Outline

1. Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) InstrumentPreliminary Peer ReviewMechanical SystemsE. Stump3/19/14

2. Outline • MIGHTI Overview • Mechanical Driving Requirements • Mechanical Design Overview • Interfaces and Interface Control Documentation • Optics Mechanical Alignments • CBE Mass • Structure Analysis Summary • Future Design Activities

3. Overview (1 of 3) ICON • MIGHTI is a key instrument on the NASA Class C IonosphericCONnection 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) 630.0nm 557.7nm 762.0nm MIGHTI Behind (B) MIGHTI Ahead (A)

4. MIGHTI Overview (2 of 3) • 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

5. Mechanical System Driving Requirements (L4)

6. Mechanical System Driving Requirements (L4)

7. Mechanical System Driving Requirements (L4)

8. Mechanical System Driving Requirements

9. Mechanical Design – Layout – MIGHTIs on PIP MIGHTI B • 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 Camera Electronics Calibration Lamp MIGHTI A Y X SC

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

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

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

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

14. Mechanical Design – Dimensional Layout - Instrument

15. Mechanical Design – Dimensional Layout – Cal Lamp & Ebox

16. Mechanical Design – Dimensional Layout - PIP

17. Mechanical Design - Layout Field Of View 90° Keep Out Zone

18. Mechanical Design – Interferometer Mount/Oven • 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) Top Plate Interferometer Fixed Top Interferometer Contacts Spring Loaded Bottom Interferometer Contacts Base Plate Thermal Isolators

19. Mechanical Design - Interfaces

20. Mechanical Design – Interface to PIP • 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.

21. Mechanical Design – Interface to PIP • 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

22. Mechanical Design – Heat Pipe to Camera Heat Pipe Clamp Assy Thermally isolated from bench • 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 Beryllium Clamp/Saddle Thermal contact area Heat Pipe to TEC Hot Side

23. Mechanical Design – Calibration Optics (external) OAP Cover / Mount Plate • 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 Fold Mirror Fiberoptic Bulkhead Beam Splitter Assembly Fold Optics Contingency Location

24. Detailed Design - Structures Radiator Mount Baffle/Radiator Support • 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 Radiator Flexure Radiator Mounts Radiator Baffle Enclosure & Baffles Entrance Pupil/ Shutter Housing Aft Optics Enclosure Baffle/Radiator Supports Optical Bench Optical Enclosure & Cover Instrument Flexures

25. Optics Mechanical Alignment • 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 Instrument Coordinates GSE Focus Rail (typ) Optical Table GSE Bench Supports

26. Optical Alignment Budget • 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. 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. Mass Properties - Summary • 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. Mass Properties – CBE Detail

30. Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) InstrumentPreliminary Peer ReviewStructureJon Shaw3/19/14

31. Structural Analysis Outline • 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

32. Key Structural Requirements • 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)

33. Environments & Factors of Safety • 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: 25 g’s

34. 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. Normal Modes • First flexible mode @ 105Hz • Second flexible mode @ 111Hz

36. MAC Stress Assessment – Aluminum Components X Axis MAC – 8.2 ksi peak stress Y Axis MAC – 3.7 ksi peak stress Z Axis MAC – 5.6 ksi peak stress

37. MAC Stress Assessment – Titanium Components Z Axis MAC – 6.9 ksi X Axis MAC – 23 ksi Y Axis MAC – 17 ksi

38. Thermal Environments Survival (w/stress contour) Operational (w/displacement contour)

39. Aperture Door Mechanism Door Bracket • 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 Door Pin Puller

40. Aperture Door Mechanism – Normal Modes 1st Mode – 110.81 Hz 2nd Mode – 126.02 Hz 3rd Mode – 239.28 Hz

41. Aperture Door Mechanism – MAC Stress Assessment • 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 Max Stress = .292 ksi x 58g = 17 ksi

42. Aperture Door Mechanism – MAC Stress Assessment • 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

43. 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) Shown With Cover Shown W/O Cover A1Shutter Mass A2 Shutter Mass A1 Shutter Mechanism (F1775)

44. A1 and A2 Shutter Mechanisms – Normal Modes A1 Shutter Mechanism (F1775) A2 Shutter Mechanism (F1770) 1st Mode – 154.55 Hz 2nd Mode – 284.96 Hz 1st Mode – 315.39 Hz 2nd Mode – 396.62 Hz

45. A1 and A2 Shutter Mechanism – MAC Stress Assessment • 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 A2 Shutter Mechanism (F1770) A1 Shutter Mechanism (F1775) Max Stress = .136 ksi x 58g = 7.86 ksi MOSy = 2.4, MOSu = 2.6 Max Stress = .192 ksi x 58g = 11.14 ksi MOSy = 1.4, MOSu = 1.5

46. Calibration Lamp Flexure Flexures allow radial expansion/contraction 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

47. Calibration Lamp I/F Loads and Stress Margins

48. Camera Electronic Box • 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

49. Structural Analysis – Summary • 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.

50. Future Design Activities • 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