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

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C.4 Science Mission Phase: 8/27/04 - 8/12/0527 AUGUST 2004— GRAVITY PROBE B MISSIONUPDATE: DAY 129On Day #129, we have arrived at the second major milestone of themission—the completion of the Initialization and Orbit Checkout(IOC) Phase and transition into the Science Phase. The spacecraftcontinues to be in excellent health, with all subsystems performingwell. The telescope is properly tracking the guide star, IM Pegasi,during the portion of each orbit when the guide star is visible. Fineprecision spin axis alignment has been completed on gyros #1, #2, and#3, and after the suspension voltages on these gyros were reducedfrom 10 volts to 200 millivolts in preparation for data collection, a finalelectrostatic discharge was performed on the gyro rotors usingultraviolet light. Gyro #4 is further behind its fellow gyros and willcontinue undergoing spin axis alignment awhile longer. Today, thespacecraft was placed in a drag-free mode around gyro #3, and it willremain in this mode for the duration of the Science Phase of themission, which has now officially begun.Over the course of this past week, we completed a number of finaladjustments to the spacecraft and the gyros, in preparation for thetransition to the Science phase. For example, on Wednesday, August25th, we increased the spacecraft’s roll rate very slightly from 0.75 rpmto 0.7742 rpm. This moved the signal frequencies from the gyros outof the range of telemetry sample rate harmonics, thus improving thesignal to noise ratio of the experimental data.Throughout most of this past week, we continued fine precisionalignment of the gyro spin axes to the telescope axis. Conceptually,this is a straightforward process. Our SQUID magnetometers, inconjunction with the Gyro Suspension System (GSS), can detect veryslight imperfections in the gyro rotors, and they utilize theseimbalances, enhanced by a suspension force of 10 volts (50 timeshigher than the science suspension voltage of 200 millivolts) to torquethe rotors ever so slightly, causing their spin axes to spiral in towardsthe target alignment position. However, our success in creating gyrorotors that are almost perfect spheres actually hinders this process.The smaller the level of imperfections in the rotors, the longer it takesthe GSS to complete the alignment.Today, we completed the final preparations, prior to beginning datacollection. First, we reduced the suspension voltages on gyros #1, #2,and #3 from the 10 volt level used for spin axis alignment to 200millivolts (0.2 volts), which is the level that will be used for datacollection throughout the Science Phase of the mission. We use highervoltage in the GSS whenever we are controlling the position of thegyro rotors. However, during the data collection phase, we use thelowest voltage required to maintain proper suspension, so that onlythe effects of relativity will be influencing the spin axis deflections ofthe gyros.After lowering the suspension voltages, we used ultraviolet light,shining through fiber optic cables as we have done previously, toremove any excess electrical charge that has built up on the rotors.When ultraviolet light shines on certain metals, it liberates electrons.Two fiber optic cables are embedded in each gyro housing—one ateach end—and each fiber optic cable terminates at an electrode,located just above the rotor surface, When the ultraviolet lamps areturned on, electrons form between the electrode and the rotor surface,and by changing the bias on these electrodes, we can control thedirection of electron flow, either towards or away from the surfaces ofthe rotors.Finally, this morning, we commanded the spacecraft into back-updrag-free mode, balanced around gyro #3. After testing the spacecraftin both primary and back-up drag-free modes over the past few weeks,we have determined that back-up drag-free mode has yielded the mostreliable and efficient performance, and thus, the spacecraft will remainin this mode for the duration of the Science Phase. We will continuetuning the drag-free performance of the Attitude and TranslationControl (ATC) system in the early portion of the Science Phase tocorrect for a previously reported, unknown force, which is causingexcess helium flow from the dewar through the micro thrusters. Thecurrent science configuration of the spacecraft has very little marginfor increased helium flow.In next week’s highlights, we will look back over the IOC period andput it into the perspective of the whole mission. In the process of doingthis, we will hopefully answer a number of email inquiries we havereceived recently regarding the health, longevity, and success of theGP-B mission.3 SEPTEMBER 2004—GRAVITY PROBE B MISSIONUPDATE: DAY 136As of Day #136, GP-B has successfully completed its first full week inthe Science Phase of the mission, with gyros #1, #2, and #3 in sciencemode. Gyro #4 is still undergoing alignment of its spin axis, which weexpect to be completed in about a week. For the past week, thespacecraft has been in drag-free mode around gyro #3.The spacecraft remains in excellent health, rolling at a rate of 0.7742rpm, with all subsystems performing well. The telescope continuesproperly tracking the guide star, IM Pegasi, during the portion of eachorbit when the guide star is visible. We are still investigating a smallforce or bias along the roll axis of the spacecraft, but this bias has noeffect on science data collection. Moreover, during the past two weeks,we have tuned the spacecraft’s Attitude and Translation Control(ATC) system to compensate for this bias, with no excess expenditureof helium through the micro thrusters.Having just achieved the major milestone of transitioning into theScience Phase of the mission, this is a good time to pause and lookback over the Initialization and Orbit Checkout (IOC) phase of themission. During this 19-week period, the GP-B mission has alreadyachieved a number of extraordinary accomplishments:• The orbit injection of the spacecraft was so close to perfect (within6 meters of the target orbit plane) that none of the planned orbittrim operations were necessary.• We’ve communicated with the spacecraft over 3,000 times duringthe IOC phase, and the Mission Planning team has successfullytransmitted over 70,000 commands to the spacecraft without anerror.• GP-B is the first satellite ever to achieve both 3-axis attitude control(pitch, yaw, and roll), and 3-axis drag-free control. Essentially,while orbiting the Earth, the whole spacecraft flies around one ofthe science gyros.• The GP-B gyros, which are performing perfectly in orbit, will belisted in the forthcoming edition of the Guinness Book of WorldRecords as being the roundest objects ever manufactured.484 March 2007 Appendix C — Weekly Chronicle of the GP-B Mission
• The spin-down rates of all four gyros are considerably better thanexpected. GP-B’s conservative requirement was a characteristicspin-down period (time required to slow down to ~37% of its initialspeed) of 2,300 years. Recent measurements show that the actualcharacteristic spin-down period of the GP-B gyros exceeds 10,000years—well beyond the requirement.• Once tuned up, the spacecraft’s Attitude and Translation Control(ATC) system has been able to function at a spacecraft roll rate of0.7742 rpm—more than twice the roll rate of 0.3 rpm initiallyspecified.• The magnetic field surrounding the gyros and SQUIDs (SuperconductingQUantum Interference Device) has been reduced to0.0000001 gauss, less than one millionth of the Earth’s magneticfield—the lowest ever achieved in space.• The gyro readout measurements from the SQUID magnetometershave unprecedented precision, detecting fields to 0.0000000000001gauss, less than one trillionth of the strength of Earth’s magneticfield.• The science telescope on board the spacecraft is tracking the guidestar, IM Pegasi (HR 8703), to superb accuracy, and it is alsocollecting long-term brightness data on that star.A number of people have asked the following two-part question aboutGP-B: “Given that our gyros are spinning about half as fast as weoriginally anticipated, and that the IOC phase took about twice as longas originally anticipated, how will these two situations affect thesuccess of the GP-B experiment?”Regarding the gyros, several of the accomplishments above—especially the extremely low SQUID noise and higher than plannedspacecraft roll rate—have effectively reduced the error factor in theGP-B science experiment, thereby partially compensating for thereduced spin rates of the gyros.Regarding the extended length of the IOC phase, the GP-B mission isunique because it is truly a physics experiment in space. As such, thereare trade-offs that can be made. The primary trade-off we had towrestle with was: More optimization/calibration of the instrumentprior to entering science, with a shorter data collection period; or, lessoptimization/calibration, with a longer data collection period. Weconcluded that the best overall accuracy would be achieved byensuring that the science instrument was optimally calibrated from thestart, even if this meant collecting data for a shorter period than wehad hoped. And, in fact, we now have a considerably betterunderstanding of the instrument than originally anticipated at thisstage of the mission.The original ideal duration of the experiment was 13 months ofrelativity data gathering, but this is not essential, especially in view ofthe work we have now done on the optimization/calibration phase.After two months of science data collection, we can make a very goodmeasurement of the geodetic effect and a significant measurement ofthe frame-dragging effect. The data improves as the 3/2 power of thetime (i.e. double the time, and the result will improve by a factor of~3). In the near future, we will make another measurement of theresidual helium in the dewar, which will provide an accuratedetermination of its cryogenic lifetime. This, in combination with theobserved instrument performance, will indicate the final expectedaccuracy of the experiment.The GP-B program will not release the scientific results obtainedduring the mission until after the science phase has concluded. It iscritically important to thoroughly analyze the data to ensure itsaccuracy and integrity prior to releasing the results. After more than40 years of development, we have learned the value of thoroughnessand patience.10 SEPTEMBER 2004—GRAVITY PROBE B MISSIONUPDATE: Day 143Just over 20 weeks in orbit, GP-B remains in the Science Phase of themission. Gyros #1, #2, and #3 are in science mode, generatingrelativity data. Alignment of the spin axis of gyro #4 with the guidestar, IM Pegasi, is continuing and will be completed by early nextweek.The spacecraft remains in excellent health, rolling at a rate of 0.7742rpm (one revolution every 77.5 seconds). The Attitude andTranslation Control (ATC) system is maintaining a drag-free orbitaround gyro #3, and it is properly tracking the guide star, IM Pegasi,during the portion of each orbit when the guide star is visible. Thedewar temperature is nominal, and the flow of helium, venting fromthe dewar through the micro thrusters to maintain the drag-free orbithas remained within expected limits. All other spacecraft subsystemsare continuing to perform well.On Tuesday, September 7, a double-bit error occurred in a non-criticalmemory location of the spacecraft’s main (A-side) computer due to aproton hit. This type of error is likely to occur from time to timeduring the mission. The necessary correction was prepared anduploaded to the proper memory location of the computer. Thisincident had no effect on science data collection or spacecraftsubsystems.Our statement in last week’s highlights that the GP-B program will notbe releasing any scientific data or results until after the completion ofthe science and instrument re-calibration phases of the missionprompted several inquiries that essentially boil down to two questions:1) What steps have we taken to ensure the integrity of the raw data andthe accuracy of the results? And, 2) Why is it necessary to wait so longbefore releasing any results?GP-B’s principal investigator, Professor Francis Everitt, has beenquoted on several occasions as saying: “I don't care whether Einsteinwas right or wrong; what I want is the experimental truth.” This is ourguiding philosophy here at GP-B. The results of the GP-B experimentwill be invaluable to science whether or not they agree with Einstein'spredictions. Also, given that this experiment is unlikely to ever berepeated, everyone on the GP-B team feels a great sense of personalresponsibility to be as careful and thorough as possible in collectingthe data and cross checking our instruments and procedures foraccuracyMore specifically, in answer to the first question above, manysafeguards are built into the GP-B experiment to ensure the integrityof the raw data, the correctness of the data analysis, and the accuracyof the results. These safeguards include:• GP-B is a joint effort between NASA, Stanford, and LockheedMartin. People from NASA and Lockheed Martin work on site herein the GP-B facilities at Stanford, and NASA managers review allGP-B mission activities.• GP-B has an external Science Advisory Committee, comprised ofrenowned physicists and space scientists. That committee hasoverseen the preparations for data collection, and it will review allof the data and analysis before the results are published.Gravity Probe B — Post Flight Analysis • Final Report March 2007 485
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Post Flight Analysis — Final Repo
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Signatures & ApprovalsPrepared byPu
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Table of ContentsPreface . . . . .
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6.8 Sources and References . . . .
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11 Telescope Readout Subsystem (TRE
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14 Data Collection, Processing & An
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xiv March 2007 Table of Contents
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Figure 3-4. The GP-B dewar—one of
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Figure 8-5. The Seasons of GP-B . .
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Figure 11-20. Pointing angle differ
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Figure 14-9. In the Anomaly Room, t
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xxiv March 2007
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Table 13-3. GP-B payload magnetomet
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xxviiiMarch 2007
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2 March 2007 Chapter 1 — Executiv
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facility, it was necessary to recas
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spacetime around with them as they
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After years of work and the inventi
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axis of a gyroscope rotor changes i
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Figure 1-8. Clockwise, from top lef
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“management experiment.” This w
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Attitude-Control Gyroscopes. Two pa
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Any significant deviation from “g
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established, ranging from Level 1 (
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1.14 The Broader Legacy of GP-BAt l
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24 March 2007 Chapter 2 — Overvie
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Figure 2-1. GP-B Historical Time Li
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Applied Physics Laboratory, of the
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William Fairbank once remarked: “
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In Einstein’s view, space and tim
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y a mere 1.1 inches. You can see th
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Figure 2-10. Schematic diagram of t
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Figure 2-12. Final assembly of the
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Sun Shield. The sun shield is a lon
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2.1.8 The Broader Legacy of GP-BWhe
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2.3 Spacecraft SeparationThe Solar
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Flight Anomalies.) Furthermore, a d
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Table 2-2. Weekly summary of IOC ac
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2.4.3.2 Guide Star AcquisitionAbout
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A second mass trim operation had be
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On Friday, 2 July 2004, the spin ra
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Low temperature bakeout was first p
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2.5.1.3 Lockheed Martin Team Phase-
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Monthly Highlights of the GP-B Scie
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2.6.1 Overview of the Calibration P
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Weekly Highlights of the GP-B Final
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66 March 2007 Chapter 3 — Accompl
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It was in this pristine, near-zero
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Each quartz rotor is coated with a
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Figure 3-3. Functional diagram of a
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Based on data from the on-board tel
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Ideally, the telescope should have
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Figure 3-9. Schematic diagram of st
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used. The star trackers are essenti
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Result: By using the porous plug, w
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Solution: Create a tetrahedral lapp
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Constraint 2: The exhaust tube must
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Result: The on-orbit gyroscope spin
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spacecraft's subsystems for the dur
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Constraint 3: Keep the spacecraft p
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Technology Category Specific Implem
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96 March 2007 Chapter 4 — GP-B On
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Any significant deviation from “g
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packages, one for each Ping load an
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In addition to these software packa
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Table 4-6. Features & benefits of W
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This software added considerable ef
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It is said that “an experiment is
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Table 4-10. Significant Events/Sour
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Figure 4-5. Pictorial depiction of
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Figure 4-7. Eta-Average Error Assoc
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4.4.4.2 OD Using SLR DataFigure 4-9
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4.4.5 ConclusionsFigure 4-11. Compa
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Overall, the storage issues did not
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Table 4-11. ITF equipment listEQUIP
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124 March 2007 Chapter 5 — Managi
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5.2 Overview of GP-B Anomalies in O
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Figure 5-1. Anomaly Review Team Org
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5.3.3.1 Anomaly Investigation and R
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5.3.5 Anomaly Identification and Re
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5.4.3 Risk Management ApproachThe r
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Table 5-1. Summary of Open GP-B ris
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138 March 2007 Chapter 5 — Managi
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140 March 2007 Chapter 6 — The GP
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3. Payload Integration, Testing and
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Figure 6-1. Clockwise from top left
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MSFC conducted an in-house Phase A
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It is important to note that from t
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6.3.1 Incremental PrototypingThe pe
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alignment, and act as an accelerome
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Figure 6-9. The Lockheed Martin GP-
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Furthermore, a fourth electronic sy
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positive thermal connections betwee
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astrophysics/cosmology. Many of the
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Figure 6-10. MSFC Program Managers/
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As described in Chapter 2, the flig
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6.7 Some Observations on the Manage
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168 March 2007 Chapter 6 — The GP
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170 March 2007 Chapter 7 — Attitu
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7.1.2 Vehicle ATC ModesThere are es
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The output of the pressure transduc
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Figure 7-3. Science Telescope Compo
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Figure 7-5. Pitch and Yaw Pointing
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Figure 7-7. Magnitude of the roll r
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Changing the method by which the gy
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7.3.3 Drag-Free Control SystemFigur
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7.3.3.1 DFS - PerformanceThe GP-B d
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Figure 7-15. Mass flow effects of a
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7.5.2 Successful recovery from mult
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If the vehicle control system were
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accomplish this, the ARPs are mount
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7.5.6.1 South Atlantic AnomalyProto
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Figure 7-23. Effects on telescope p
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200 March 2007 Chapter 7 — Attitu
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202 March 2007 Chapter 8 — Other
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Figure 8-2. Block Diagram of CDH co
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8.1.1.4 WATCH DOG TIMERFigure 8-4.
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of eclipses each day (approximately
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Figure 8-8. GSS1 Temperature Trends
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Figure 8-10. Forward Dewar Vacuum S
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The Gravity Probe B spacecraft has
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Figure 8-13. Forward -X Thruster Te
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gaFigure 8-15. Aft -X Thruster Temp
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Because there are only two SQUID br
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Because the specifications for SRE
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8.3.2 Critical Mission RequirementT
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Figure 8-19 is a plot of the power
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Battery Performance Summary:Figure
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Figure 8-23. Solar Array Temperatur
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8.3.10 ConclusionThe electrical pow
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8.4.1 TDRSS OperationsFigure 8-28.
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Figure 8-30. Xpndr-A STDN (green),
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Figure 8-32. Plot of TDRS AGC vs Te
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The FSW also met its subsystem leve
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Appendix E, Flight Software Applica
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Table 8-4. SCRs Addressed in On-orb
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The software and macro changes resu
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Figure 8-38 below is an excerpt fro
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Figure 8-40. A-side CCCA Single Bit
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Figure 8-43. A-side CCCA Single Bit
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When single MBEs did not result in
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256 March 2007 Chapter 9 — Gyro S
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9.1 GSS Hardware DescriptionFigure
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significantly reduces and thus pres
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9.1.11 Clock synchronizationThe aft
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Figure 9-8. Block diagram of the LQ
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direction (transverse to the space
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9.2.2.2 Spin-up SuspensionDuring sp
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Figure 9-16. Predicted and measured
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Figure 9-18. The GSS passes rotor c
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Figure 9-20. Representative drag-fr
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Table 9-1. GSS Science Mission Mode
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Table 9-3. GSW application source l
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The Design and Testing of the Gravi
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282 March 2007 Chapter 10 — SQUID
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ate uncertainty). Although we have
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All of the GP-B electronics have be
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10.3 Pre-Launch Ground-Based TestsW
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Figure 10-6. AC Magnetic Shielding
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Figure 10-8. Temperature Error of S
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Figure 10-10. Quiescent SQUID Noise
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Analog control loops on the electro
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The science support applications ru
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Table 10-7. SSW application source
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308 March 2007 Chapter 11 — Teles
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Figure 11-1. Block diagram of TRE a
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Additionally, the warm electronics
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Figure 11-3. CLL switch states duri
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Table 11-3. Dates and UTC times whe
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Figure 11-7. Low Gamma Angle Data S
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s N+w i= sign+w i++−+−w i−w i
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expression, which otherwise on a po
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Figure 11-14. Y axis, B side RMS po
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Figure 11-17. X axis, B side curren
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Figure 11-20. Pointing angle differ
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Figure 11-24. Scaled summed current
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Figure 11-26 through Figure 11-29 s
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334 March 2007 Chapter 12 — Cryog
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12.2 Temperature / pressure control
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control the space vehicle without t
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Figure 12-3. Helium flow rate predi
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helium at 1.8 K. It does not appear
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Figure 12-6. Flow meter and ATC flo
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were generally within a day or so o
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shields) and subsequent instability
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350 March 2007 Chapter 12 — Cryog
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352 March 2007 Chapter 13 — Other
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Figure 13-2. ECU-operated heaters i
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13.1.3.1 Vatterfly Valve Operations
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13.1.3.7 Payload MagnetometersThe E
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Figure 13-11. ECU performance durin
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As we entered the second month of o
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During the last month of IOC, prepa
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Figure 13-19. ECU heater activity d
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Table 13-1. Proton monitor channel
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Figure 13-21. Proton Monitor data i
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In November, 2004 there was a large
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Figure 13-28 shows a correlation th
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13.3.1 About the MagnetometersFigur
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13.3.2 Other Applications for Paylo
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Figure 13-35. GPS Antennae Field of
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Figure 13-37. Master Antenna Switch
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Figure 13-39. Time difference betwe
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13.4.6 On-Orbit ResultsThe GPS comp
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and velocity values erroneously cal
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E. G. Lightsey, C. E. Cohen, B. W.
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Figure 13-45. A Bottom View of the
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Figure 13-48. The GMA configuration
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Table 13-10. Summary for Helium Gas
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398 March 2007 Chapter 14 — Data
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a relatively slow data rate, so we
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Figure 14-4. NASA ground stations a
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electronic components to recover fr
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By a process of elimination, the GP
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A special room in the GP-B Mission
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Starting on 3 December 1725, Bradle
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seemed that aberration of starlight
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14.1.6 Telescope Dither—Correlati
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14.1.6.3 The Telescope Dither Patte
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amplifications. Thus, in addition t
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14.2.2 Independent Data Analysis Te
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monthly time scales. Though only sh
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424 March 2007 Chapter 15 — Preli
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Figure 15-2. A diagram of the GP-B
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15.4 The Two Surprises and Their Im
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Near Zeroes.) The exception that we
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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
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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 480 and 481: Figure 16-1. Six interacting transl
Page 482 and 483: 16.1.3.2 Training and certification
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 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
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Page 558 and 559: DateSeverity40 11-May-04 Obs T Dwel
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DateSeverity68 16-Jun-04 Medium Dec
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DateSeverity84 13-Jul-04 Obs F Slig
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DateSeveritySubtypeTitle Descriptio
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DateSeverity116 26-Sep-04 Obs F SG3
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DateSeverity132 20-Dec-04 Obs F Unc
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DateSeverity149 5-Mar-05 Obs T Few
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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 584 and 585:
Page 586 and 587:
Page 588 and 589:
ReqIDLevel 1CSCSRM Solid StateRecor
Page 590 and 591:
Page 592 and 593:
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
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