts Spring Loaded Bottom Interferometer Contacts

19 19 Mechanical Systems Peer Review Mechanical Design - Interfaces TitleICDDescriptionStatus MIGHTI MICD F1800 MIGHTI Mechanical Interface Control Drawing Complies with ICN-ICD-002, Interface Control Document, MIGHTI to Payload Preliminary Submitted to UCB Camera MICD F1733 Volume Allocation Alignment Requirements Mounting & Connector Provisions Filter Orientation In Process Optical MICD F1753 Relative Location of Optical Components in the MIGHTI Instrument In Process

20 20 Mechanical Systems Peer Review  Instrument to PIP (4) Titanium Flexures from the Optical Bench to the PIP (2”x2” interface pad) (4) NAS1351 10-32UNF-3A fasteners per flexure to PIP and to Optical Bench Alignment Pin & Slot – (2) Ø.12500 MS9390 Pins Flexures attach to the PIP (located w/ GSE plate) then MIGHTI attach to flexures due to flexure/PIP fastener accessibility Flexure interface to be shimmed as required to minimize gaps and integration assembly loads. Mechanical Design – Interface to PIP

21 21 Mechanical Systems Peer Review  Calibration Lamp to PIP (1) Titanium Flexure for structural and thermal isolation from the PIP Flexure design currently being optimized to meet requirements  Camera Electronics Box to PIP (1) Titanium Flexure for structural and thermal isolation from the PIP Flexure design currently being optimized to meet requirements Mechanical Design – Interface to PIP

22 22 Mechanical Systems Peer Review Mechanical Design – Heat Pipe to Camera  1.75” x 2.75” contact area between heat pipe flange and camera interface  Additional thermal mass required – implemented as a beryllium clamp/saddle  Heat Pipe clamped (thermally isolated) to the optical bench to minimize loads on camera interface Thermal contact area Heat Pipe to TEC Hot Side Beryllium Clamp/Saddle Heat Pipe Clamp Assy Thermally isolated from bench

23 23 Mechanical Systems Peer Review  Optics required to couple the external Calibration Lamp fiber optics to the internal Beam Splitter Cube Assembly  Plan to slightly extend optical bench and incorporate a fiberoptic bulkhead connector, a small fold mirror and an off axis parabola, utilizing the structure of the bench as the enclosure  Need to work through the design and structural impacts of embedded design. Contingency plan to keep optics outside of bench structure Mechanical Design – Calibration Optics (external) OAP Fold Mirror Cover / Mount Plate Fiberoptic Bulkhead Beam Splitter Assembly Fold Optics Contingency Location

24 24 Mechanical Systems Peer Review Detailed Design - Structures Optical Bench Instrument Flexures Aft Optics Enclosure Entrance Pupil/ Shutter Housing Baffle Enclosure & Baffles Radiator Mounts Optical Enclosure & Cover  Aluminum 6061-T6 Optical Bench  Black Anodize (MIL-A-8625 Type II, Class 2)  Select external areas with thermal control coating Optical Enclosure  Black Anodize Aft Optics Enclosure  Black Anodize Entrance Pupil & Shutter Housing  Black Anodize Baffle Enclosure  Black Anodize Baffles  Z306 Black Paint  Titanium TI-6Al-4V Instrument Flexures Radiator/Baffle Mount Radiator Flexures Baffle/Radiator Supports Radiator Mount Radiator Baffle/Radiator Support Radiator Flexure

25 25 Mechanical Systems Peer Review  Optical Bench will be mounted vertically to an optical table  General assembly/alignment approach is fixed baffle axis, fixed Field Stop and fixed Interferometer. All other components shimmed and/or adjusted at assembly to complete optical path  The Optics MICD defines the nominal locations of the components and the Optical Components and Subassemblies Performance Specification, SSD-SPC-MI004, defines the required nominal adjustment for the different components  Various GSE - pin holes and diffusers provided for use during alignment  Lens Mounts slotted for focus adjustment (+/-X) with the use of a GSE guide rail positioned visually within the mounting tolerances (≥.005”)  Mirror Mounts tip/tilt/translate via shims Optics Mechanical Alignment Optical TableGSE Bench Supports Instrument Coordinates GSE Focus Rail (typ)

26 26 Mechanical Systems Peer Review Optical Alignment Budget ComponentLocation/mount Shimming (.0005" resolution) Adjust M1 Assyfold mirror housing side wall.010" - tip/tilt - about 'Y'N/A M2 Assyoptical bench.010" - tip/tilt/heightN/A M3 Assy'L' Bracket to optical bench.020" - tip/tilt/xlate perp to optical bench w/shims BS Cube Assyoptical benchN/ARotation within fastener hole clearance L1 Assyoptical benchN/A'X' focus slot ±.125" - 'Y' rail ±.005" L2 Assyoptical benchN/A'X' focus slot ±.0625" - 'Y' rail ±.005" F1 Assyoptical bench.010" - tip/tilt (centering not critical) N/A L3 Assyoptical benchN/A'X' focus slot ±.0625" - 'Y' rail ±.005" L4 Assyoptical benchN/A'X' focus slot ±.0625" - 'Y' rail ±.005" M4 Assy'L' Bracket to optical bench.020" - tip/tilt/xlate perp to optical bench w/shims Dichroic Wedge'L' Bracket to optical bench.020" - tip/tilt/xlate perp to optical bench w/shims L5 Assyoptical benchN/A'X' focus slot ±.0625" - 'Y' rail ±.005" Field Stop Assyoptical benchN/A  For all we don't adjust with shims, tolerance should control to 0.1°  'Y' adjust required on lens really depends on centering tolerance in mount - consider.005" nominally

27 27 Mechanical Systems Peer Review Assembly Process/Plan  All components and GSE shall be handled and assembled with strict adherence to the MIGHTI Contamination Control Plan  Optical Bench and Aft Optics Housing heaters installed prior to optics integration  Optical Bench mounted with GSE perpendicular to an optical table Baffle installed to set external optical alignment features Baffle removed for access to Entrance Pupil (A1 Aperture) Optics and Camera (under vacuum) installed and aligned Optical Cube installed and alignment measurements taken  Optical Bench/Optics manually moved from optical table to a FLOTRON® rotatable holding fixture with custom interface GSE for ease of access to instrument in all orientations Install and adjust LYOT Stop Shutter (A2) Install internal bench thermal components and route wiring Install optics enclosure, Camera to enclosure light tight interface and Optics enclosure cover Reinstall Baffle Assembly (Baffles and Door installed and aligned on Baffle prior to final integration) Install thermal control tapes and/or MLI  Instrument Flexures install with alignment GSE to test plate  Instrument integrated onto Flexures FLOTRON®

28 28 Mechanical Systems Peer Review Mass Properties - Summary Part Description Mass CBE (kg) Contingency (%) CBE + Contingency (kg) Structures (Primary, Secondary)14.9719%17.74 Baffle Assembly4.9920%5.98 Optics and Optomechanics3.3215%3.82 Interferometer Assembly1.5915%1.83 Camera Head3.0420%3.65 Instrument Thermal Control Subsystem4.4620%5.35 Mechanisms & Drivers1.7715%2.04 Ancillary0.6420%0.76 Calibration Lamp Assembly1.7615%2.02 Camera Electronics Assembly4.3320%5.20 Total40.8818.4%48.40  All mass numbers are for the 2 MIGHTI instruments together except for the Calibration Lamp and the Camera Electronics which only have one component each supporting the 2 MIGHTIs  Overall design is not yet fully optimized for mass  Contingency reflects maturity of design and components

29 29 Mechanical Systems Peer Review Mass Properties – CBE Detail

30 Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) Instrument Preliminary Peer Review Structure Jon Shaw 3/19/14

31 31 Mechanical Systems Peer Review  Key Structural Requirements  Environments & Factors of Safety  MIGHTI FEM  MIGHTI Analysis Results Normal Modes MAC Stress Assessment Thermal induced stress and distortion  Aperture Door  Shutter Assemblies  Calibration Lamp Flexure  Electronics Box Flexure  Summary Structural Analysis Outline

32 32 Mechanical Systems Peer Review  Stiffness Fixed-Base fundamental frequency of the MIGHTI Instrument shall be at least 100 Hz.  Structural Integrity Demonstrate positive margins of safety under applicable loads environments and Factors of Safety  Thermally-Induced Interface Loads Shear load at PIP interface at survival thermal environment shall be less than 75# for MIGHTI (38# for smaller components) Shear load at PIP interface at operational thermal environment shall be less than 60# for MIGHTI (30# for smaller components) Key Structural Requirements

33 33 Mechanical Systems Peer Review  MAC * 1.0 used as Design Limit Load  Survival Temperature: -55C Cold Soak  Operational Temperature: 20C Bench/25C IF Oven/-55C Elsewhere  Factors of Safety: Environments & Factors of Safety 25 g’s Type of Hardware Factors of Safety YieldUltimate Tested Flight Structure – metallic1.31.5

34 34 Mechanical Systems Peer Review FEM Description/Overview/Details  NASTRAN FEM is approx 15,000 elements. Primarily composed of plate elements  Secondary structure (camera, mirrors, optics, etc) modeled with CONM2 & RBE2  Constrained at PIP fastener locations  FEM passes 1g and grounding checks  FEM mass matches predicted mass + MGA (~21kg)

35 35 Mechanical Systems Peer Review Normal Modes  First flexible mode @ 105Hz  Second flexible mode @ 111Hz Modal Effective Mass (Percent of Total) Mode #FREQTxTyTzRxRyRz 1105.3260.90%1.30%2.90% 4.61%6.95% 18.46% 2110.742.50%0.50%27.00%67.97%32.49% 0.20% 3136.290.00%1.00%0.50% 0.62%8.52%0.32% 4165.526.70%0.00%36.80% 1.19%3.05%0.35% 5176.180.10%1.00%0.00% 7.53%0.77%2.31% 6186.350.00%1.90%0.80% 0.00%0.76%8.10% 7188.5121.30%1.10%11.70% 0.24%6.57%1.75% 8222.381.80%0.60%4.30% 0.32% 14.24% 0.08% 9273.340.00%25.40%0.30% 0.31%0.01% 18.61% 10296.590.60%3.50%0.60% 0.10%0.40%3.47% 11315.551.10%2.60%6.20% 2.03% 11.28% 2.40% 12328.080.00%1.60%2.40% 1.85%2.45%0.17% 13343.591.00%16.00%0.20% 3.63%0.90%7.65% 14365.940.10%0.00%0.10% 0.03%0.00%0.08% 15380.080.60%4.40%0.00% 0.11%0.07%5.22% 16384.530.00%1.80%0.30% 0.01%0.05%1.37% 17417.280.10%0.90%0.10% 1.42%1.05% 18421.670.00%0.20%0.50% 0.00%2.05%0.23% 19429.160.20%3.20%0.10% 0.08%0.84%0.71% 20435.670.00%0.10% 0.01%0.17%0.22%

36 36 Mechanical Systems Peer Review MAC Stress Assessment – Aluminum Components X Axis MAC – 8.2 ksi peak stress Z Axis MAC – 5.6 ksi peak stress Y Axis MAC – 3.7 ksi peak stress Aluminum Margins of Safety Load Case Margins, using Corner Stress & Test FS MSyMSu MAC X 2.472.41 MAC Y 6.696.57 MAC Z 4.084.00

37 37 Mechanical Systems Peer Review MAC Stress Assessment – Titanium Components X Axis MAC – 23 ksi Z Axis MAC – 6.9 ksi Y Axis MAC – 17 ksi Titanium Margins of Safety Load Case Margins, using Corner Stress & Test FS MSyMSu MAC X 0.240.22 MAC Y 0.670.65 MAC Z 3.123.06

38 38 Mechanical Systems Peer Review Thermal Environments MetricMax Value Peak Stress***22ksi MSy0.29 MSu0.27 RSS I/F Shear21# Survival (w/stress contour) Operational (w/displacement contour) MetricMax Value RSS I/F Shear1.6#

39 39 Mechanical Systems Peer Review Door Bracket Door Pin Puller  FEM captures primary structural components and load paths Secondary components captured as mass elements or NSM Model constrained at Door Bracket and Pin Puller Bracket Instrument Interfaces  Load Paths Pin Puller carries any load which opens door Alignment cone carries any load which closes door and X direction lateral load Bearings carry all the vertical load  Model built to CBE mass 1.2 factor used on Param,WTMASS card to scale model up to NTE mass  Passes all standard model checks 1g constraint forces sum to model mass 6 rigid body modes/No grounding Aperture Door Mechanism

40 40 Mechanical Systems Peer Review Aperture Door Mechanism – Normal Modes 1 st Mode – 110.81 Hz2nd Mode – 126.02 Hz3 rd Mode – 239.28 Hz

41 41 Mechanical Systems Peer Review  Analysis Parameters MAC load for components < 1kg is 58 g Test FOS applied to recovered stresses to calculate MOS  1.3 Yield, 1.5 Ultimate 1g loads applied in model X, Y, and Z directions  Stress enveloped across all load cases  Results scaled up to 58g  Aluminum 6061-T6 Components Includes Door, Door Bracket, Film Bracket, Latch, Pin Puller Bracket, and Alignment Cone Max stress is 17 ksi  Occurs in door at thickness transition under 58g Z-direction loading MOSy =.58, MOSu =.65  Cres Components Torsion Spring Mandrel Max Stress is 43 ksi MOS = high Aperture Door Mechanism – MAC Stress Assessment Max Stress =.292 ksi x 58g = 17 ksi

42 42 Mechanical Systems Peer Review  Pin Puller Total force = 1.42 lb pre-load + 7.8 lb due to 58g launch load = 9.22 lb Rated load under actuation is 10 lb (includes FOS) MOS =.085  Bearings Rated static load capacity 31 lb (includes FOS) Max radial force due to 58 g launch load is 19.91 lb MOS =.56  Torsion Spring Total torque applied is 9.8 in-lb Stress in spring due to torque is 215.7 ksi Music Wire allowable is 220 ksi (includes FOS) MOS =.019  Compression Spring (Energy Absorber) Rated for.270 lb compression force (includes FOS) Total compression = 0.10”  Results in.13 lb force in spring MOS = 1.0 Aperture Door Mechanism – MAC Stress Assessment

43 43 Mechanical Systems Peer Review A1 and A2 Shutter Mechanisms  FEM captures primary structural components and load paths Secondary components captured as mass elements or NSM Model Constraints A1 constrained at Fold Mirror Housing I/F A2 constrained at bracket base  Model built to CBE mass 1.2 factor used on Param,WTMASS card to scale model up to NTE mass  Passes all standard model checks 1g constraint forces sum to model mass 6 rigid body modes/No grounding A2 Shutter Mechanism (F1770) A1 Shutter Mechanism (F1775) Shown W/O CoverShown With Cover A1Shutter MassA2 Shutter Mass

44 44 Mechanical Systems Peer Review A1 and A2 Shutter Mechanisms – Normal Modes A1 Shutter Mechanism (F1775)A2 Shutter Mechanism (F1770) 1 st Mode – 154.55 Hz2 nd Mode – 284.96 Hz1 st Mode – 315.39 Hz2 nd Mode – 396.62 Hz

45 45 Mechanical Systems Peer Review  Analysis Parameters MAC load for components < 1kg is 58 g Test FOS applied to recovered stresses to calculate MOS  1.3 Yield, 1.5 Ultimate 1g loads applied in model X, Y, and Z directions  Stress enveloped across all load cases, results scaled up to 58g A1 and A2 Shutter Mechanism – MAC Stress Assessment Max Stress =.192 ksi x 58g = 11.14 ksi MOSy = 1.4, MOSu = 1.5 A1 Shutter Mechanism (F1775) A2 Shutter Mechanism (F1770) Max Stress =.136 ksi x 58g = 7.86 ksi MOSy = 2.4, MOSu = 2.6

46 46 Mechanical Systems Peer Review Calibration Lamp Flexure The calibration lamp base provides thermal/electrical isolation as well as integral flexures to limit the shear forces at the PIP interface Base is a thin-walled (.060”) titanium design,.5” tall, with.030” thick flexures at all interface fastener locations. Weight is.21lbs. Driving Requirements: 1. Frequency of assembly > 100hz (Predict 178hz. See above) 2. Shear force into PIP at survival temp < 60# 3. Positive stress margin under design limit loads Flexures allow radial expansion/contraction

47 47 Mechanical Systems Peer Review Calibration Lamp I/F Loads and Stress Margins Flexure Margins of Safety Load Case From Corner Stress with Test FS MSyMSu MAC X 0.400.31 MAC Y 0.280.20 MAC Z 0.650.55 TT 0.250.18 Flexure to PIP Fastener Loads Load Case AxialRSS ShearMomentTorque (lbf) (in-lbf) TT 0.058.214.50.64

48 48 Mechanical Systems Peer Review  We have a FEM of this electronics box, so we have a realistic representation of the box dynamics.  We intend to utilize variation of Calibration Lamp flexure to support Camera Electronics Box Camera Electronic Box

49 49 Mechanical Systems Peer Review  Structures meet frequency and I/F shear force requirements and show positive stress margin under design limit loads.  Accommodations have been made to allow for differential thermal expansion, and to limit the thermally induced distortion of the optical bench  Working to establish operational optical requirements (both total line-of-sight error and allowable distortion at each optical component) and designing to meet those requirements under thermal environment. Structural Analysis – Summary

50 50 Mechanical Systems Peer Review  Refine Interferometer mount design and structural analysis  Resolve design of heat pipe to camera interface (heat pipe support, radiator support, camera interface)  Analyze line of sight error/thermal distortion  Finalize Vane attachment to baffle assembly design  SMR Interfaces  Calibration Lamp flexure design  Camera Electronics Box flexure design  Refine calibration optics design  Fiber optic routing and support  Thermal component layout  Purge/vent system  Ground wires  Wire harness routing  Design optimization for mass reduction  GSE Future Design Activities


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