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Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) Instrument Preliminary Peer Review Thermal W. Tolson.

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Presentation on theme: "Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) Instrument Preliminary Peer Review Thermal W. Tolson."— Presentation transcript:

1 Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) Instrument Preliminary Peer Review Thermal W. Tolson

2 2 Thermal Peer Review  MIGHTI Overview  Thermal Requirements Level 4 – Direct Level 5 Derived Temperature Limits  Design Approach – Overall  Thermal Design Heat Pipe / Radiator Assembly TEC to Heat Pipe Interface Camera Housing Optical Bench Interferometer Aft Optics Baffle Camera Electronics Calibration Lamp Mechanisms Outline  Thermal Control Hardware  Thermal Model Geometric Configuration Giver-Receiver Information Exchange Assumptions  Thermal Analysis Results Summary TEC Dissipation Transient Results  Trade Studies  Testing  Plan Forward

3 3 Thermal 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 & 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) MIGHTI Overview (1 of 3) MIGHTI Ahead (A) MIGHTI Behind (B) ICON 630.0nm 557.7nm 762.0nm

4 4 Thermal Peer Review  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 Thermal Peer Review MIGHTI Overview (3 of 3) – Instrument Layout Optical Bench Transfer 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 Radiator One Shot Door

6 6 Thermal Peer Review Thermal Requirements: Level 4 – Direct (1 of 3) 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-4-4The MIGHTI instrument shall be designed for an orbit with a targeted BOL inclination of 27 degrees. M-4-5The MIGHTI instrument shall be designed for an End of Life (EOL) orbit with a minimum altitude of 450 km. M-4-6The MIGHTI instrument shall be designed to accommodate orbit injection errors: +/ inclination error, +/-10 km insertion apse error, +/- 80 km non-insertion apse error (all errors are 3 sigma) without impact to top level requirements. M-4-7The MIGHTI post-launch checkout shall take less than 20 days, assuming a nominal ground contact schedule (5 passes/day). M-4-28The monochromatic interferogram fringe contrast, including the contrast reduction resulting from the detector sampling (pixel width) shall be greater than or equal to 76% % across the optical path difference interval, decreasing for increasing optical path.

7 7 Thermal Peer Review Thermal Requirements: Level 4 – Direct (2 of 3) NumberRequirement 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. M-4-132The MIGHTI instrument shall withstand the Sun within the FOV not to exceed TBD minutes without serious degradation. (based on transit of the sun across the field of view at an angular rate determined by the orbital altitude) M-4-133The MIGHTI instrument shall be designed to maintain Allowable Flight Temperatures (AFTs) in survival mode for (TBD) minutes when the payload is pointed anywhere in the celestial sphere at any time during the mission. 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.

8 8 Thermal Peer Review Thermal Requirements: Level 4 – Direct (3 of 3) NumberRequirement 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 25°C  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 20°C  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. [TBD: sensors on cal lamps and camera electronics]

9 9 Thermal Peer Review Thermal Requirements: Level 5 – Derived (1 of 2) NumberRequirement M-5-1Thermal analysis shall include winter solstice, summer solstice, and equinox seasons. M-5-2Thermal control surface degradation is to take into account 25 months of orbital exposure M-5-3All components shall be kept within their operational limits when payload power is applied. M-5-4The MIGHTI Instrument shall preclude the use of liquid cryogens for cooling. M-5-5The MIGHTI Instrument shall preclude the use of expendable gases for cooling. M-5-6Thermal control during survival mode shall rely upon non-commandable means (Mechanical thermostats) M-5-7All components shall be kept within their survival temperature limits. M-5-8The interferometer housing shall be controlled to 25°C ± 0.1°C M-5-9The optical bench shall be controlled to 20°C ± 2°C M-5-11All components shall be kept within their survival temperature limits at all times.

10 10 Thermal Peer Review Thermal Requirements: Level 5 – Derived (2 of 2) NumberRequirement M-5-12MIGHTI shall add SC powered heaters during instrument I&T. M-5-13MIGHTI shall incorporate means of connecting SC powered heaters to harness during payload I&T. M-5-14SC powered heaters shall be sized to keep MIGHTI above survival temperature minimum limits. M-5-15Interferometer oven shall have sufficient temperature monitoring points to allow for precision control. M-5-16Control system shall have sufficient resolution, amplification, and noise filtering to allow for precision control. M-5-17Power Supply and Return lines for operating heaters shall be twisted pair. M-5-18Heaters shall be designed to minimize or negate the magnetic moments when power is supplied.

11 11 Thermal Peer Review Thermal Requirements: Temperature Limits

12 12 Thermal Peer Review  Optical Bench Assembly Thermally isolate from PIP & Baffle Software (ICP) controlled active heater control to maintain temperature stability Radiators sized to maintain active heater control margin (>30%) for all on orbit hot-cold operational conditions (MLI on non-radiating surfaces Radiator, heater, and temperature sensor locations optimized to minimize spatial temperature gradients NOTE: Design pending completion of ongoing analysis  Camera CCD Thermally isolated TEC for CCD active thermal control; camera internal design by SDL Fin radiator heat pipe assembly to transport and reject TEC dissipation and associated parasitic loads  Electronics Passive radiator design; radiators sized to protect hot case limits (MLI on non-radiating surfaces) Thermostat controlled operational heaters to protect cold limits as required  Thermostat controlled heaters to protect survival temperature limits NOTE: survival / safe-mode analysis pending  Structure MLI to damp orbital (day-night) temperature excursions Design Approach– Overall

13 13 Thermal Peer Review  Fin Radiator (2) 1/16” thick 6061 Al face-sheets 2.4 PCF Al core A = 2 x 144 in 2 Z93 white paint; both sides Thermal isolation at supports (4 places) Titanium flexure supports (2)  Heat Pipe Dual bore 0.75” x 0.375” Al extrusion Working fluid ammonia h e / h c = 1.5 / 2.5 W/in/ o C In plane Exposed length MLI Embedded in radiator core Bonded to radiator face-sheets (2) 3/8” contact (2 sides) along radiator full length Thermal Design – Heat Pipe / Radiator Assembly

14 14 Thermal Peer Review  Heat pipe clamp assembly Thermally isolated from bench Thermal design pending  TEC hot side interface SDL design need mC p = 119 J/ o C See power dissipation table in thermal model assumptions section  Heat pipe evaporator flange A contact = 1.75” x 2.75” thermal gap filler h = 2.5 W/in 2 / o C  Heat pipe clamp / saddle Mass to damp orbital transient temperature swings Beryllium m = kg (0.016 lb) Material optimized to minimize absolute mass while maximizing thermal mass (mC p ) Thermal Design – TEC to Heat Pipe Interface

15 15 Thermal Peer Review  Camera Housing Thermally isolated from bench <0.05 W/ o C; verification/margin pending bench detailed analysis 560 mW internal electronics dissipation Housing radiator area Z93 white paint or Ag Teflon tape Partial radiator area on 2 sides shown Required radiator area pending analysis Non-radiator area and cabling MLI MLI light seal at camera / bench interface Thermostat controlled operational / survival heaters as required Thermal Design – Camera Housing Partial radiator area 2 sides TEC hot side interface

16 16 Thermal Peer Review  Optical Bench Thermally isolated from PIP Machined 6061 Aluminum Internal dissipation negligible Active heater control Up to 3 operational circuits Operational heaters software controlled Operational heaters maintain 20 o C +/- 2 o C; transient & spatial Heaters designed to maintain continuous active control (hot-cold environment range)  Design margin 30% Survival heaters thermostat controlled Heater size/location definitions pending ongoing analysis Z93 white paint structure radiators Radiator design & analysis ongoing Non-radiating surfaces MLI Interior high emissivity Thermal Design – Optical Bench  Cover (not shown) Passive Diffuse high emissivity interior MLI on outside surfaces Interferometer Oven Camera Bench

17 17 Thermal Peer Review  Interferometer Thermally isolated from support structure No internal dissipation  Cover Thermally coupled to base plate Active heater control; 3 temperature sensors  2 high resolution; 1 low resolution 1 heater circuit (multiple heaters) Operational heaters maintain 25 o C +/- 0.1 o C; transient & spatial Operational heaters designed to maintain continuous active control  Design margin 30% Heater size/location definitions pending ongoing analysis Outside surface MLI Inside surface diffuse / high e  Base Plate Thermally isolated from bench Bottom side facing bench Al tape (low e) Top side facing interferometer diffuse / high e Thermal Design – Interferometer Interferometer Top Plate Base Plate Thermal Isolators Fixed Top Interferometer Contacts Spring Loaded Bottom Interferometer Contacts Cover

18 18 Thermal Peer Review  Aft Optics & Shutter Housing Thermally coupled to bench Thermally isolated from baffle Internal dissipation negligible Single temperature sensor Active heater control 1 circuit (design pending analysis) Operational heaters software controlled Operational heaters maintain 20 o C +/- 2 o C; transient & spatial Heaters designed to maintain continuous active control (hot-cold environment range)  Design margin 30% Survival heaters thermostat controlled Survival heater circuit combined with bench Heater size/location definitions pending ongoing analysis Z93 white paint structure radiators Radiator design & analysis ongoing Non-radiating surfaces MLI Interior high emissivity Thermal Design – Aft Optics Aft Optics Enclosure Entrance Pupil & Shutter Housing Stepper Motor

19 19 Thermal Peer Review  Baffle Structure Thermally isolated from Aft Optics Thermally isolated from supports Passive thermal control High emissivity interior MLI on outside surfaces Thermal Design – Baffle

20 20 Thermal Peer Review  CEB radiator 12 W internal electronics dissipation Assumed dissipation at radiator Z93 white paint on front and fin back  CEB housing Thermally isolated from PIP Model assumes no conduction to PIP (conservative) PIP temperature range -20 o C to +40 o C per SSL/Berkley Interface conductance requirement TBD by SDL & SSL/Berkley Housing and cabling MLI Thermostat controlled survival heaters as required Thermal Design – Camera Electronics

21 21 Thermal Peer Review  Lamp Housing 8 W internal electronics dissipation Assumed dissipation uniform over housing Ag Teflon tape on housing Thermally isolated from PIP <0.05 W/ o C cabling MLI Thermostat controlled survival heaters as required Thermal Design – Calibration Lamp

22 22 Thermal Peer Review  Aperture Door Thermal design & analysis pending Deployment heater as required  Stepper Motors Thermal analysis pending Aft optics motor MLI Bench Motor radiates to OB cavity Conduction at mounting interface Low power duty cycle Design Approach – Mechanisms Baffle Door Door Pin Puller Optical Bench Aft Optics Stepper Motors Baffle Door

23 23 Thermal Peer Review  Thermistors Manufacturer: Measurement Specialties Part # 311P18-06A101 5K Ohm 25 o C  RTD’s Manufacturer: Goodrich Corp. Part # 0118MF-2000-A 2K Ohm resistance  Heaters Manufacturer: Tayco Type: TPC-6002 Flexible Kapton  Thermostats Manufacturer: Honeywell Type: 701 series bi-metallic/mechanical  MLI 1 outer Layer: 2.75 mil Germanium Black Kapton (GBK) 13 middle layers: 0.25 mil Aluminized Mylar (VDA2) 14 separators: B4A Dacron mesh 1 inner layer: 2 mil Kapton (VDA1) Material Vendors: Sheldahl; Dunmore Thermal Control Hardware

24 24 Thermal Peer Review  Temperature Sensor Specifications Thermal Control Hardware LocationTypeCountMonitored Cal LampTHM2ICP TEC cold side (A&B)RTD2ICP TEC hot side (A&B)THM2ICP Optical Bench (A&B)THM6ICP Interferometer (A&B) (2 coarse,1 fine per IF) THM6ICP Aperture motors (A&B) (may not need) THM4ICP Aft Optics (A&B) (likely will need to add) THM2ICP Optical Bench (A&B)THM2SC TEC cold side (A&B) (may not need) THM2SC Camera ElectronicsTHM1SC Door Actuator (A&B) (likely will need to add) THM2SC Camera Housing (A&B) (likely will need to add) THM2SC  Heater Specifications Circuit ZoneBusControlNotes Optical Bench (A&B)OPICP1,5 Interferometer (A&B)OPICP1,5 Aft Optics (A&B)OPICP1,5 Camera Housing (A&B)OPTSTAT2,5 Camera ElectronicsOPTSTAT3,5 Calibration LampOPTSTAT3,5 Optical Bench (A&B)SVLTSTAT4,6 Camera Housing (A&B)SVLTSTAT4,6 Camera ElectronicsSVLTSTAT4,6 Calibration LampSVLTSTAT4,6 1)Software controlled 2)Pending analysis 3)Current analysis indicates likely not needed 4)4 Pending survival / safe mode analysis 5)Operational bus 28-34V 6)Survival / Safe Mode bus 24-34V

25 25 Thermal Peer Review  Instrument Suite & Payload Interface Platform (PIP) Thermal Model: Geometric Configuration MIGHTI-B MIGHTI-A Camera Electronics Box (CEB) Calibration Lamp Payload Interface Platform (PIP)

26 26 Thermal Peer Review  MIGHTI Instrument Assembly Thermal Model: Geometric Configuration Optical Bench OB Cover Aft Optics Camera TEC Radiator Conductor-Heat Pipe to Radiator Baffle Radiator Supports (1 of 2)

27 27 Thermal Peer Review  Camera Electronics Box (CEB) & Calibration Lamp Thermal Model: Geometric Configuration CEB Radiator CEB Housing Calibration Lamp Housing

28 28 Thermal Peer Review  Thermal Model Format Autocad 2014; Thermal Desktop / SindaFluint -Version 5.6  ATK to SSL Reduced MIGHTI instrument Assembly  MIGHTI-A; MIGHTI-B; Camera Electronics Box (CEB); Calibration Lamp  Include geometry; optical properties; thermal masses; conduction network; transient dissipations  SSL to ATK Reduced PIP & Instrument Suite (geometry & optical properties only)  ATK to SDL Preliminary CEB radiator size CEB environmental and IR backload heat loads (transient)  SDL to ATK CEB mechanical configuration & internal power dissipation TEC hot side temperature vs. power profile Thermal Model: Giver-Receiver Information Exchange

29 29 Thermal Peer Review  Orbits Beta = 50 o Beta = 0 o Beta = -50 o Thermal Model: Assumptions  Altitude Circular 576 km (nominal)  Evaluation of altitude range 450 km to 665 km pending  Vehicle Attitude Operational: +Z Nadir / +X velocity vector  Beta angle versus Time of Year

30 30 Thermal Peer Review  Optical Properties  Environments Thermal Model: Assumptions

31 31 Thermal Peer Review  Component Power Dissipations  TEC Power Dissipation Thermal Model: Assumptions

32 32 Thermal Peer Review  Component Masses (as modeled) Cal Lamp – 1.5 kg Baffle – 1.84 kg Camera Electronics – 2.65 kg TEC Hot Side – kg  Material Properties Thermal Model: Assumptions

33 33 Thermal Peer Review  Mechanical  Multi-Layer Insulation (MLI) Effective Emittance Larger blankets: e* = 0.01 to 0.03 Smaller blankets: e* = 0.03 to 0.10 Thermal Model: Assumptions

34 34 Thermal Peer Review  Operational Hot Case Thermal Analysis: Results Summary

35 35 Thermal Peer Review  Operational Cold Case Thermal Analysis: Results Summary

36 36 Thermal Peer Review  TEC Hot Case Orbit Average Dissipation TEC hot side parasitic heat load not included Thermal Analysis: TEC Dissipation Beta AngleTEC A Orb Avg Dissipation (w) TEC B Orb Avg Dissipation (w)

37 37 Thermal Peer Review Thermal Model: Analysis Transient Results – TEC Hot Side  Hot – Beta -50° - MIGHTI A/B  Cold – Beta 0° - MIGHTI A Cold – Beta +50° - MIGHTI B

38 38 Thermal Peer Review Thermal Model: Analysis Transient Results – Radiators  Hot – Beta -50° - MIGHTI-A Hot – Beta -50° - MIGHTI-B  Cold – Beta 0° - MIGHTI-A Cold – Beta +50° - MIGHTI-B

39 39 Thermal Peer Review Thermal Model: Analysis Transient Results - Baffles  Hot – Beta +50° - MIGHTI-A Hot – Beta +50° - MIGHTI-B  Cold – Beta -50° - MIGHTI-A Cold – Beta -50° - MIGHTI-B

40 40 Thermal Peer Review Thermal Model: Analysis Transient Results – Electronics  Hot – Beta -50° - Camera Electronics & Calibration Lamp  Cold – Beta +50° - Camera Electronics & Calibration Lamp

41 41 Thermal Peer Review  Thermal Strap Trade Studies: Thermal Strap vs. Heat Pipe (1 of 2) Concerns Imposing system level test constraints to keep heat pipes in reflux orientation Reflux test configuration will require starter heaters that may affect thermal balance Operation in 0-g is not possible under acceleration Advantages Light weight solution Spreads heat along entire radiator length Redundant heat pipes will slightly reduce operating temperatures during life Flight heritage Negligible end to end DT Advantages Gravity independent testing Reduced complexity and handling No freeze protection necessary Concerns Mass (Only viable option is graphite) # of Layers required for flexible strap portion likely not viable. K-Tech recommends max 10 layer strap. Our application requires a 1.75” x 2” solid >11 lb. to match pipe performance Length increases as routing details are introduced Significantly lower conduction through strap/bar thickness (relative to axial) introduces uncertainty in conductance to radiator Flex Strap does not meet requirements for extreme beta angle seasonal conditions. Heavy solid bar would be required.  Heat Pipe

42 42 Thermal Peer Review  Summary of Results  Conclusion Thermal strap not a viable option  3 lb m solid K-Core section does not meet requirements for high beta angle conditions  Likely mass required >6 lb m to meet requirements (11 lb m for heat pipe equivalent performance) Heat pipes meet requirements for worst case on orbit conditions  2-3 lb m within practical application  Orbit average TEC dissipation reduced relative to strap  Heat pipe cost comparable to strap: ROM approximately $30-50K  Testing considerations/restrictions can be accommodated Trade Studies: Thermal Strap vs. Heat Pipe (2 of 2)

43 43 Thermal Peer Review  Standards per GEVS GSFC-STD-7000A Thermal vacuum qualification standards to ensure that the payload operates satisfactorily in a simulated space environment at more severe conditions than expected during the mission.  Component / Unit Level Typically done by vendor Applicable to components with power dissipation: camera, CEB, calibration lamp, motors, actuators 1 survival cycle Minimum of 8 thermal vacuum operational temperature cycles Minimum of 4 hours at each extreme of each temperature cycle  Subsystem / Instrument Level 1 survival cycle Minimum of 4 operational thermal vacuum temperature cycles Minimum of 12 hours at each extreme of each temperature cycle Thermal balance: survival, hot operational, cold operational  Payload/Spacecraft Level 1 survival cycle 4 thermal vacuum operational temperature cycles (2 with project approval; dwell times doubled) Minimum 24 hours at each extreme of each temperature cycle Thermal balance as practical Testing (1 of 2)

44 44 Thermal Peer Review  Functional testing At each operational temperature plateau Turn on test following recovery from survival plateau (usually combined with functional test)  Test Margins See notes associated with temperature limits table  Considerations/limitations Likely auxiliary GSE required for radiator temperature control; instrument & payload/SC level  GN 2 / heater controlled panels Heat pipes must be oriented to perform in “reflux” mode  Evaporator (TEC) must be lower than condenser (radiator) relative to gravity  No limitation for +Z axis vertical  For +Z axis horizontal vehicle must be clocked about Z axis to maintain reflux; approximately 90 o rotation window Testing (2 of 2)

45 45 Thermal Peer Review  Optical Bench Assembly Includes bench, cover, aft optics, interferometer (no optical components except IF) Complete high fidelity thermal models Incorporate interface conductance effects per previous chart Optimize radiator sizes, locations (NA for interferometer) Define operational heater layout  Heat Pipe Radiator Assembly Complete feasibility evaluation incorporating a short thermal strap at TEC/pipe interface  Effort to gain additional mechanical compliance to mitigate camera alignment/distortion issue  Camera Complete housing radiator design Determine if housing needs to be thermally coupled to optical bench  Camera Electronics Good shape for PDR  Calibration Lamp Refine housing radiator size/location  Other Clarify all temperature limits Survival / safe-mode analysis to determine heater requirements Update PIP geometry to include star tracker radiator blockage effects (likely negligible) Plan Forward to PDR


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