1 / 56

THEMIS Electric Field Instrument (EFI) Mission CDR The THEMIS EFI Team

THEMIS Electric Field Instrument (EFI) Mission CDR The THEMIS EFI Team. Outline. Personnel and Organization Summary of EFI Status at MCDR Requirements, Specifications, and Design Compliance Requirements Top-Level Design Error Budgets Status of Subsystem Design, Fabrication, and Testing

heath
Download Presentation

THEMIS Electric Field Instrument (EFI) Mission CDR The THEMIS EFI Team

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. THEMIS Electric Field Instrument (EFI) • Mission CDR • The THEMIS EFI Team

  2. Outline • Personnel and Organization • Summary of EFI Status at MCDR • Requirements, Specifications, and Design Compliance • Requirements • Top-Level Design • Error Budgets • Status of Subsystem Design, Fabrication, and Testing • Fabrication, Integration, and Test • Schedule: Henry Ford Help Us… • Operations Planning • Deploy and Commisioning • Etc.

  3. Personnel and Organization • Organizational Chart (all UCB unless noted): • Prof. F. Mozer (EFI Co-I). • Drs. J. Bonnell, G. Delory, A. Hull (Project Scientists) • P. Turin (Lead ME), Dr. D. Pankow (Advising ME) • B. Donakowski (EFI Lead ME, SPB, Facilities) • G. Dalton (SPB, EFI GSE ME), K. McKee (ME), S. Martin (MT) • R. Duck (AXB ME) • D. Schickele (Preamp, Sensor Cables, Facilities ME) • S. Grimmer, R. Gupta (ME GSRs) • S. Jelinsky, S. Marker (Facilities and TVAC Staff) • S. Harris (BEB Lead EE), H. Richard (BEB EE) • J. Lewis, F. Harvey (GSE) • Technical Staff (H. Bersch, Y. Irwin, H. Yuan, B. Dalen, N. Castillo) Wm. Greer (UCLA), et al.) • R. Ergun (DFB Co-I; CU-Boulder) • J. Westfall, A. Nammari, K. Stevens (DFB SysE, EEs; CU-Boulder) • C. Cully (DFB GSR; CU-Boulder)

  4. EFI Status at I-CDR • Requirements and Design: • The current EFI design meets Mission and Instrument requirements. • The design is complete. • One new requirement (CG positioning) has been imposed post-PDR. • Procurement: • All long-lead items have been procured in sufficient quantities to allow for ETU and initial FLT production: • EEE parts ordered; rad testing of required parts complete. • SPB and AXB mechanical items (custom wire cable, stacers, actuators, motors) are in-house, or on order with expected delivery on schedule for FLT build up. • FLT machining on order, with expected 25% fulfilment (1-1/2 SC of parts) by early July, and remainder by end of July. • Personnel: • Team is complete: • All design engineering positions filled. • One FT MT position filled Mar ’04; 0ne PT MT positions filled internally by personnel transitioning over from STEREO; two ME GSRs hired for summer and fall to support FLT production startup. • Assembly and Test: • ETUs of all major elements have been assembled and partially or largely tested. • Testing will be completed by July 2004.

  5. RFA and Design Trade Closure • RFAs from I-PDR, M-PDR, and I-CDR all responded to a/o closed out: • ESC Spec is on Rev. D1; includes detailed specs on the requirement and methods to achieve it; ESC roster developed in Feb ’04, allowing close collaboration between Swales and UCB on problem areas and mitigation techniques. • EMI Spec completed Mar ’04. • Detailed Instrument I&T plan under development as part of ETU Testing; synthesized from Polar, Cluster, etc. • Mechanical (INST-RFA 13, 14, 15, 19, 20, R03), and Electrical (INST-RFA 16AB, 17) arising from ICDR, as well as Internal Mechanical Review. • Open Design Trades from PDR closed out: • Boom lengths set at 50/40/7.67 meters tip-to-tip based on CBE of Probe mass properties and std. GSFC and UCB dynamic stability requirements and boom mode resonance keep-outs. • Ti-N chosen over DAG-213 for SPB sensor coating. • Heritage brushed motor chosen for SPB deploy. • Braid biasing selected, and Distal Braid length set at 3 m. • DAC implementation on BEB chosen (ADC5544), and bias offset range of +/- 40 V maintained. • EFI filters on DFB chosen to be Bessel-type.

  6. Mission Requirements

  7. Mission Requirements

  8. Mission Requirements

  9. Science Requirements

  10. Performance Requirements

  11. Performance Requirements

  12. EFI Board Requirements

  13. EFI Board Requirements

  14. EFI Boom Requirements

  15. EFI Block Diagram • A High-Input Impedance Low-Noise Voltmeter in Space sheath sensor preamp Floating ground generation BIAS USHER Bias channels GUARD VBraidCtrl VBraid BRAID Vref

  16. Top-Level Design (1) • Diagram of THEMIS EFI Elements AXB Preamp Enclosure Preamp PWB BEB SPB DFB GSE

  17. Top-Level Design (2) • Description of THEMIS EFI Elements • Three-axis E-field measurement, drawing on 30 years of mechanical and electrical design heritage at UCBSSL. • Closest living relatives are Cluster, Polar and FAST, with parts heritage from CRRES (mechanical systems, BEB designs, preamp designs).

  18. Top-Level Design (3) • Description of THEMIS EFI Elements • Radial booms: • 22-m cable length (up to 50 m tip-to-tip deployed; SPB-X to be deployed to 50 m, SPB-Y to be deployed to 40 m). • 8-cm dia., Ti-N-coated spherical sensor. • 3-m, 0.009-inch dia. fine wire to preamp enclosure. • SMA-actuated door release mechanism. • Brushed motor design. • Significant volume and mass relief relative to closest living relatives. • USHER and GUARD bias surfaces integral to preamp enclosure. • BRAID bias surface of 3-m length inboard of preamp (common between all 4 radial booms). • Sensor is grounded through 10 Mohm resistance when stowed, providing ESD protection and allowing for internal DC and AC functional tests. • External test/safe plug (motor,door actuator,turns click, ACTEST) to allow for deploy testing/safeing and external signal injection.

  19. Top-Level Design (4) • Description of THEMIS EFI Elements • Axial booms: • 2.8-m stacer with ~1-m DAG-213-coated whip stacer sensor. • New, fully-qualified Double DAD design based on FAST axial booms. • New, fully-qualified FrangiBolt deployment actuation. • Preamp mounted in-line, between stacer and sensor. • USHER and GUARD bias surfaces integral to preamp enclosure. • No BRAID bias surface. • Sensor is grounded through 7 Mohm resistance when stowed, providing ESD protection and allowing for internal DC and AC functional tests. • External test/safe plug (deploy actuator, ACTEST) to allow for deploy testing/safeing and external signal injection.

  20. Top-Level Design (5) Description of THEMIS EFI Elements • BEB block diagram:

  21. Top-Level Design (6) • Description of THEMIS EFI Elements • BEB Signal Processing and Control Specifications:

  22. Top-Level Design (7) Description of THEMIS EFI Elements • DFB functional block diagram:

  23. Top-Level Design (8) Description of THEMIS EFI Elements • DFB signal flow block diagram:

  24. Top-Level Design (9) • Description of THEMIS EFI Elements • DFB Signal Processing and Control Requirements: • +/- 100 V analog input relative to AGND. • CMRR >= 80 dB on differential E-Field channels. • DC-coupled E-fields and sensor potential waveforms from 0-4 kHz. • AC-coupled E-fields from 0-6 kHz. • AC-coupled SCM (AC B-field) from 0-4 kHz. • Log(AKR POWER) from 100-500 kHz. • E-field and sensor potentials for on-board Spin Fit data processing. • Filter bank with df/f better than 25% from 8 Hz to 4 kHz. • On-board projection of E and dB into ExB/E.B coordinates for FFT processing (“Derived Quantities”). • On-board computation of FFT spectra (Standard and Derived Quantities).

  25. Top-Level Design (10) • Performance Specification • Spacecraft potential: +/- 60 V, 1.8 mV resolution, better than 46 uV/m resolution (allows ground reconstruction of E from spacecraft potential to better than 0.1 mV/m resolution). • DC-coupled E-field: +/- 300 mV/m, 9 uV/m resolution, 0-4 kHz. • AC-coupled E-field: +/- 50 mV/m, 3.0 uV/m resolution, 0-6 kHz. • AKR log(Power) channel: 1 uV/m to 4.5 mV/m RMS amplitude, 400-kHz bandwidth, 100-500 kHz. • 16-bit resolution.

  26. Top-Level Design (11) • Thermal Predicts: 60-min-long eclipse 180-min-long eclipse

  27. Error Budgets • DC (ie. spin frequency or less): • Mechanical and Electrical design chosen to keep individual sources of systematic error on SPBs less than 1.0 mV/m: • CMRR of differential E-field channels >= 80 dB. • DC Gain within a few parts in 1000 of 1.0; better than 1% component matching then ensures CMRR >= 80 dB. • ESC requirements on potential uniformity and area of freely-charging exposed surfaces (eg. Insulators). • Different boom lengths (40 and 50 m) chosen to allow detection of systematic errors due to wake and boom shorting effects. • Fine wire length reduces shorting effect to 5% or less. • Improved Preamp Mechanical design reduces differential photocurrent collection by factor of 3-10 relative to Cluster-II (3 sufficient). • Increased requirement on CG placement accuracy to ensure alignment of boom pairs to better than 0.5 degrees (see detail, next slide). • AXB error budget more liberal, due to shorter length (errors scale as 1/L to 1/L3), and lack of Mission Requirement; few mV/m: • 4-cm control of +Z/-Z boom lengths to counteract shift of electrical center along spin axis (antenna mast vs. separation ring). • ESC requirements (AXB measurements will provide for a sensitive test of ESC compliance on-orbit).

  28. CG Placement Requirement • CG Offset Effect on Systematic Error in Sunward E-Field: • Center-of-Gravity (CG) offset from center of SPB boom system drives angular offset between opposing fine wires. • Opposing fine wires go through sun-alignment at different spin phases, leading to systematic bipolar error signal. • Primary effect is on instantaneous sunward E-field component. • CG positioning Requirement of 1 part in 100 of SPB Cable pivot radius (approx. 4 mm, or 0.166 inch) drives magnitude of error below 0.8 mV/m, worst-case. (CG offset)/(pivot radius) 0.01 0.001

  29. Error Budgets • EFI Spectral Coverage and System Noise Estimates Maximum Spectra (DC-Coupled) 1/f3 1/f flat CDI BBF AKR band 1-LSB Spectra (DC-Coupled) Preamp and Rbias Current Noise Preamp Voltage Noise axial radial 10-Hz Ac-coupled roll-in Spin frequency 4-kHz Anti-aliasing roll-off

  30. Error Budgets • RE02 BB Limits set to give S/N of > 3 for expected AKR amplitudes. • RE02 NB limits set to drop equivalent BB spectral density below expected amplitudes below 4 kHz on SPB.

  31. Error Budgets • 7.5 pF input capacitance of preamp has significant effect on gain above 100 Hz: • SPB AC gain is 0.65. • AXB AC gain is 0.45. • Rolloff frequency from DC to AC gain (resistive to capacitive coupling) is predominantly controlled by sheath resistance, which is under direct control via sensor bias current. • AC gain in both cases is still sufficient to achieve required measurements over desired frequency interval.

  32. EFI Subsystem Design, Fabrication, and Test Status

  33. Assembly and Test To-Date • ETUs • AXB (1 unit): assembled March ’04; RT and TVAC deploy tested, March ’04; redesigned, rebuilt, redeployed April ’04; Sensor redesign, May ’04; Straightness, May ’04; Horiz. Deploy (length cal), June ’04. • SPB (1 unit): assembled April ’04; Housing, Door, and Door Actuator redesigned and rebuilt May ’04; vibe’d June ’04; TVAC and RT Deploy, June ’04. • Preamp Enclosure: Four ETUs built, April, ’04 and integrated into ETU Cables, SPB, and AXB; Cable termination redesigned, May ’04 (post-I-CDR); revised ETUs to be built June ’04. • Cables: One Prototype, two ETU Sensor Cables, and one special Thermal Cable fabricated March 29 – April 9, ’04; integrated with ETU Preamp PWBs and ETU SPB and AXB for vibe testing, and Preamp Thermal Model Simulator.

  34. Assembly and Test To-Date • ETUs (con’t) • Preamp PWB: Two ETU Preamp PWB assembled April 9 ’04; integrated with ETU Preamp PWBs and ETU SPB and AXB for vibe testing. One Flight-like PWB assembled for Preamp Thermal Modeling (nominal operation at –130 C!). • BEB: One ETU built, Mar ’04; functional testing, Mar-Apr ’04, design qualified, meets required specifications; Integrated BEB-Preamp-Cable testing ongoing, June ’04. • DFB: One BB ETU with core FPGA functionality (CDI interpreter, waveform filters and filter banks) completed mid-May ’04; successfully integrated with BEB, DCB, and EFI/BEB EGSE, mid-May ’04; true ETU fab and assy late June-early July ’04.

  35. Assembly and Test To-Date • GSE and Harnessing • EGSE: BEB/EFI Electrical GSE complete and characterized, April ’04; spare unit with reduced fuctionality to support BEB Flight Board Testing, on-order, June ’04. • Faraday Boxes: two Faraday boxes with internal fixtures and wiring (signal paths and Plasma Simulators), complete, June ’04. • MGSE: AXB TVAC fixtures done; AXB FrangiBolt simulator done; AXB HDeploy Track, TBC, June ’04; SPB TVAC Takeup Reels, TBC, June ’04 for SPB TVAC; SPB TVAC Fine Wire Deploy Reels, TBC, June ’04. • TVAC Harnessing: design complete, April-May ’04; SPB ETU built, May ’04; AXB to be built, July ’04. • ETU Harnessing: design complete, May ’04; under fabrication to support II&T, June ’04. • Misc. Test Harnessing: dual boom unit Y-Test Harness, built May ’04. Breakout boxes, etc., designed and built as needed.

  36. Near-Term Testing • Mechanical • AXB and SPB Vibe (June 9 and 10) – units passed. • SPB TVAC (Deploy Testing) (June 18-25; pending completion of B20 “Bayside” refurbishment), AXB TVAC complete and successful. • AXB and SPB Deploy Calibrations (late June). • Testing required to support FLT machining orders complete. • Thermal • Long-Eclipse Thermal Simulation and Thermal Shock (aka. L-N2 Dunk) for Preamp, -130 C to 60 C (May 2004; July 2004) • Electrical • Integrated electrical testing of EFI and BEB (all of June 2004; EFI/BEB EGSE complete; Faraday Boxes complete in late April). • Formal Preamp Thermal Qualification (TVAC cycles and DPA) (Jul-Aug 2004, parallel with F1 FLT build). • Suite-Level Testing (II&T) • EFI ETU delivered to II&T July 2004.

  37. Parts Procurement, Qual, and Contamination • Long-Lead Items • All long-lead items in-house or on schedule for delivery to support July ’04 start of Flight production. • Custom Cable • SPB Flight motors, bearings, slip rings, machine parts. • AXB Flight stacers, bearings. • Preamp Enclosure machine parts and Cable Fab fixtures. • BEB parts kits. • DFB parts kits. • Preamp parts kits. • Qualification Testing • All parts passed radiation (AD5544 DAC and LTC1604 ADC, in particular). • Formal qualification of Preamp OP-15 and design via TVAC and DPA in parallel to ETU and Initial Flight Build (July ’04). • Contamination • All suspect parts sent to UCLA for magnetic characterization (eg. SPB motors and geartrain).

  38. EFI Integration and Test Plans

  39. Facilities • ETU Testing • Refurbished UCBSSL Silver B20 “Bayside” TVAC Chamber • Accommodates up to 4 SPB. • UCBSSL Addition High Bay “Geoffrey” TVAC Chamber • Accommodates fully-deployed AXB vertically. • Vibe Testing done off-site. • AXB Horizontal Deploy Track. • SPB Vertical Deploy Fixtures in High Bay • Alternately, Std. Horizontal Deploy in SSL “Dungeon”. • FLT Testing • Same facilities as ETU, plus: • New UCBSSL Silver B20 “EFI Snout” TVAC Chamber • Accommodates fully-deployed AXB horizontally. • Vibe testing done off-site.

  40. Calibration and Test • Mechanical and Electro-Mechanical • SPB Deploy Length • Turns Count • Deploy Rate • SPB Door Actuation and Function • AXB Deploy Length • Repeatability • Stiffness and Straightness • SPB Door SMA and AXB Deploy FrangiBolt Currents • SPB and AXB Cable Continuity and Isolation during Deploy • Electrical • EFI/BEB Calibration • Quiescent and Operational Currents • DC Functional Tests (Gain, Offset, CMRR, Linearity, 0.1% Matching) • AC Functional Tests (Transfer Function, CMRR, Slew Rate, Linearity) • EFI/SCM/FGM via DFB Phase Intercalibration • See Suite-Level I&T.

  41. Assembly and Test Flow SPB Assembly and Test Flow, based on ETU Experience:

  42. SPB Assembly and Test Plan

  43. SPB Assembly and Test Plan

  44. Instrument (Suite) I&T Plan • Integration and Test • Instrument I&T takes place at UCBSSL. • Environmental (TVAC, Vibe, Suite EMC as per THM-SYS-005 Environmental Verification Spec). • Limited and Comprehensive Performance Testing: • SPB Motor Simulators (aka. Motor-in-a-Box) and AXB Test FrangiBolts (aka. FrangiBolt-in-a-Box) used for pre- and post-environmental functional tests of deploy mechanisms, as well as dummy electrical loads during “fake” TVAC deploy testing. • Internal DC and AC functional test capability used for pre- and post-environmental functional tests of sensors; sensors may be directly stimulated via ACTEST line on Test/Enable plug. • End-to-End SPB and AXB TVAC Deploy Testing (IDPU-controlled; Motor-in-a-Box and FrangiBolt-in-a-Box). • Integrated Fields System (DCB, DFB, EFI, SCM, FGM) modes testing: Nominal, Slow, Fast, Torturous Data Exchange, and “Mode X”. • Phase intercalibration between EFI, SCM, and FGM performed using EFI Test/Enable Plugs, SCM Mu-Metal Box, FGM TCU and 12-channel, 16-bit, +/- 10-V National Instruments DAC system.

  45. S/C (Probe) I&T Plan • Integration and Test • Probe I&T takes place at Swales Aerospace. • Environmental (TVAC, Vibe, Shock, EMI; as per THM-SYS-005 Environmental Verification Spec). • Limited and Comprehensive Performance Testing: • Sensors via internal DC and AC Functional Test capability, monitored through ITOS. • Actuators via external Boom Loads Simulator (BLS) and Test/Enable plugs, monitored through ITOS. • Sensors may be stimulated externally via breakout on BLS, if required (non-standard test). • Initial ITOS requirements outlined, Apr 2004. • Red/Green tag items: • One red tag Snout Cover per SPB (4 total). • One red/green Test/Enable plug per SPB (4 total). • One red tag Tube Cover per AXB (2 total). • One red/green Test/Enable plug supporting both AXBs (1 total)

  46. EFI Production Schedule

  47. F1-F2 Production Schedule SPB Cables Vibe TVAC, RT Preamp 13 Sep ‘04 AXB 5 Jul ‘04 BEB Cals 4 Oct ‘04 26 Jul ‘04

  48. FLT Production Schedule • Grassroots estimate, based on ETU experience (1 person-day/subassy, TVAC and RT testing experience, electrical checkout, etc.). • Subassembly Assy tasks (eg. SPB Motor, Spool, etc.) carry 100% margin. • Rate setting steps are Mechanical Test and BEB Board Test (3-week durations). • 3-week delivery cadence, with 2-week overlap between Fn Boom Assy and Fn+1 Subassembly Assy work. • 5-week delivery cadence removes all overlap between successive Boom and Subassembly Assy work. • Downstream schedule risk will be reduced by using Subassembly schedule margin and larger summer labor pool (F1) (GSRs) to lay in overstock for F2 through F6. • Dedicated TVAC personnel (Jelinsky, McKee, Marker) used to reduce schedule risk from spreading Engineering staff thinly between Assembly, Test, and I&T.

  49. EFI Mission Operations

  50. Deploy and Commissioning • Draft Deploy and Commissioning plan developed Nov 2003. • Draft plan refined Mar 2004 in response to revised launch date (21 Aug -> 21 Oct 2006). • EFI SOH to be determined on all probes using stowed DC and AC functional test capability during initial on-orbit check-out. • Instrument SOH used to determine probe assignment. • EFI deployed on all probes after placement in initial science orbits. • EFI deployed in 6 to 7 steps: • 5 to 6 intermediate deploy lengths with spin up for SPB. • 1 step to deploy both AXB. • Primary constraints on deploy and commissioning: • 1 30-minute TM contact per 3-1/2 hours (thermal). • Desire to gather science data at intermediate deploy lengths and in different plasma regimes.

More Related