GP-B Post-Flight AnalysisÃ¢Â€Â”Final Report - Gravity Probe B - Stanford ...

More documents

Recommendations

Info

DateSeverity40 11-May-04 Obs T Dwell scan aborted Dwell scan aborted due toATC mis-configuration of rollrate41 11-May-04 Obs T High He Mass Flowduring drag-free42 12-May-04 Obs T TRE +XA Ch Clipping/ATCdwell Scan issue43 12-May-04 Obs T Change of rotor chargeafter high-voltagecheckout44 13-May-04 Medium CSS reasonablenesssafemode activated45 13-May-04 Obs O Misconfiguration AFTversus FWD antennaSubtypeTitle Description Root cause Corrective ActionHigh He Mass Flow duringdrag-free (as observed bydewar telem)TRE +XA channel clipping.Change of rotor charge afterhigh-voltage checkout ongyros 4 & 1Coarse Sun Sensorreasonableness testtriggered safemode:stopped timeline, switchedto ACE B, safed GMA valves,reconfigured COM to125/1K.Following A-044, AFT andFWD transmitters weremisconfigured.46 14-May-04 Obs F Double-bit error tracking No automatic method oftracking double bit errors.47 14-May-04 Obs F Science Gyro 2 Largeposition excursion seenwith shutter activation48 16-May-04 Obs T Dewar main Tank temprising faster thanexpected during fluxflushScience Gyro2 Largeposition excursion seen withshutter activationDewar main Tank temprising faster than expectedduring flux flushAbort due to momentarilyexceeding commandedmass flow with combinationof drag-free and roll-downmaneuver.Thruster biases.DMA balance algorithm notgenerating a good balancesolution.Field emission of electronsin HV configuration withrotor off-center.CSS reasonablenessalgorithm misinterpretedsun sensor data as SV wentfrom full sun to eclipseperiod.Operations misconfiguationoftranspondersTemplates not available aspart of pre-launch set.Shutter generating largerthan anticipated mechanicaltransient.Larger than expected gas inwell between probe anddewar.Adjust mass flow limits toallow for sufficient massflow or separate dwell scanand drag-free maneuvers.Update thruster biases toeliminate excess mass flow.Update algorithm andredeliver.Discharge rotor andcontinue tests.Disable SM response;modify VMS macros to onlyuse/look at CSS in ATCbackup modes. VMSmacros updated followingFSW 3.4.3 upload.Explicit commands in loadare now used to commandthe transponders on andoff.Develop and delivertemplates to perform DBEmonitoring.Do not use shutter;abandon in place.Increase null dump tomaintain dewartemperature.530 March 2007 Chapter D — Summary Table of Flight Anomalies
DateSeveritySubtypeTitle Description Root cause Corrective Action49 17-May-04 MAJOR SM activated - High bodyratesHigh body rates observed(pointing) that activatedsafemode following fluxflush. Significant attitudeexcursions observed over anumber of days, degradingcommunications.Thruster 8 failed during highflow conditions followingflux flush. Failed openthruster caused porous plugto choke prior to thruster 8isolation. Most likely rootcause is foreign objectcontamination of thruster 8.Disable Thruster 8 (via TIV).Rebuild and reload ATCcontroller (FSW) to thrusterselection algorithm tocompensate for loss ofthrusters 6, 8. Update andinstall related VMS macros.50 18-May-04 Obs N Vatterfly valve stateupon SM (Anomaly #49)entry changed to closed,but we believe the valveremained openVatterfly valve state uponSM (Anomaly #49) entrychanged to closed, but webelieve the valve remainedopenFeature of ECU telemetrysampling scheme.Non-issue51 20-May-04 Obs T GSS low voltagecheckout failed tocomplete on Gyros 2 & 3Preliminary analysis oftelemetry indicates GSS lowvoltage checkout failed tocompleteHigh gyro charge from initiallevitation off wall (300 mV)Discharge rotor andcontinue tests.52 20-May-04 Obs T Dewar micro-tempvariation at orbital androll period53 21-May-04 Obs T GSS2 reduced stabilitymargins during uncagedcheckoutDewar micro-temp variationat orbital and roll periodResidual thermal couplingto probe from environmentAdjust tank temperatureand watch.Indications of reducedstability margins of sciencegyro 2 during uncagedcheckoutInsufficient stability marginfor gyro 2 at originalmodulation frequency,possibly due todisconnected ground planeIncrease frequency of drivevoltage from 20 to 30 Hz.54 25-May-04 Minor Unexpected turn off ofgyro1 High VoltageGyro1 de-levitatedunexpectedly during Gyro2suspension operation. Thegyroscope was not spinningat a significant rate at thispoint in the mission.Template error; a templatecloning error left the Gyro 1HV off commands in all fourgyro’s “science mission presuspend”templates. ITF hadinsufficient fidelity to detectthis error when tested.100% review of all GSStemplates (~250 items) forcloning errors or misplacedcommands. Correct anyerrors found, retest.Gravity Probe B — Post Flight Analysis • Final Report March 2007 531
Page 1 and 2:
Post Flight Analysis — Final Repo
Page 3 and 4:
Signatures & ApprovalsPrepared byPu
Page 5 and 6:
Table of ContentsPreface . . . . .
Page 8 and 9:
6.8 Sources and References . . . .
Page 10 and 11:
11 Telescope Readout Subsystem (TRE
Page 12 and 13:
14 Data Collection, Processing & An
Page 14 and 15:
xiv March 2007 Table of Contents
Page 16 and 17:
Figure 3-4. The GP-B dewar—one of
Page 18 and 19:
Figure 8-5. The Seasons of GP-B . .
Page 20 and 21:
Figure 11-20. Pointing angle differ
Page 22 and 23:
Figure 14-9. In the Anomaly Room, t
Page 24 and 25:
xxiv March 2007
Page 26 and 27:
Table 13-3. GP-B payload magnetomet
Page 28 and 29:
xxviiiMarch 2007
Page 30 and 31:
2 March 2007 Chapter 1 — Executiv
Page 32 and 33:
facility, it was necessary to recas
Page 34 and 35:
spacetime around with them as they
Page 36 and 37:
After years of work and the inventi
Page 38 and 39:
axis of a gyroscope rotor changes i
Page 40 and 41:
Figure 1-8. Clockwise, from top lef
Page 42 and 43:
“management experiment.” This w
Page 44 and 45:
Attitude-Control Gyroscopes. Two pa
Page 46 and 47:
Any significant deviation from “g
Page 48 and 49:
established, ranging from Level 1 (
Page 50 and 51:
1.14 The Broader Legacy of GP-BAt l
Page 52 and 53:
24 March 2007 Chapter 2 — Overvie
Page 54 and 55:
Figure 2-1. GP-B Historical Time Li
Page 56 and 57:
Applied Physics Laboratory, of the
Page 58 and 59:
William Fairbank once remarked: “
Page 60 and 61:
In Einstein’s view, space and tim
Page 62 and 63:
y a mere 1.1 inches. You can see th
Page 64 and 65:
Figure 2-10. Schematic diagram of t
Page 66 and 67:
Figure 2-12. Final assembly of the
Page 68 and 69:
Sun Shield. The sun shield is a lon
Page 70 and 71:
2.1.8 The Broader Legacy of GP-BWhe
Page 72 and 73:
2.3 Spacecraft SeparationThe Solar
Page 74 and 75:
Flight Anomalies.) Furthermore, a d
Page 76 and 77:
Table 2-2. Weekly summary of IOC ac
Page 78 and 79:
2.4.3.2 Guide Star AcquisitionAbout
Page 80 and 81:
A second mass trim operation had be
Page 82 and 83:
On Friday, 2 July 2004, the spin ra
Page 84 and 85:
Low temperature bakeout was first p
Page 86 and 87:
2.5.1.3 Lockheed Martin Team Phase-
Page 88 and 89:
Monthly Highlights of the GP-B Scie
Page 90 and 91:
2.6.1 Overview of the Calibration P
Page 92 and 93:
Weekly Highlights of the GP-B Final
Page 94 and 95:
66 March 2007 Chapter 3 — Accompl
Page 96 and 97:
It was in this pristine, near-zero
Page 98 and 99:
Each quartz rotor is coated with a
Page 100 and 101:
Figure 3-3. Functional diagram of a
Page 102 and 103:
Based on data from the on-board tel
Page 104 and 105:
Ideally, the telescope should have
Page 106 and 107:
Figure 3-9. Schematic diagram of st
Page 108 and 109:
used. The star trackers are essenti
Page 110 and 111:
Result: By using the porous plug, w
Page 112 and 113:
Solution: Create a tetrahedral lapp
Page 114 and 115:
Constraint 2: The exhaust tube must
Page 116 and 117:
Result: The on-orbit gyroscope spin
Page 118 and 119:
spacecraft's subsystems for the dur
Page 120 and 121:
Constraint 3: Keep the spacecraft p
Page 122 and 123:
Technology Category Specific Implem
Page 124 and 125:
96 March 2007 Chapter 4 — GP-B On
Page 126 and 127:
Any significant deviation from “g
Page 128 and 129:
packages, one for each Ping load an
Page 130 and 131:
In addition to these software packa
Page 132 and 133:
Table 4-6. Features & benefits of W
Page 134 and 135:
This software added considerable ef
Page 136 and 137:
It is said that “an experiment is
Page 138 and 139:
Table 4-10. Significant Events/Sour
Page 140 and 141:
Figure 4-5. Pictorial depiction of
Page 142 and 143:
Figure 4-7. Eta-Average Error Assoc
Page 144 and 145:
4.4.4.2 OD Using SLR DataFigure 4-9
Page 146 and 147:
4.4.5 ConclusionsFigure 4-11. Compa
Page 148 and 149:
Overall, the storage issues did not
Page 150 and 151:
Table 4-11. ITF equipment listEQUIP
Page 152 and 153:
124 March 2007 Chapter 5 — Managi
Page 154 and 155:
5.2 Overview of GP-B Anomalies in O
Page 156 and 157:
Figure 5-1. Anomaly Review Team Org
Page 158 and 159:
5.3.3.1 Anomaly Investigation and R
Page 160 and 161:
5.3.5 Anomaly Identification and Re
Page 162 and 163:
5.4.3 Risk Management ApproachThe r
Page 164 and 165:
Table 5-1. Summary of Open GP-B ris
Page 166 and 167:
138 March 2007 Chapter 5 — Managi
Page 168 and 169:
140 March 2007 Chapter 6 — The GP
Page 170 and 171:
3. Payload Integration, Testing and
Page 172 and 173:
Figure 6-1. Clockwise from top left
Page 174 and 175:
MSFC conducted an in-house Phase A
Page 176 and 177:
It is important to note that from t
Page 178 and 179:
6.3.1 Incremental PrototypingThe pe
Page 180 and 181:
alignment, and act as an accelerome
Page 182 and 183:
Figure 6-9. The Lockheed Martin GP-
Page 184 and 185:
Furthermore, a fourth electronic sy
Page 186 and 187:
positive thermal connections betwee
Page 188 and 189:
astrophysics/cosmology. Many of the
Page 190 and 191:
Figure 6-10. MSFC Program Managers/
Page 192 and 193:
As described in Chapter 2, the flig
Page 194 and 195:
6.7 Some Observations on the Manage
Page 196 and 197:
168 March 2007 Chapter 6 — The GP
Page 198 and 199:
170 March 2007 Chapter 7 — Attitu
Page 200 and 201:
7.1.2 Vehicle ATC ModesThere are es
Page 202 and 203:
The output of the pressure transduc
Page 204 and 205:
Figure 7-3. Science Telescope Compo
Page 206 and 207:
Figure 7-5. Pitch and Yaw Pointing
Page 208 and 209:
Figure 7-7. Magnitude of the roll r
Page 210 and 211:
Changing the method by which the gy
Page 212 and 213:
7.3.3 Drag-Free Control SystemFigur
Page 214 and 215:
7.3.3.1 DFS - PerformanceThe GP-B d
Page 216 and 217:
Figure 7-15. Mass flow effects of a
Page 218 and 219:
7.5.2 Successful recovery from mult
Page 220 and 221:
If the vehicle control system were
Page 222 and 223:
accomplish this, the ARPs are mount
Page 224 and 225:
7.5.6.1 South Atlantic AnomalyProto
Page 226 and 227:
Figure 7-23. Effects on telescope p
Page 228 and 229:
200 March 2007 Chapter 7 — Attitu
Page 230 and 231:
202 March 2007 Chapter 8 — Other
Page 232 and 233:
Figure 8-2. Block Diagram of CDH co
Page 234 and 235:
8.1.1.4 WATCH DOG TIMERFigure 8-4.
Page 236 and 237:
of eclipses each day (approximately
Page 238 and 239:
Figure 8-8. GSS1 Temperature Trends
Page 240 and 241:
Figure 8-10. Forward Dewar Vacuum S
Page 242 and 243:
The Gravity Probe B spacecraft has
Page 244 and 245:
Figure 8-13. Forward -X Thruster Te
Page 246 and 247:
gaFigure 8-15. Aft -X Thruster Temp
Page 248 and 249:
Because there are only two SQUID br
Page 250 and 251:
Because the specifications for SRE
Page 252 and 253:
8.3.2 Critical Mission RequirementT
Page 254 and 255:
Figure 8-19 is a plot of the power
Page 256 and 257:
Battery Performance Summary:Figure
Page 258 and 259:
Figure 8-23. Solar Array Temperatur
Page 260 and 261:
8.3.10 ConclusionThe electrical pow
Page 262 and 263:
8.4.1 TDRSS OperationsFigure 8-28.
Page 264 and 265:
Figure 8-30. Xpndr-A STDN (green),
Page 266 and 267:
Figure 8-32. Plot of TDRS AGC vs Te
Page 268 and 269:
The FSW also met its subsystem leve
Page 270 and 271:
Appendix E, Flight Software Applica
Page 272 and 273:
Table 8-4. SCRs Addressed in On-orb
Page 274 and 275:
The software and macro changes resu
Page 276 and 277:
Figure 8-38 below is an excerpt fro
Page 278 and 279:
Figure 8-40. A-side CCCA Single Bit
Page 280 and 281:
Figure 8-43. A-side CCCA Single Bit
Page 282 and 283:
When single MBEs did not result in
Page 284 and 285:
256 March 2007 Chapter 9 — Gyro S
Page 286 and 287:
9.1 GSS Hardware DescriptionFigure
Page 288 and 289:
significantly reduces and thus pres
Page 290 and 291:
9.1.11 Clock synchronizationThe aft
Page 292 and 293:
Figure 9-8. Block diagram of the LQ
Page 294 and 295:
direction (transverse to the space
Page 296 and 297:
9.2.2.2 Spin-up SuspensionDuring sp
Page 298 and 299:
Figure 9-16. Predicted and measured
Page 300 and 301:
Figure 9-18. The GSS passes rotor c
Page 302 and 303:
Figure 9-20. Representative drag-fr
Page 304 and 305:
Table 9-1. GSS Science Mission Mode
Page 306 and 307:
Table 9-3. GSW application source l
Page 308 and 309:
The Design and Testing of the Gravi
Page 310 and 311:
282 March 2007 Chapter 10 — SQUID
Page 312 and 313:
ate uncertainty). Although we have
Page 314 and 315:
All of the GP-B electronics have be
Page 316 and 317:
10.3 Pre-Launch Ground-Based TestsW
Page 318 and 319:
Figure 10-6. AC Magnetic Shielding
Page 320 and 321:
Figure 10-8. Temperature Error of S
Page 322 and 323:
Figure 10-10. Quiescent SQUID Noise
Page 324 and 325:
Analog control loops on the electro
Page 326 and 327:
The science support applications ru
Page 328 and 329:
Table 10-7. SSW application source
Page 330 and 331:
Page 332 and 333:
Page 334 and 335:
Page 336 and 337:
308 March 2007 Chapter 11 — Teles
Page 338 and 339:
Figure 11-1. Block diagram of TRE a
Page 340 and 341:
Additionally, the warm electronics
Page 342 and 343:
Figure 11-3. CLL switch states duri
Page 344 and 345:
Table 11-3. Dates and UTC times whe
Page 346 and 347:
Figure 11-7. Low Gamma Angle Data S
Page 348 and 349:
s N+w i= sign+w i++−+−w i−w i
Page 350 and 351:
expression, which otherwise on a po
Page 352 and 353:
Figure 11-14. Y axis, B side RMS po
Page 354 and 355:
Figure 11-17. X axis, B side curren
Page 356 and 357:
Figure 11-20. Pointing angle differ
Page 358 and 359:
Figure 11-24. Scaled summed current
Page 360 and 361:
Figure 11-26 through Figure 11-29 s
Page 362 and 363:
334 March 2007 Chapter 12 — Cryog
Page 364 and 365:
12.2 Temperature / pressure control
Page 366 and 367:
control the space vehicle without t
Page 368 and 369:
Figure 12-3. Helium flow rate predi
Page 370 and 371:
helium at 1.8 K. It does not appear
Page 372 and 373:
Figure 12-6. Flow meter and ATC flo
Page 374 and 375:
were generally within a day or so o
Page 376 and 377:
shields) and subsequent instability
Page 378 and 379:
350 March 2007 Chapter 12 — Cryog
Page 380 and 381:
352 March 2007 Chapter 13 — Other
Page 382 and 383:
Figure 13-2. ECU-operated heaters i
Page 384 and 385:
13.1.3.1 Vatterfly Valve Operations
Page 386 and 387:
13.1.3.7 Payload MagnetometersThe E
Page 388 and 389:
Figure 13-11. ECU performance durin
Page 390 and 391:
As we entered the second month of o
Page 392 and 393:
During the last month of IOC, prepa
Page 394 and 395:
Figure 13-19. ECU heater activity d
Page 396 and 397:
Table 13-1. Proton monitor channel
Page 398 and 399:
Figure 13-21. Proton Monitor data i
Page 400 and 401:
In November, 2004 there was a large
Page 402 and 403:
Figure 13-28 shows a correlation th
Page 404 and 405:
13.3.1 About the MagnetometersFigur
Page 406 and 407:
13.3.2 Other Applications for Paylo
Page 408 and 409:
Figure 13-35. GPS Antennae Field of
Page 410 and 411:
Figure 13-37. Master Antenna Switch
Page 412 and 413:
Figure 13-39. Time difference betwe
Page 414 and 415:
13.4.6 On-Orbit ResultsThe GPS comp
Page 416 and 417:
and velocity values erroneously cal
Page 418 and 419:
E. G. Lightsey, C. E. Cohen, B. W.
Page 420 and 421:
Figure 13-45. A Bottom View of the
Page 422 and 423:
Figure 13-48. The GMA configuration
Page 424 and 425:
Table 13-10. Summary for Helium Gas
Page 426 and 427:
398 March 2007 Chapter 14 — Data
Page 428 and 429:
a relatively slow data rate, so we
Page 430 and 431:
Figure 14-4. NASA ground stations a
Page 432 and 433:
electronic components to recover fr
Page 434 and 435:
By a process of elimination, the GP
Page 436 and 437:
A special room in the GP-B Mission
Page 438 and 439:
Starting on 3 December 1725, Bradle
Page 440 and 441:
seemed that aberration of starlight
Page 442 and 443:
14.1.6 Telescope Dither—Correlati
Page 444 and 445:
14.1.6.3 The Telescope Dither Patte
Page 446 and 447:
amplifications. Thus, in addition t
Page 448 and 449:
14.2.2 Independent Data Analysis Te
Page 450 and 451:
monthly time scales. Though only sh
Page 452 and 453:
424 March 2007 Chapter 15 — Preli
Page 454 and 455:
Figure 15-2. A diagram of the GP-B
Page 456 and 457:
15.4 The Two Surprises and Their Im
Page 458 and 459:
Near Zeroes.) The exception that we
Page 460 and 461:
Figure 15-8. A slide from the GP-B
Page 462 and 463:
Figure 15-9. A poster on the effect
Page 464 and 465:
electrostatic patches, located at o
Page 466 and 467:
Last summer (2006), Mac Keiser devi
Page 468 and 469:
440 March 2007 Chapter 15 — Preli
Page 470 and 471:
442 March 2007 Chapter 16 — Lesso
Page 472 and 473:
16.1.1.3 Flight science downlink da
Page 474 and 475:
Description of the GP-B experience:
Page 476 and 477:
Lessons:1. Perform all tests with a
Page 478 and 479:
Page 480 and 481:
Figure 16-1. Six interacting transl
Page 482 and 483:
16.1.3.2 Training and certification
Page 484 and 485:
Page 486 and 487:
Below is an edited summary of six a
Page 488 and 489:
460 March 2007 Chapter 16 — Lesso
Page 490 and 491:
462 March 2007 Appendix A — Gravi
Page 492 and 493:
Apogee altitude659.1 km (409.6 mile
Page 494 and 495:
466 March 2007 Chapter B — Spacec
Page 496 and 497:
Gravity Probe B — Post Flight Ana
Page 498 and 499:
470 March 2007 Appendix C — Weekl
Page 500 and 501:
16 April 2004—Vehicle is Prepared
Page 502 and 503:
The electrical power system is full
Page 504 and 505:
4 JUNE 2004—MISSION UPDATE: DAY 4
Page 506 and 507:
SQUIDs to detect their rotation spe
Page 508 and 509: 17 JULY 2004—MISSION UPDATE: DAY
Page 510 and 511: indicate that we have reduced the t
Page 512 and 513: C.4 Science Mission Phase: 8/27/04
Page 514 and 515: • GP-B also has an independent da
Page 516 and 517: free suspension parameters to de-tu
Page 518 and 519: We have received inquiries about a
Page 520 and 521: One of the effects of geomagnetic s
Page 522 and 523: egan transmitting, one-by-one, stat
Page 524 and 525: 28 JANUARY 2005—GRAVITY PROBE B M
Page 526 and 527: magnetic pole. This event triggered
Page 528 and 529: 8 APRIL 2005—GRAVITY PROBE B MISS
Page 530 and 531: On Tuesday afternoon (19-April), GP
Page 532 and 533: Norway or through the NASA space ne
Page 534 and 535: Dewar Temperature: 1.82 kelvin, hol
Page 536 and 537: visitors on a tour of the GP-B faci
Page 538 and 539: test, we are planning on running fi
Page 540 and 541: contractor at the Goddard Space Fli
Page 542 and 543: On Wednesday, we visited the star H
Page 544 and 545: Gyro Suspension System (GSS): All 4
Page 546 and 547: The helium in the dewar has now sur
Page 548 and 549: the all the spacecraft status data.
Page 550 and 551: 522 March 2007 Appendix D — Summa
Page 552 and 553: Figure D-2 below shows the distribu
Page 554 and 555: DateSeveritySubtypeTitle Descriptio
Page 556 and 557: DateSeverity24 26-Apr-04 Obs F Nois
Page 562 and 563: DateSeverity68 16-Jun-04 Medium Dec
Page 564 and 565: DateSeverity84 13-Jul-04 Obs F Slig
Page 568 and 569: DateSeverity116 26-Sep-04 Obs F SG3
Page 570 and 571: DateSeverity132 20-Dec-04 Obs F Unc
Page 572 and 573: DateSeverity149 5-Mar-05 Obs T Few
Page 574 and 575: DateSeverity169 04-Jun-05 Obs F MBE
Page 576 and 577: DateSeverity191 04-Oct-05 Obs A GSS
Page 578 and 579: 550 March 2007 Appendix E — Fligh
Page 580 and 581: ReqIDLevel 1CSCDMP DataMgmtProcessi
Page 582 and 583: ReqIDLevel 1CSCLevel2 CSC Level 3 C
Page 588 and 589: ReqIDLevel 1CSCSRM Solid StateRecor
Page 594 and 595: ReqIDLevel 1CSCSRP SafemodeResponse
Page 596 and 597: ReqIDLevel 1CSCGUP GSS Processing g
Page 598 and 599: 570 March 2007 Appendix F — Acron
Page 600 and 601: AcronymDefinitionAcronymDefinitionB
Page 602 and 603: AcronymDefinitionAcronymDefinitionD
Page 604 and 605: AcronymDefinitionAcronymDefinitionF
Page 606 and 607: AcronymDefinitionIRUInertial Refere
Page 608 and 609:
AcronymDefinitionAcronymDefinitionM
Page 610 and 611:
AcronymPMPMAPMCPMEPMETPMSPMSUPNPoPO
Page 612 and 613:
AcronymSCMOSCMTSCNSCPASCPMSCRSCSASC
Page 614 and 615:
AcronymDefinitionAcronymDefinitionT
Page 616:
588 March 2007 Appendix F — Acron
show all

GP-B Post-Flight AnalysisÃ¢Â€Â”Final Report - Gravity Probe B - Stanford ...

Create successful ePaper yourself

Delete template?

Save as template?