Спутник ФКИ. Gravity Probe B. [Редактировать]

Gravity Probe B (GP-B) — американская космическая миссия по измерению чрезвычайно слабых эффектов геодезической прецессии гироскопов на орбите вокруг Земли и увлечения инерциальных систем отсчёта вращением Земли, которые предсказывает общая теория относительности Эйнштейна. Разработкой дьюара, контейнера научной аппаратуры и электронного оборудования для GP-B занимался отдел новых технологий компании «Lockheed Martin». Для изготовления самого космического аппарата Стенфордским университетом была выбрана компания «Lockheed Martin Missiles & Space», Саннивейл.
Спутник был запущен 20 апреля 2004 года, сбор данных начат в августе 2004. На орбите спутник отработал в целом 17 месяцев и завершил свою миссию 3 октября 2005 года. Обработка полученных данных велась до мая 2011 года и подтвердила существование и величину эффектов геодезической прецессии и увлечения инерциальных систем отсчёта, хотя и с точностью, несколько меньшей изначально предполагавшейся.
Спутник Gravity Probe B нёс на борту самые точные на тот день гироскопы в мире. Точность измерений положения оси позволяет обнаружить два эффекта, предсказываемые общей теорией относительности:

  • геодезическую прецессию, возникающую вследствие искривления пространства-времени.
  • прецессию за счёт увлечения инерциальной системы координат вблизи вращающегося массивного тела (Земли).

Геодезическая прецессия возникает из-за искривления пространства-времени Землёй. В искривленном пространстве, если обнести вектор по замкнутому контуру, он не возвратится в исходное положение, а изменит направление на некоторый угол (см. параллельное перенесение). В данном случае роль вектора выполняет спин гироскопа, а орбита спутника выступает в качестве замкнутого контура. Для параметров GP-B, по расчётам, суммарный угол отклонения должен равняться 6,6 угловых секунд в год. Отклонение спина должно наблюдаться в плоскости орбиты спутника.
Прецессия второго типа на два порядка слабее и возникает из-за увлечения пространства вращением Земли. Если поместить горизотнально вращающийся гироскоп на полюсе Земли, он начнёт очень медленную прецессию в направлении вращения Земли (против часовой стрелки на северном полюсе). Интересно, что на экваторе должна наблюдаться обратная картина: пространство ближе к Земле увлекается больше, и прецессия должна происходить в другую сторону, по часовой стрелке, если смотреть со стороны северного полюса. Для GP-B прецессия из-за увлечения инерциальной системы отсчёта должна составить примерно 0,014 угловых секунд в год.
Идея эксперимента достаточно проста. Система из четырёх гироскопов жёстко закрепляется на главный телескоп спутника, телескоп наводится на ведущую звезду и поддерживается в строго фиксированном направлении в течение всего полёта. Вначале гироскопы раскручиваются так, чтобы их оси совпадали с осью главного телескопа. После этого микроскопическое смещение осей можно будет измерить с помощью SQUID (сверхпроводящее квантовое интерференционное устройство). Измеренное таким образом смещение осей гироскопов будет только за счёт ожидаемых эффектов — геодезической прецессии и увлечения инерциальной системы координат.
Спутник движется по свободной от сноса орбите. Это означает, что орбита спутника постоянно (с частотой 10 раз в секунду) корректируется по движению центра масс одного из гироскопов, который, как и три остальных, защищён от всех внешних воздействий (атмосфера, магнитное поле Земли, давление солнечного света и т. д.), кроме взаимодействия с гравитационным полем. Координаты спутника регистрируются с помощью системы GPS. Гироскопы вращаются с угловой скоростью около 4000 оборотов в минуту. Они подвешены электростатически на расстоянии долей миллиметра от стенок полости. Чтобы избежать контакта гироскопа со стенками, позиция полости относительно гироскопа корректируется 220 раз в секунду.
Роторы гироскопов GP-B изготовлены настолько совершенными, что можно исключить из рассмотрения вероятность прецессии из-за механических дефектов или электрических сил. Прибор способен зафиксировать смещение осей вплоть до 0,5 миллисекунд угловой дуги в год. Для сравнения, этот угол будет примерно равен углу, под которым виден человеческий волос с расстояния 32 км. Согласно ньютоновской механике, совершенный сферический гироскоп в отсутствие внешних сил не испытывает прецессии, то есть если вначале его ось была направлена на определённую звезду, она будет оставаться в таком положении всегда. В 1960 году доктор Леонард Шифф из Стенфордского университета на основании уравнений Эйнштейна и уравнений движения частицы со спином, выведенных Папапетру (уравнения Папапетру-Диксона (англ.)), вычислил величину прецессии осей гироскопов и предложил произвести эксперимент, либо в лаборатории на Земле, либо в космосе. Из его расчётов следовало, что эффект в лаборатории будет на несколько порядков меньше, поэтому орбитальный эксперимент более предпочтителен.
Основная научная аппаратура спутника:

  • Основные приборы — корпус гироскопа, телескоп и несущие конструкции — изготовлены из кварцевого стекла. Кварц практически не подвержен тепловому расширению в широком диапазоне температур — расширяется и сжимается очень мало и очень однородно. Кварцевые детали были изготовлены компанией Speedring из города Куллман, штат Алабама.
  • Главный телескоп имеет апертуру 14 см и направлен на двойную звезду IM Пегаса (HR 8703).
  • Техники центра Маршалла (Marshall Space Flight Center) создали совершенное полировочное оборудование, позволившее им выточить самые сферические объекты из когда-либо изготовленных человеком — роторы гироскопов спутника. Шероховатость поверхности сфер составляет всего несколько десятков атомных слоёв — если увеличить их до размера Земли, самая высокая гора или самая глубокая впадина будет всего 2,4 метра в высоту.
  • Инженеры в Стенфорде разработали технологию нанесения тонкой (всего несколько нанометров в толщину) сверхпроводящей ниобиевой плёнки на поверхность сферы.
  • Основное измерительное оборудование GP-B помещено в сигарообразную 2,7-метровую криогенную ёмкость, окружённую слоем сверхпроводящей свинцовой фольги для защиты от внешних магнитных полей. Эта ёмкость, в свою очередь, вместе со сверхпроводящей оболочкой, помещена в сосуд Дьюара, в момент запуска содержавший 2441 л жидкого гелия. Для поддержания ниобиевой плёнки в сверхпроводящем состоянии необходимо поддерживать криогенную температуру 1,8 К.
  • Направление оси вращения гироскопа детектируется по магнитному моменту (Лондоновскому моменту), который генерирует вращающийся сверхпроводник. Детекторами поля служат квантовые интерферометры (СКВИДы) с чувствительностью, позволяющей измерять магнитное поле на 10 порядков более слабое, чем поле Земли.
  • Сверхтекучий гелий в сосуде Дьюара спутника служит не только для поддержки криогенной среды, но и как рабочее тело реактивных микродвигателей для манёвров при точной наводке телескопа.
  • Более 400 электрических проводов, а также звёздный свет, который попадает в криогенную среду, нагревают сосуд Дьюара. Из-за этого тепла жидкий гелий потихоньку выкипает. Поэтому специалисты Стенфорда изобрели специальную «пористую пробку», которая отводит выкипевший газообразный гелий из сосуда Дьюара, оставляя только жидкий гелий и поддерживая необходимую криогенную температуру.
  • Газообразный гелий пропускается через несколько внешних охлаждающих слоёв сосуда Дьюара, а затем выбрасывается в космос одним из восьми микродвигателей на борту спутника. На основании данных телескопа и положения гироскопов, выходящий гелий аккуратно дозируется таким образом, чтобы поддерживать один из четырёх гироскопов строго в центре масс всей системы.

Дополнительные наименования

#НаименованияПоиск в новостяхПоиск в документах
128230НайтиНайти
22004-014AНайтиНайти

Дополнительная классификация

#Наименования
1Тип орбиты - НОО
2Страна оператор(владелец) - США
3Страна производитель - США
4Тип оператора(владельца) - государственный

Новостная лента[Найти информацию в новостях] [Найти информацию в документах]

#Новостная лента.
12005-01-21. Получены отказы от быстрых протоновТэги: Gravity Probe B

Технические характеристики

#ХарактеристикаЗначение
1Масса КА, кг3100
2Габариты, метра6.4x6.2
3Мощность, Вт606
4Мощность (платформа), Вт293
5Мощность (полезная нагрузки), Вт313

Характеристики орбиты

#ХарактеристикаЗначение
1Наклонение, градусов90
2Период, минут97.6
3Апоцентр, км645
4Дата окончания работы2010-12-08
5Перицентр, км641

Пусковые характеристики

#ХарактеристикаЗначение
1Космодром База Ванденберг
2Средство выведения 1x*Delta 2 (7920, 7925)
3Дата пуска2004-04-20
4Код NSSDC2004-014A

Экономические характеристики

#ХарактеристикаДата измеренияЗначение
1Разработчик Lockheed Martin
2Прогнозируемая стоимость (разработки), млн. долл.2000-04-01615
3Прогнозируемая стоимость (разработки), млн. долл.2001-04-01631
4Прогнозируемая стоимость (разработки), млн. долл.2002-04-01667
5Прогнозируемая стоимость (разработки), млн. долл.2003-01-01709.3
6Прогнозируемая стоимость (проекта), млн. долл.2003-01-01734.9

Информация об удачном запуске

#ХарактеристикаЗначение
1Дата пуска2004-04-20 at 16:57:26 UTC
2Полезная нагрузка 1xGravity Probe B
3Ракета-носитель 1xДельта 2

Найдено 1000 документов по запросу «Gravity Probe B». [Перейти к поиску]


Дата загрузки: 2017-03-09
Скачать документ
0.05/5
..., as well as various micro-gravity experiments for several academic institutions... surveys: measuring parameters of Earth's gravity field, creating a highly accurate geodetic... Mach 1.2 under the influence of gravity. During the descent phase, the... to the programme. ESA’s GOCE gravity mission achieved another major milestone..., ILA 2010, to extend the Gravity Recovery and Climate Experiment - 23... towards Earth for its final gravity-assist swingby, scheduled for 13... the orbit of Europe's GOCE gravity-measuring - 44 - satellite in a successful... AND ADVANCES VI.1 Propulsion ESA’s gravity mission GOCE released its first... that the gravity measurements taken by GOCE are of true gravity, the... km could potentially drown the gravity data. This posed a technological challenge... success of GOCE´s ultra-sensitive gravity measurements depends on finely controlling... explore the extreme Universe. >> ESA’s gravity mission GOCE issued its first... gravitational potential defined by the gravity field - crucial for deriving accurate... a robot using a tether under a micro-gravity environment. >> VI.7 Space Research Facilities... dedicated to measuring the Earth’s gravity field and modelling the geoid... mission objectives are to determine gravity-field anomalies with an accuracy... 1-2 cm. Data from this advanced gravity mission will improve our knowledge... calculations, validated with gravity observations from the Gravity Recovery and Climate Experiment..., terrain camera, radar sounder), for gravity studies (VLBI and data relay... for launch in 2012. GRAIL (Gravity Recovery and Interior Laboratory) was... is to map the lunar gravity field with unprecedented precision, using... UT on 6 October 2008, gaining a gravity assist that tightened its orbit... combination of electric propulsion and gravity assists, the planned cruise duration... and, along with high precision gravity data, revolutionized studies and understanding... of the nominal mission (including gravity measurements and seasonal coverage), to... Jupiter in early 2008 for a gravity assist and scientific studies (see... variation, albedo, spectrum, mineral composition, gravity, and the main chemical composition.... After a successful commissioning phase, a Mars gravity assist was successfully performed in... that the cratering process was gravity-dominated, lending to the notion... to reach the cometary target, gravity assists (and accompanying science studies... in late 2005. A third Earth-gravity assist occurred in November 2009... study of the magnetic and gravity fields with unprecedented precision, and... in another. Observations of Titan’s gravity field and spin state are... important ingredient in geospace variability. Gravity waves generated by hurricanes or... frequencies and scales, such as gravity waves, tides, and planetary waves... X-ray sky monitoring and survey. gravity waves sub-mm LISA Pathfinder... Biology Here, we focus on gravity perception, genetic and physiological modifications... response to microgravity or simulated gravity. Genetic studies are typically paired...-based low-G simulation; gravity perception and orientation; gravity scale effects; centrifuge high... plants are light and gravity. With regard to gravity, this is quite... increasing evidence, that changes in gravity are sensed as environmental stress... the involvement of phytohormone transport (gravity-induced changes in the localization... effect in early phases of gravity reception, but can optimize statolithreceptor... (e.g. selfsustained oscillations without impact of gravity), gene expression studies prevail, but... further examine specific steps of gravity sensing and signal transduction, genetically... and Cologne in which artificial gravity, exercises and nutritional measures will... usually negligible with respect to gravity, can dominate fluid behaviour and... reported in the following paragraphs. Gravity Probe-B (US with some data analysis... fields of geopotential modelling (Earth’s gravity and magnetic fields), oceanography (altimeter... strongly supporting mission operations and gravity field determination from a complement of... field of precise orbit and gravity field determinations from Lunar and... improved gravity field models for Mars and a better observation of temporal gravity... NASA for more advanced future gravity field satellites, relying on very... (Category III due to a Mars gravity assist) continues on course, using...’s next Discovery-class mission, the Gravity Recovery and Interior Laboratory (GRAIL... 2016. Juno will map the gravity field, magnetic field and atmospheric... (Category II due to Venus gravity assist), is a joint mission between... Explorer (NASA) fiscal year Earth gravity Global Assimilation of Ionospheric Measurements... Plasma Model Geospace Environment Modelling Gravity and Extreme Magnetism SMEX Geostationary... Model Global Navigation Satellite System Gravity field and steady-state Ocean... Spacecraft Gravity Probe B Global Plasmasphere Ionosphere Density Global Positioning System General Relativity Gravity Recovery and Climate Experiment Gravity Recovery and Interior...



Дата загрузки: 2017-03-18
Скачать документ
0.21/5
... gravitational wave Universe Deep Space Gravity Probe Make a key step toward detecting... physical laws of the Universe? Probe gravity theory in the very strong... ionised matter trapped by the gravity of celestial objects. ESA’s tradition... in 1974-1975 with the gravity-assist method, this mission is... unknown dark energy has made gravity push the Universe apart rather... the normally attractive action of gravity. He did not want to... the inward pull of normal gravity. When, a few years later, the... cannot eliminate the effects of gravity except by allowing apparatus to... missions like Gravity Probe-B (GP-B) and the Wilkinson Microwave Anisotropy Probe (WMAP) are making fundamental studies of gravity and the... reveal the existence of extra gravity-like forces. A coldatom mission containing... limits. Does Newton’s law of gravity hold at very small distances... Solar System, Newton’s law of gravity works very well. Small corrections... unified theories, the way that gravity depends on the distance between... short-range forces or because gravity itself changes. Because of LAYOUT3.... Ultra-precise tests of Newton’s gravity using a drag-free satellite in... run. Space experiments could measure gravity down to micron distances, an... today. Does Einstein’s theory of gravity hold at very large distances... usually predict small changes in gravity in the Solar System beyond... sensitivity by a dedicated deep space gravity probe. A drag-free satelite in Earth... modified this picture by describing gravity as the curvature of space... quantum theory to gravity, to create a theory of quantum gravity. It is.... It is as if extreme gravity crushes the individuality out of.... Black holes have the strongest gravity, so the X-ray emission produced... give tests of strong-field gravity such as the existence of... predicted by Einstein’s theory of gravity, like strong bending of the... black holes in terms of gravity, but with the crucial difference... diagnostics of the strength of gravity close to, or even on... stars and effects of strong gravity on the matter being episodically... probe its extraordinary nuclear physics. A large-aperture X-ray observatory, which could probe... an observational understanding of strong gravity is within reach during the... theories Use the stable and gravity-free environment of space to... of Newtonian gravity using a trans-Saturn dragfree mission Deep space gravity probe Observe... BeppoSAX. — the discovery of strong gravity effects around black holes, including... that, in effect, converts gravity into anti-gravity, creating the necessary repulsion... extreme conditions, in terms of gravity, density and temperature, than anything... to probe the relevant timescales. These performances would, for example, probe the... 5.2.3 describes a sample return from a low-gravity environment, in this case a near... which the perturbation by Jupiter’s gravity will set the orbiter on..., contemplated in Section 5.3.1 for testing gravity at very large distances. 5.2.2 The.... Retrieving a sample from a small, low-gravity body and delivering it to... necessarily required for such a low-gravity environment, and the descent requirements... of these, directed to testing gravity at long ranges, appear in.... Add the benefits of ‘low gravity’ and a calm environment in space... at the same rate under gravity, is tested by a set of... spin-gravity coupling could be investigated. Searches for deviations from Newtonian gravity..., the effect of small-distance gravity could be measured to micron... source, in the form of a gravity gradiometer. The essential mission requirement... as to measure the Earth’s gravity field over a wide range of... conditions, or with changes in gravity, should reveal any time-dependence... entanglement. 5.3.1.2 Checking the strength of gravity at long ranges An anomalous... a breakdown of Newton’s law of gravity at large distances and, by... series could be a deep space gravity probe that would aim to achieve... gravitational waves. The deep space gravity probe might be accomplished by solar... matter under extreme conditions of gravity. Table 5.4.3.1: The technologies required for... gravity Later Exploring Solar System gravity for violations of Einsteinian (and Newtonian) gravity... Pioneer-10 with a Deep Space Gravity Probe Later Begin particle physics in... theory of the force of gravity, which has preoccupied many theorists... the past 30 years. If gravity is truly a quantum force, then... System. A custom-designed Deep Space Gravity Probe could investigate whether this anomaly...; does the inversesquare law of gravity fail over large distances? We... to the overwhelming effects of gravity in collapsed objects. Fundamental physics... and Gamma-ray Astrophysics Title: Gravity in the Strong Field Limit... ‘Atom’ Optics (NAO) – For Probing Gravity in Space Proposed by: Philippe... the Elementary Particle Spin to Gravity Proposed by: Claus Lämmerzahl et... Category: Fundamental Physics Title: Exploring Gravity in the Quantum Domain Proposed...: Fundamental Physics Title: Test of Gravity-Matter Coupling and Search for...



Дата загрузки: 2017-03-18
Скачать документ
0/5
... the strong interest in testing gravity at all scales, but considers... of an instrument (GAP for Gravity Advanced Package) on a planetary mission... such a unification (string theory, quantum gravity, extra spatial dimensions) tend to... equivalence principle. The law of gravity may be modified at some... to modify the theory of gravity to account for the observational... development of our understanding of gravity. It is central to general..., whether they are modifications of gravity or include extra long range... basis of metric theories of gravity, which predict a universal gravitational redshift... free fall on quantum objects. Gravity may be tested in the... in the superposition law of gravity and  which measures the amount... the context of scale dependent gravity probes different regions. Doppler tracking... the regime of strong field gravity:   v2/c2  GNM/(Rc2)  1. The... will provide key tests of gravity in the strong regime: LISA... hole horizons. Experimental tests of gravity show good agreement with general... we do not fully understand gravity at very large (galactic or... How well do we know gravity at various scales ? poorly reasonably... Dark energy,IR-modified TeVeS, gravity, f(R) gravity, STVG branes,strings and extra... Cosmology Techniques available to explore gravity Cosmology missions clocks, Ongoing space... clocks, time links, accelerometers Table 1: Gravity at all length scales (adapted... tests of the laws of gravity and the search for deviations... of the gravitational interaction (if gravity is indeed quantized). The discovery... are setting complementary limits on gravity. Since their discovery in the... local geometry and thus probe strong field gravity. Reflection spectra of the... will clearly test the strong gravity regime in a more focused and... from the known laws of gravity are obtained from the analysis... a spacecraft as a proof mass for gravity tests requires an adequate knowledge... relativity and alternate theories of gravity. Any inconsistencies in the analysis... the light of scale dependent gravity as discussed above. Landers may... many other fields (geodesy, planetary gravity, global positioning, altimetry, telecommunications, etc... constrain a variety of theories of gravity designed as extensions to general... in some models of quantum gravity which attempt to merge Einstein... dependent gravity Depending on the theoretical model used, a scale dependence of gravity... the most complete characterisation of gravity and its variation with distance... gravity to fundamental constants Local Position Invariance II: Coupling of Sun gravity... Shapiro time delay measurement ×9×106 Probe gravity on large scale; possibly combination... constraints) p: Galileo redshift experiment (1990) q: Gravity Probe-A r: from limits to annual variation... effect), a known loophole of quantum gravity and the Coleman-Glashow effect... fundamental limit imposed by terrestrial gravity gradient noise. The frequency decades... way. Measures to compensate for gravity with additional forces unavoidably perturb... and cosmological observations)  How does gravity behave in the strong field... into the possible unification of gravity and the quantum theory (Standard... matter, which are subjected to gravity and can be seen as... coherently split to propagate through gravity over several classical trajectories. Ground... also be used in reduced-gravity environments, such as drop towers... fall in the Earth’s local gravity field, as long as they... above the importance of testing gravity at all distance scales. Dedicated... efficient study of scale dependent gravity are those required for precise... the most complete mapping of gravity at all attainable scales by... case related to scale dependent gravity is counterbalanced by the complexity... the context of scale dependent gravity, but their chances of selection... time delay and deep space gravity tests with the relative acceleration...), and future possible deep-space gravity tests. Measurement of the relative... frequencies relevant to a deep space gravity test with spacecraft tracking, to... acceleration due to the self-gravity of the spacecraft itself. The..., and will test, spacecraft self-gravity control to the nm/s2... and below is essential for gravity tests using dedicated or planetary... and corresponding constraints (including self-gravity) should be investigated from the... sensitivity for absolute measurement of gravity, gravity gradients and magnetic fields as... atomic clocks, accelerometers, gyroscopes, gravimeters, gravity gradiometers, etc.) is surpassing previous... the  parameter of post-Newtonian gravity theories at the inaccuracy level... the strong interest in testing gravity at all scales, but considers... such as planetary gravitational observations, gravity in our solar system as... Astrometric Interferometer for Astrophysics GAP: Gravity Advanced Package GG: Galileo Galilei... System GOCE: Gravity and Ocean Circulation Explorer GP-A: Gravity Probe A GP-B: Gravity Probe B GPS: Global Positioning System GRACE: Gravity Recovery And...



Дата загрузки: 2017-01-30
Скачать документ
0.08/5
... 9-12 GRAVITY PROBE B Examining Einstein’s Spacetime with Gyroscopes An Educator’s Guide “Gravity Probe B: Investigating... for duplication. Gravity Probe B web site - http://einstein.stanford.edu/ Gravity Probe B email - www... Shannon Range, Kate Stephenson, the Gravity Probe B Image Archives, York University, and...’s Guide to Gravity Probe B * Produced October 2004 by Shannon K’doah Range GRAVITY PROBE B Examining... 3 Table Of Contents Introduction To Gravity Probe B: The Relativity Mission ............. 5 I. Spacetime, Curved...-Dragging and the Role of Gravity Probe B II. “Seeing” Spacetime With Gyroscopes... Small is Small? III. The Gravity Probe B Science Instrument ................................... 22 A. The World... Orbit IV. Concluding Questions Of Gravity Probe B ................................ 33 A. Inertia And Mach’s Principle... Gravity Probe B * Produced October 2004 by Shannon K’doah Range An Introduction To Gravity Probe B Examining the Fundamental Structure of the Universe G ravity Probe B is... twist. GEODETIC EFFECT GRAVITOMAGNETIC EFFECT Gravity Probe B’s objective is to observe and... the greatest precision ever attempted. Gravity Probe B has launched four ultra-spherical... Tuesday, April 20, 2004, the Gravity Probe B spacecraft had a picture-perfect launch... mission. In late August 2004, Gravity Probe B began collecting relativity data from.... 1˚ = 3,600 arcsecs 6 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... ball. In 8 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon...’s relativity. 10 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... Sun. 12 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... be the role of Gravity Probe B? Searching for Gravity Waves A final note about... vibrate when a gravity wave passes by. 14 Educator’s Guide to Gravity Probe B * Produced... & The Role of Gravity Probe B The role of the Gravity Probe B (GP-B) experiment is... satellite Temperature of liquid helium (1.8 K) GRAVITY PROBE B FAST FACTS A near-perfect, spherical... in development A. The Concept of Gravity Probe B A ccording to Einstein’s General Theory... Star. Compared to the Earth, Gravity Probe B’s gyroscope hardly “precesses” at all... Gravity Probe B * Produced October 2004 by Shannon K’doah Range B. The Mechanics of Gravity Probe B The Gravity Probe B mission plan is as follows... to Gravity Probe B * Produced October 2004 by Shannon K’doah Range The Gravity Probe B Science Instrument T o test Einstein’s theory of general relativity, Gravity Probe B must... and 41 milliarcseconds per year), Gravity Probe B needed to build a near-perfect... inch. 24 Educator’s Guide to Gravity Probe B * Gravity Probe B gyroscope (rotor) with quartz housing... SQUID: Reading the Unreadable T he Gravity Probe B gyroscope is nearly perfectly spherical... axis of the magnetic field, Gravity Probe B knows precisely which direction the... magnetic field Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... one readout scheme perfect for Gravity Probe B: extremely sensitive, extremely stable, applicable... x-axis. 28 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon.... D. The Force-Free Environment T he Gravity Probe B science instrument (four gyroscopes in... accuracy of the instrument. For Gravity Probe B to succeed, the instrument must... science instrument could warp. Second, Gravity Probe B depends upon the London moment... with liquid helium. How does Gravity Probe B create a supercooled environment, and keep... maintain its supercooled environment of 1.8 K, Gravity Probe B designed a special dewar (or “Thermos... accurate. 30 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... the helium lasts longer. The Gravity Probe B dewar will create a supercooled environment... to Gravity Probe B * Produced October 2004 by Shannon K’doah Range Concluding Questions Gravity Probe.... 1) Will Gravity Probe B prove or disprove Einstein? Will the results of Gravity Probe B verify... the motion of matter. 2) Will Gravity Probe B prove or disprove “Mach’s Principle... Thomas Vargish, 1987. ARTICLES “The Gravity Probe”. Gary Taubes, Discover Magazine, March... 1972. 34 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... to Gravity Probe B * Produced October 2004 by Shannon K’doah Range (“Seeing” Newton’s Gravity... Gravity Probe B * Produced October 2004 by Shannon K’doah Range The Speed of Gravity... itself. 42 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... pipe. 44 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... mass. 48 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... other. 50 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... central component to the Gravity Probe B experiment. The entire probe and satellite are... Association.) 52 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon...



Дата загрузки: 2017-02-23
Скачать документ
0.03/5
...°C) daily and has only weak gravity. Researchers believed that the asteroid..., “Spacecraft Lands on Asteroid; NASA Probe’s Historic First May Yield Wealth... of a program focused on designing a probe that could collide with a comet...’s theory of microlensing that the gravity of a celestial body can bend... 30 June The Microwave Anisotropy Probe (MAP) launched aboard a Delta 2 rocket... star was that the star’s gravity had pulled the water vapor... first landing of an American probe on another planet, inaugurated a series... use of a microgravity or low-gravity environment to examine the fundamental... also planned 123 Warren E. Leary, “Probe Sends Postcards from Comet’s Core... distant background objects, while the gravity of galaxy clusters in the... it. Because the black hole’s gravity is sufficiently intense to wrap... surrounding the black hole. Observed gravity-stretching particles of light in... was too high for only gravity and the descent of matter... warping of electromagnetic radiation by gravity. The measurement of the redshift...’s largest known structures bounded by gravity―called galaxy clusters―might be... Awaits Last Photographs from Jupiter Probe’s Long Trip,” Houston Chronicle, 16... March Two spacecraft comprising the Gravity Recovery and Climate Experiment (GRACE... to map variations in Earth’s gravity field, using the GPS and... mission, to study measurements of gravity variations, could help scientists understand... E. Leary, “New Satellites To Map Gravity More Precisely,” New York Times... of Large Change in Earth’s Gravity Field,” news release 02-147... a spacecraft maintains a balance between the gravity of the Sun and of... were able to estimate its gravity, compositional material, and other characteristics... of the black hole’s immense gravity on that star. The scientists... with dark matter, Abell 1689’s gravity behaves as a 2 million light-year... of Albert Einstein’s prediction that gravity warps space and therefore distorts... (59-kilogram), University Explorer Class probe, the Cosmic Hot Interstellar Plasma... 2001.433 9 May The Japanese probe Muses-C―renamed Hayabusa (Falcon) after..., aboard an M-5 solidfuel rocket. The probe’s mission was to rendezvous with... first scientific product of the Gravity Recovery and Climate Experiment (GRACE... map to date of Earth’s gravity field, using preliminary data collected..., “Oceanographers Catch First Wave of Gravity Mission’s Success,” news release 03... 23 December 2008); Larry O’Hanlon, “Gravity Map Shows Earth Is Very..., “NASA Outlines Cost of Columbia Probe,” Washington Times, 1 August 2003. 492..., “Senators Rip NASA over Columbia Probe,” 4 September 2003; Brian Berger, “Lawmakers... Recer for Associated Press, “Shuttle Probe Rips White House, Congress,” Washington... 1982 aboard a Centaur rocket. The probe had made significant contributions to... this occurred, the nearer star’s gravity caused the light of the... 20 April NASA launched its Gravity Probe B (GP-B) on a Boeing Delta 2 rocket... move towards them, they create gravity. Einstein’s theory of relativity also... objects spin on their axes. Gravity Probe A, which NASA had launched in..., 21 April 2004; NASA, “The Gravity Probe B: The Relativity Mission,” http://www... dark energy might have counteracted gravity, causing the expansion. Chandra’s observations... moons―the project included the probe Huygens, created to examine Saturn... sand and rock bound by gravity, Whipple had theorized that comets... had examined data from the Gravity Recovery and Climate Experiment (GRACE... 2004. 683 NASA, “NASA’s GRACE Gravity Mission Weighs In on Earth... as Earthoccurs because the gravity of those objects pulls space... orbiter successfully released ESA’s Huygens probe on a controlled course to Saturn... its moons, scheduling the Huygens probe―specifically designed to analyze Titan... ESA announced that its Huygens probe, which had undertaken a seven-year... had selected Titan as the probe’s destination because Titan’s nitrogen atmosphere... and Astronautics: A Chronology, 2001-2005 probe had found several fundamental errors... announced results of the Cassini probe’s first radio occultation observations of... scientific theories, a black hole’s immense gravity is able to pull millions... expect if the black hole’s gravity had drawn the stars toward... clouds. The gravity of the clouds counteracts the gravity of the black.... The spacecraft was ESA’s second probe designed to orbit a specific planet..., “European Space Agency Launches Venus Probe,” 9 November 2005. 857 NASA, “International... Nishiyama for Reuters, “Update 1–Japan Probe Lands and Collects Samples on... the spacecraft’s thrusters had prevented a probe containing samples from launching during... they were uncertain whether Hayabusa’s probe had actually collected samples from... Two Years Before Starting Space Probe’s Return,” Washington Post, 15 December... 7 July 2004) General Circulation Model Gravity Probe B Goddard Institute for Space Studies... Mean Time Global Positioning System Gravity Recovery and Climate Experiment gamma... MSFC MT MRO Microwave Anisotropy Probe Mars Advanced Radar for Subsurface...



Дата загрузки: 2017-01-30
Скачать документ
0.15/5
... performed. ITAR Control required: ii Gravity Probe B Science Results—NASA Final Report... Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Chapter 1 Everitt et al. Gravity Probe B Data Analysis—Status and Potential... Chapter 4 Heifetz et al. The Gravity Probe B Data Analysis Filtering Approach Chapter... Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67 Contents iii iv Gravity Probe B Science Results—NASA Final Report... December 2008 2 Gravity Probe B Science Results—NASA Final Report, December 2008 1 Gravity Probe B Data... al. 3 4 Gravity Probe B Science Results—NASA Final Report, December 2008 Gravity Probe B Data Analysis... details of progress on the Gravity Probe B (GP-B) Relativity Mission. GP-B, launched... analysis approach. 1 The NASA-Stanford Gravity Probe B Mission (GP-B) In 1960, L. I. Schiff... a spinning spherical body. Conceptually, therefore, Gravity Probe B is simple. All it needs... calculate the two predicted effects 6 Gravity Probe B Science Results—NASA Final Report... 2 Quartz Block Telescope Figure 2. The Gravity Probe B Instrument. The heart of the... in a spherical quartz housing. Figure 4. Gravity Probe B gyroscope. A simple argument reveals the... (Muhlfelder, Lockhart et al.(2003)). 8 Gravity Probe B Science Results—NASA Final Report... specific asymptotic values Tpa . 26 Gravity Probe B Science Results—NASA Final Report... problem into a linear one. 28 Gravity Probe B Science Results—NASA Final Report... factor oscillations drops accordingly. 32 Gravity Probe B Science Results—NASA Final Report... and Gyroscope Asymmetry Analysis on Gravity Probe B Using Gyroscope Position Data, Ph...-up Loop Symmetry and Centering, Gravity Probe B document S0243 (Stanford University, Stanford... and Spin Down Rate of Gravity Probe B Gyroscopes, Physics Honor Thesis, Stanford... York, 1995). Salomon M., Properties of Gravity Probe B Gyroscopes Obtained from High Frequency...-B Science Data Analysis 35 36 Gravity Probe B Science Results—NASA Final Report...), Silbergleit et al. (2009)), the Gravity Probe B (GP-B) satellite was designed to... drift rate. 1 Keiser (corresponding author) Gravity Probe B, HEPL, Stanford University, Stanford, CA... 39 2 2.1 Misalignment Torques Observations The Gravity Probe B mission timeline was divided into... Figure 1 shows the measured 40 Gravity Probe B Science Results—NASA Final Report..., M., W. Bencze, et al. (2009). "The Gravity Probe B Data Analysis Filtering Approach", Space... for the GP-B Data Reduction", Gravity Probe B Document S0393, Stanford University, Stanford...." Classical and Quantum Gravity 13: A291-A297. 50 Gravity Probe B Science Results—NASA Final Report, December 2008 4 The Gravity Probe B Data Analysis Filtering Approach Michael Heifetz et al. 51 52 Gravity Probe B Science Results—NASA Final Report, December 2008 The Gravity Probe B Data... Abstract A simple strategy of the Gravity Probe B (GP-B) data analysis has evolved... + noise . ⎩ + [τ EW ( t ) − s EW ( t ) ]sin( Φ r ( t ) + δϕ ) ⎭ 54 Gravity Probe B Science Results—NASA Final Report... analysis. Heifetz et al.: The Gravity Probe B Data Analysis Filtering Approach 55... orbit), full information (inverse 56 Gravity Probe B Science Results—NASA Final Report... -model): Heifetz et al.: The Gravity Probe B Data Analysis Filtering Approach 57... γCg-model (dimensionless values). 58 Gravity Probe B Science Results—NASA Final Report...-seconds). Heifetz et al.: The Gravity Probe B Data Analysis Filtering Approach 59... 6 only). Heifetz et al.: The Gravity Probe B Data Analysis Filtering Approach 61... slope and individual y-intercepts. 62 Gravity Probe B Science Results—NASA Final Report... equivalent. Heifetz et al.: The Gravity Probe B Data Analysis Filtering Approach 63... or a model sensitivity analysis. 64 Gravity Probe B Science Results—NASA Final Report... structure. Heifetz et al.: The Gravity Probe B Data Analysis Filtering Approach 65... data reduction algorithm for the Gravity Probe B Relativity Mission, Ph.D. Thesis, Aero... for the GP-B Data Reduction, Gravity Probe B document S0393 (Stanford University, Stanford... the linearity of the Gravity Probe B Measurement Model, Gravity Probe B document S0632, Rev. C (Stanford... Signal Models and Their Analysis, Gravity Probe B document S0996 (Stanford University, Stanford... Research 32 (7), 1387 (2003). 66 Gravity Probe B Science Results—NASA Final Report...-launch expectation. 1 Muhlfelder (corresponding author) Gravity Probe B, HEPL, Stanford University, Stanford, CA... and resonance torque modeling. 74 Gravity Probe B Science Results—NASA Final Report.... 2× orbital modeled: Blue/Green. 76 Gravity Probe B Science Results—NASA Final Report... estimates, however more work 78 Gravity Probe B Science Results—NASA Final Report..., Chapter 4 of this report). G. M. Keiser, "Gravity Probe B" in Proceedings of the International...



Дата загрузки: 2017-01-30
Скачать документ
0.08/5
... 9-12 GRAVITY PROBE B Examining Einstein’s Spacetime with Gyroscopes An Educator’s Guide “Gravity Probe B: Investigating... for duplication. Gravity Probe B web site - http://einstein.stanford.edu/ Gravity Probe B email - www... Shannon Range, Kate Stephenson, the Gravity Probe B Image Archives, York University, and...’s Guide to Gravity Probe B * Produced October 2004 by Shannon K’doah Range GRAVITY PROBE B Examining... 3 Table Of Contents Introduction To Gravity Probe B: The Relativity Mission ............. 5 I. Spacetime, Curved...-Dragging and the Role of Gravity Probe B II. “Seeing” Spacetime With Gyroscopes... Small is Small? III. The Gravity Probe B Science Instrument ................................... 22 A. The World... Orbit IV. Concluding Questions Of Gravity Probe B ................................ 33 A. Inertia And Mach’s Principle... Gravity Probe B * Produced October 2004 by Shannon K’doah Range An Introduction To Gravity Probe B Examining the Fundamental Structure of the Universe G ravity Probe B is... twist. GEODETIC EFFECT GRAVITOMAGNETIC EFFECT Gravity Probe B’s objective is to observe and... the greatest precision ever attempted. Gravity Probe B has launched four ultra-spherical... Tuesday, April 20, 2004, the Gravity Probe B spacecraft had a picture-perfect launch... mission. In late August 2004, Gravity Probe B began collecting relativity data from.... 1˚ = 3,600 arcsecs 6 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... ball. In 8 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon...’s relativity. 10 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... Sun. 12 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... be the role of Gravity Probe B? Searching for Gravity Waves A final note about... vibrate when a gravity wave passes by. 14 Educator’s Guide to Gravity Probe B * Produced... & The Role of Gravity Probe B The role of the Gravity Probe B (GP-B) experiment is... satellite Temperature of liquid helium (1.8 K) GRAVITY PROBE B FAST FACTS A near-perfect, spherical... in development A. The Concept of Gravity Probe B A ccording to Einstein’s General Theory... Star. Compared to the Earth, Gravity Probe B’s gyroscope hardly “precesses” at all... Gravity Probe B * Produced October 2004 by Shannon K’doah Range B. The Mechanics of Gravity Probe B The Gravity Probe B mission plan is as follows... to Gravity Probe B * Produced October 2004 by Shannon K’doah Range The Gravity Probe B Science Instrument T o test Einstein’s theory of general relativity, Gravity Probe B must... and 41 milliarcseconds per year), Gravity Probe B needed to build a near-perfect... inch. 24 Educator’s Guide to Gravity Probe B * Gravity Probe B gyroscope (rotor) with quartz housing... SQUID: Reading the Unreadable T he Gravity Probe B gyroscope is nearly perfectly spherical... axis of the magnetic field, Gravity Probe B knows precisely which direction the... magnetic field Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... one readout scheme perfect for Gravity Probe B: extremely sensitive, extremely stable, applicable... x-axis. 28 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon.... D. The Force-Free Environment T he Gravity Probe B science instrument (four gyroscopes in... accuracy of the instrument. For Gravity Probe B to succeed, the instrument must... science instrument could warp. Second, Gravity Probe B depends upon the London moment... with liquid helium. How does Gravity Probe B create a supercooled environment, and keep... maintain its supercooled environment of 1.8 K, Gravity Probe B designed a special dewar (or “Thermos... accurate. 30 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... the helium lasts longer. The Gravity Probe B dewar will create a supercooled environment... to Gravity Probe B * Produced October 2004 by Shannon K’doah Range Concluding Questions Gravity Probe.... 1) Will Gravity Probe B prove or disprove Einstein? Will the results of Gravity Probe B verify... the motion of matter. 2) Will Gravity Probe B prove or disprove “Mach’s Principle... Thomas Vargish, 1987. ARTICLES “The Gravity Probe”. Gary Taubes, Discover Magazine, March... 1972. 34 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... to Gravity Probe B * Produced October 2004 by Shannon K’doah Range (“Seeing” Newton’s Gravity... Gravity Probe B * Produced October 2004 by Shannon K’doah Range The Speed of Gravity... itself. 42 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... pipe. 44 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... mass. 48 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... other. 50 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon... central component to the Gravity Probe B experiment. The entire probe and satellite are... Association.) 52 Educator’s Guide to Gravity Probe B * Produced October 2004 by Shannon...



Дата загрузки: 2017-01-30
Скачать документ
0.06/5
...; (Right) Boeing Corporation Launch Companion Gravity Probe B in a Nutshell In 1916, in... theory of Gravity Probe B Launch Companion The experiment aboard the Gravity Probe-B spacecraft is... quantify these minuscule relativistic effects. Gravity Probe-B’s measurement of the geodetic effect... directly been measured before, but Gravity Probe-B is expected to determine its... order to carry out the Gravity Probe B experiment. The spherical gyroscopes have... lifespan, spin offs from the Gravity Probe B program have yielded many technological..., but perhaps most important, the Gravity Probe B program has had a profound effect... Nobel Laureate in Physics. Gravity Probe B Launch Companion Gravity is the most fundamental... way to think about gravity. If the Gravity Probe-B experiment corroborates the two... of matter. Whatever the result, Gravity Probe B will provide us another glimpse... sublime structure of our universe. Gravity Probe B Quick Facts Spacecraft Length 6.43...,077 lbs or 255.5 tons) Gravity Probe B Launch Companion -5 -7 Program Duration 43... dollars 3 4 Gravity Probe B Launch Companion The Space Vehicle All of the Gravity Probe B technologies... specifically for use in the Gravity Probe B mission. Inside the Dewar A Dewar... for holding cryogenic liquids. The Gravity Probe B Dewar will be one of... fills that transforms the liquid Gravity Probe B Launch Companion The quartz block... gyroscopes. 5 The Gravity Probe B Space Vehicle 6 Gravity Probe B Launch Companion The Probe The SIA is... vacuum chamber inside the probe and Dewar. Before Gravity Probe B was completely integrated... electrical lines, that run from Gravity Probe B Launch Companion Sun Shield The... which a satellite is pointing. The Gravity Probe B satellite contains two star trackers... with the guide star. The Gravity Probe B on-board telescope basically performs... star’s position to within a milliarcsecond. Gravity Probe B Launch Companion With such a small... are deployed soon after launch. Gravity Probe B Launch Companion The Space Vehicle... from the Gravity Probe B Mission Operations Center (MOC), located in the Gravity Probe B building... Phase 4. Post-science Calibration Phase. Gravity Probe B Launch Companion Each of these... day of flight operations. The Gravity Probe B space vehicle will lift on... 75 minutes after launch, the Gravity Probe B Space Vehicle will separate from... at this time, if required. Gravity Probe B Launch Companion The nominal timeline... the launch/ early orbit phase. Gravity Probe B — Launch & Early Orbit Nominal Timeline... timeline of the IOC activities. Gravity Probe B — Nominal Timeline of IOC Activities... what forces and torques are Gravity Probe B Launch Companion required to hold... L+22 Days) Spinning up the Gravity Probe B gyroscopes is a delicate and complex...-up and testing sequences, gradually Gravity Probe B Launch Companion The first spin... Einstein’s theory of general relativity, Gravity Probe B must measure two minuscule angles... space. While the concept of Gravity Probe B is relatively simple in design...’s. The GP-B Science Instrument The Gravity Probe B science instrument takes the shape... out the top of the Gravity Probe B satellite. Each gyroscope is suspended... and 40.9 milliarcseconds per year— Gravity Probe B needed to build a near-perfect... from its starting point by Gravity Probe B Launch Companion more than one... from any bearings or supports. Gravity Probe B Launch Companion Alternatively, imagine a GP... supports. 15 Spinning Superconductivity Each Gravity Probe B gyroscope is nearly perfectly spherical... metal. Here was the “marker” Gravity Probe B needed. GP-B scientists coated each... axis of the magnetic field, Gravity Probe B knows precisely which direction the... one readout scheme perfect for Gravity Probe B: extremely sensitive, extremely stable, applicable... the greatest technical challenges for Gravity Probe B is to keep its science...) constantly for at least a year. Gravity Probe B Launch Companion while retaining the... from the Dewar’s inner chamber, Gravity Probe B Launch Companion The porous plug... Department as an offshoot of Gravity Probe B research. Drag-free technology is... the gyroscope signal at the 0.1 Gravity Probe B Launch Companion milliarcsecond level to... quasars separately, so that the Gravity Probe B gyroscope measurements can be related... on-board telescope to track Gravity Probe B Launch Companion IM Pegasi -- HR8703... spin axis drift measurable with Gravity Probe B. Clearly this motion has to... determined with high accuracy for Gravity Probe B to be successful. Because IM...” that obscures it. For the Gravity Probe-B experiments, however, that choice was... the precision of the instruments. Gravity Probe B’s four gyroscopes, housings, and telescopes... is in a near-perfect vacuum, Gravity Probe B Launch Companion surrounded by 645... solid for their entire lifetimes. Gravity Probe B promises to be the near... can find more information about Gravity Probe B: http://einstein.stanford.edu http.../d304/stat us.html Gravity Probe B Launch Companion 21 22 Gravity Probe B Launch Companion



Дата загрузки: 2017-01-30
Скачать документ
0.15/5
...-17, 1982. D. B. DeBra and C. W. F. Everitt, “Gravity Probe B: New Control System Technology in... for Gravity Probe B,” Society of Photo-Optical Instrumentation Engineers, 1986. C. W. F. Everitt, “Gravity Microgravity..., “Cryogenic Star-Tracking Telescope for Gravity Probe-B,” SPIE Proceedings, Vol. 619, Los... Science Data Extraction for the Gravity Probe-B Gyro and Telescope," SPIE Proceedings...,” 1986. J. P. Turneaure, C. W. F. Everitt, B. W. Parkinson, “The Gravity-Probe-B Relativity Gyroscope Experiment: Approach to... Science Publishers 1986. Staff of Gravity Probe B at Stanford University, “Papers on... Stanford Relativity Gyroscope Experiment (NASA Gravity Probe B),” SPIE Proceedings, Vol. 619, January..., 1987. B. W. Parkinson, C. W. F. Everitt, J. P. Turneaure, “The Gravity Probe B Relativity Gyroscope Experiment: An Update... of Sputter Coatings for the Gravity Probe B Gyroscope Housings,” Proceedings of the..., 1988. J. P.Turneaure, et al., “The Gravity Probe B Relativity Gyroscope Experiment: Development of..., J. V. Breakwell, C. W. F. Everitt, “Contribution of the Gravity Probe B Mission to Geodesy and to... D. Bardas, M. A. Taber, et.al., “The Gravity Probe B Relativity Gyroscope Experiment: Preparations for... and Cryogenic Operation in the Gravity Probe B Relativity Gyroscope Mission,” The First... Press. C. E. Cohen, G. M. Keiser, B. W. Parkinson, “Tracking Gravity Probe B Gyroscope Polhode Motion,” AIAA Guidance... Integrated System Tests of the Gravity Probe B Experiment.” The First William Fairbank... al., “Gradiometry Coexperiments to the Gravity Probe B and STEP Missions,” Adv. Space..., Advances in Astronautical Sciences. C. W. F. Everitt, “Gravity Probe B: I. The Scientific Implications,” Proceedings of...-1644, 1991* D. Bardas, et al., “Gravity Probe: II Hardware Development; Progress Towards...-29, 1991.* Y. M. Xiao, et al., “Gravity Probe B: III. The Precision Gyroscope,” Proceedings... programme to select a resin for Gravity Probe B composites.”Cryogenics 1991, Vol. 32...-Cu Sputter Films for the Gravity Probe B Gyroscope Housings,” Surface and Coatings... Inertial Reference System for the Gravity Probe B Mission,” Proceedings July 23-24... Digital Controllers with Application to Gravity Probe B,” presented at The 12th IFAC..., 1993. S. Buchman, T. Quinn, G. M. Keiser, D. Gill, “Gravity Probe B Gyroscope Charge Control Using Field.... H. Uematsu, B. W. Parkinson, J. M. Lockhart, B. Muhlfelder, “The Gravity Probe B ‘Niobium Bird’ Experiment Verifying the..., 1994. J. C. Mester, C. W. F. Everitt, B. W. Parkinson, J. P. Turneaure, “Gravity Probe B: Status and Flight Plans,” Proceedings... Measurement and Control for the Gravity Probe Gyroscopes,” Rev. Sci Instruments, Vol... gyroscope performance enhancement for the Gravity Probe B relativity mission,” Class. Quantum Grav... Gauthier, “Gravity Gradient Gyroscope Drifts in the NASA Relativity Mission/Gravity Probe A Experiment... 1996 M. A. Taber, D. Bardas, et. al, “Gravity Probe B Payload Verification and Test Program... Control for the Relativity Mission Gravity Probe B.” Proceedings of the 32nd COSPAR..., S. Wang, Y. Xiao, and P. Zhou “The Gravity Probe B Relativity Mission,” Proceedings of the..., M. Taber, “Ultralow Magnetic Fields and Gravity Probe B Gyroscope Readout,” Proceedings of the... Telescope and Guide Star for Gravity Probe B.” Conference proceedings for the 32nd..., L. Sands, P. Schweiger, “Development of the Gravity Probe B Payload.” Proceedings of the Eighth... Heritage of the Relativity Mission, Gravity Probe B.” Proceedings of the Eighth Marcel..., “The Expected Performance of the Gravity Probe B Electrically Suspended Gyroscopes as Differential... the Gyroscope Housings of the Gravity Probe Relativity Mission.” Proceedings of APS... and Trapped Flux Analysis in Gravity Probe B Experiment”, Journ. of Applied Physics... Selection Algorithm for the Stanford Gravity Probe B Relativity Mission.” The Institute of..., G. M. Keiser, “Data Analysis in the Gravity Probe B Relativity Experiment.” Proceedings of the... Cryogenic 3-Dimensional Flexible Circuit for Gravity Probe B Satellite Telescope Readout Electronics” submitted...,” 1999 2000 C. W. F. Everitt, et al, “Gravity Probe B: Countdown to Launch.” Year 2000... Integration in the NASA/Stanford Gravity Probe B Relativity Mission,” Proceedings of the... Trapped Flux Signal Analysis in Gravity Probe B Experiment,” Physics Undergraduate Honors Thesis..., “Operational Cryogenic Experience with the Gravity Probe B Payload.” To be published in... General Relativity” (0.2milliarcseconds per year), Gravity Probe B Stanford University. Presentation at the... B. Muhlfelder, J. M. Lockhart and G. M. Gutt, “The Gravity Probe B Gyroscope Readout System” 2003 COSPAR..., M. T. Sullivan, K. Triebes and J. A. Lipa, “The Gravity Probe B Star Tracking Telescope,” Adv. Space... and J. P. Turneaure, “Science Telescope for Gravity Probe B,” Proceedings of SPIE Vol. 5172..., G.M. Keiser, “ Classical Torque Errors in Gravity Probe B Experiment”, Nonlinear Gravitodynamics. The Lense..., A.S.Silbergleit, G.M. Keiser, “Data Reduction in Gravity Probe B Experiment: Optimal Estimation and Filtering...



Дата загрузки: 2017-01-30
Скачать документ
0.23/5
...-10049-y Vol. 32, N. 11 2009 Gravity Probe B(∗ ) G. M. Keiser(1 ), M. Adams(1 ), W. J. Bencze(1 ), R. W. Brumley(1 ), S. Buchman... preliminary data analysis for the Gravity Probe B satellite. 556 560 560 562... 570 570 572 572 1. 2. 3. Introduction Gravity Probe B flight hardware . 2 1. Gyroscope . 2 1.1. Gyroscope readout... block metrology frame . 2 4. Low-temperature probe . 2 5. Superfluid liquid-helium dewar... Air Force Base carrying the Gravity Probe B satellite. Six of the nine.../y), while the orbital average 557 GRAVITY PROBE B Fig. 1. – Geodetic and frame dragging... then (1.2) dL = Ω × L. dt For the Gravity Probe B gyroscopes, the fractional differences.... 2. – Comparison of conventional gyroscopes with Gravity Probe B gyroscope. predicted magnitude is 0.039... required bias stability of the Gravity Probe B gyroscopes. For ring laser and.../h. The design goal for the Gravity Probe B gyroscopes was an uncompensated bias... to the a mass unbalance torque GRAVITY PROBE B 559 is 0.1 marcsec/y (0.5 nrad/y) for... of the challenges involved. The Gravity Probe B gyroscopes, payload, and satellite were... in 100 hours. For the Gravity Probe B gyroscopes, the required readout noise..., the readout noise of the Gravity Probe B gyroscopes will be significantly..., or, in the case of Gravity Probe B, having a drift rate small enough... star-tracking telescope on the Gravity Probe B satellite. If the guide star..., 2004, flight operations on the Gravity Probe B satellite included initial calibrations of... expected in 2010. 2. – Gravity Probe B flight hardware The Gravity Probe B gyroscopes were designed to...-temperature probe, which served as a vacuum container. The entire probe assembly was... of one of the four Gravity Probe B gyroscopes is shown in fig. 3. The... lapping heads and an GRAVITY PROBE B 561 Fig. 3. – The Gravity Probe B gyroscope. alumina slurry... spin axis will continually follow GRAVITY PROBE B 563 Fig. 4. – Gyroscope readout. the... moments of inertia of the Gravity Probe B gyroscope were typically less than... several important consequences for the Gravity Probe B experiment. First, to maintain the... at a 5 samples/s rate. Since the Gravity Probe B measurement requires such accuracy and... the corresponding voltage applied GRAVITY PROBE B 565 Fig. 5. – Gravity Probe B cryogenic telescope. to the... four windows in the cryogenic probe (discussed below). The light from... bonding technique was developed for Gravity Probe B and produced bonds of high... direction to the guide star. GRAVITY PROBE B 567 Fig. 6. – The science instrument... probe. – The fused-quartz block was mounted on the lowtemperature vacuum probe... described below. This low-temperature probe also included provisions for the... the vacuum probe. The overall gas conductance of the vacuum probe was... turned off, the pressure within the probe reached a level of approximately 10..., R. W. BRUMLEY, ETC. Fig. 7. – The vacuum probe with the science instrument assembly... dewar . – The low-temperature vacuum probe was inserted into a 2300 L super... instrument assembly and low-temperature probe GRAVITY PROBE B 569 Fig. 8. – The superfluid... from entering the low-temperature probe, a motor driven shutter was mounted..., W. J. BENCZE, R. W. BRUMLEY, ETC. Fig. 9. – The Gravity Probe B spacecraft. to determine the position... continued to function 24 hours a GRAVITY PROBE B 571 day, it was clear... TDRSS satellites relative to the Gravity Probe B satellite, and the available contact... residual gas pressure within the probe, and the final alignment of... described in more detail below. GRAVITY PROBE B 573 Initial tests of the... coarse attitude control for the Gravity Probe B spacecraft relied on the star... position and velocity of the Gravity Probe B spacecraft was determined at 10... general relativity for the actual Gravity Probe B orbit, and an independent estimate... the polar orbit for the Gravity Probe B satellite was selected was to... the orbit plane, then this gravity gradient force on each of... selected so that the average gravity gradient perturbation along with the... boil-off gas from the liquid- GRAVITY PROBE B 575 helium dewar increases from... pressure within the low-temperature probe. The final spin speeds of..., the interior of the vacuum probe, and the sintered titanium cryopump... the total gyroscope readout signal. GRAVITY PROBE B 577 Fig. 10. – Polhode period... depletion of the liquid helium. GRAVITY PROBE B 579 4. – Analysis of flight data... data was collected from the Gravity Probe B satellite during its year and... of the aberration of 581 GRAVITY PROBE B starlight due to the orbital... the Sun, and the parallax GRAVITY PROBE B 583 Fig. 13. – History of... in the West-East direction. GRAVITY PROBE B 585 maneuver to a nearby star... (the radial component) and the GRAVITY PROBE B 587 Fig. 16. – Radial drift... of the Gravity 588 G. M. KEISER, M. ADAMS, W. J. BENCZE, R. W. BRUMLEY, ETC. Probe B satellite, a contribution... Siddall G. J., Precis. Eng., 2 (1980) 123. GRAVITY PROBE B [23] [24] [25] [26] [27... Assembly Alignment Requirements, S0376 Rev. A (Gravity Probe B, Stanford University) June 17, 2001...