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

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Gravity Probe Clock – Probing the gravitomagnetic field ... Earth. This mission is called Gravity Probe C. Gravity Probe C(lock) is based on a recently... perform Gravity Probe C is expected to be comparable to that of the Gravity Probe... Within our solar system relativistic gravity theories can be tested only... universe. It follows that relativistic gravity experiments in the solar system.... In order to describe relativistic gravity on macroscopic scales we usually... the main objective of the Gravity Probe B–mission which is awaited to..., in the following called Gravity Probe C, which, similar to Gravity Probe B, is designed to... the objective of Gravity Probe C. An experimental realization of Gravity Probe C is expected to... of numerical integration. 3 Realization of Gravity Probe C In principle, it is a trivial... relative gravitomagnetic precession angle of a Gravity Probe B–gyroscope: The precession angle ΩP (per... the Gravity Probe C mission is essentially equivalent to that of Gravity Probe B. 3.1 Mission design Gravity Probe C is simple from a conceptual point of view. To perform Gravity Probe... orbiting clocks in space. Therefore, Gravity Probe C could rely, in principle, on... we now assume a realization of Gravity Probe C in the form of atomic...−9 g − 10−10 g. NASA’s already approved gravity mapping mission GRACE is expected... considerations of this section that Gravity Probe C requires high precision measurements. Overall... Gravity Probe C might be obtained as a by–product of other space missions. Gravity Probe... showed us their interest in Gravity Probe C. In particular we would like..., G. Sch¨afer. The physics behind Gravity Probe C was kindly shared with us... 35 years to realize the Gravity Probe B mission. 8 References [1] H. Stephani: General Relativity.... Sci. U.S.A. 46 871 (1960). [4] G.M. Keiser: “Gravity Probe B”, Lecture given at the Alpbach...



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..., by the NASA-DLR (Germany) Gravity Recovery and Climate Experiment (GRACE... be committed to the Lisa gravity-wave detector, which depends heavily... carry 16 instruments. Using lunar gravity-assist swingbys, they were subsequently... arm’s performance at Earth-normal gravity. Following the flight the teachers... One aircraft operated by Zero Gravity Corporation (USA) from airstrips in..., San Diego, and Washington. Zero Gravity Corporation also conducted five workshops... and for ionosphere, climate and gravity research. Data from the satellites....” J. L. Chen et al. 2006 ‘Satellite Gravity Measurements Confirm Accelerated Melting of... 2006): “Using timevariable gravity measurements from the Gravity Recovery and Climate Experiment..., terrain camera, radar sounder), for gravity studies (VLBI and data relay... orbit in 2009, after multiple gravity assists, to undertake global mapping... combination of electric propulsion and gravity assists, the planned cruise duration... Jupiter in early 2007 for a gravity assist and for scientific studies... variation, albedo, spectrum, mineral composition, gravity, and its main chemical composition... that the cratering process was gravity-dominated, supporting the notion that... to reach the cometary target, gravity assists (accompanied by science studies... study of the magnetic and gravity fields with unprecedented precision, and.... Small-Scale Waves. Small-scale gravity waves play a critical role in... the middle atmosphere. Accurately parameterizing gravity waves in global circulation models... in gravity wave studies include the construction of a climatology of gravity wave... a French and Australian collaborative project, gravity-wave parameters are being extracted... in the mesopause region, and gravity wave activity. The Arecibo Observatory... studies of the evolution of gravity waves, from their excitation level... programme was designed to study gravity wave dynamics and forcing of... revealed considerably greater variability in gravity wave, and in larger-scale... images showing the effects of gravity wave activity and PMC particle... filtering of gravity waves by allowing more eastward-flowing gravity waves to... significantly by changes in gravity wave filtering and gravity wave forcing around... from the variability of the gravity wave sources, planetary waves and...-generated gravity waves are parameterized while a spectrum of non-stationary gravity waves... suppresses the breaking of parameterized gravity waves above about 100 km... by the parameterized non-orographic gravity wave drag. A similar mechanism appears... MLT region without a gravity wave parameterization, but resolved gravity waves in the... with MM5 simulations. In addition, gravity wave instabilities were studied both... and Space Biology focuses on gravity perception, genetic and physiological modifications... response to microgravity or simulated gravity. Genetic studies are typically paired... to understand the effect of gravity on development, generative and vegetative... gravitational loads. The study of gravity perception mechanism and of related... responses and intricate patterns of gravity-dependent processes. Because of the... space exploration. The European Low Gravity Research Association (ELGRA), which is... the way in which reduced gravity affects many physiological systems, including... these systems adapt to a different gravity environment. For instance, even after... when the crew reenters a higher gravity environment, as found on the... of materials. In microgravity, these gravity-driven phenomena are significantly suppressed... be carried out in a ‘zero’ gravity environment, extremely long path lengths... circumstances include the study of gravity and gravitational waves, tests of... launch and successful operation of Gravity Probe B on 20 April 2004. The... fields of geopotential modelling (Earth’s gravity and magnetic fields), oceanography (altimeter... of dynamic models, the Earth’s gravity field in particular. The continuous... (dynamic, reduced-dynamic, kinematic) and gravity field determination (global, local). Significant... modelling the Earth’s (pseudo-static) gravity field with unprecedented precision and... making use of space-borne gravity gradiometry, based on an instrument... Mars orbiters and in conjunction gravity field modelling of these celestial... gravity field models and even to observe temporal variations of Mars’s gravity... first time, the global lunar gravity -193- field (including the far..., the description of shorter-scale gravity waves above Antarctica, and the... geophysical data (e.g. atmospheric, ionospheric, geomagnetic, gravity) through the establishment of a series... Pluto and Charon, with a Jupiter gravity assist (and Jupiter observations) planned... Incoherent Scatter Radar European Low Gravity Research Association Environment Satellite Earth... and Spectroscopic Explorer (NASA) Earth gravity Global Astrometric Interferometer for Astrophysics... (Russia) Global Navigation Satellite System Gravity field and Ocean Circulation Explorer... of Stars Gravity Probe B Global Plasmasphere Ionosphere Density Global Positioning System Gravity Recovery...



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... THE SOLAR SYSTEM . . . . . 59 Earth’s Gravity Well (61) The Exploration of... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 Earth Spaceport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 Variable Gravity Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 Tethers in Space... pacing problems that depend on gravity. Particularly needed are long-duration... one-sixth gravity of the Moon, and the one-third gravity of... from radiation, and probably some gravity. Technological advances will permit all... with little energy, and artificial gravity can be provided by rotation... at less than Earth-normal gravity, requires more knowledge and the..., and • Space tethers and artificial gravity These base technology and demonstration...? • What is the importance of gravity in physical, chemical, and biological... satellite. (Courtesy M. Chahine and J. Susskind) Gravity field of the world’s oceans... gravity from less than a hundred-thousandth to greater than one Earth gravity by using centrifugal force in a rotating system or by a gravity... a weakened skeletal structure to increased gravity when, for example, humans emerge... than in the past, including gravity, radiation exposure, environmental toxicology, nutrition... space and in controlled artificial gravity at levels between zero and... billions of years under Earth-gravity conditions. Studying its response in... both plants and animals to gravity. 35 Physics, Chemistry, and Biology... accurate results than desired. Reducing gravity by a factor of 100,000... and quantify the effects of gravity on the development, adaptation, and... ground-based research in normal gravity; and new tests of general... experiment in Earth orbit called Gravity Probe B will measure the precession of... of energy. INNER SOLAR SYSTEM GRAVITY WELLS 62 Astronaut Gene Cernan... “cycler” they will experience a rotational gravity somewhere between that of Earth... elements, the energy of sunlight, gravity, and protection from radiation. All... on planetary surfaces, although normal gravity is available only on Earth... space environment, where Earth-normal gravity can be provided by rotation... material requirements: air, water, food, gravity, and protection from cosmic and... inner Solar System. In space, gravity’s equivalent can be provided by...” questions of air, water, food, gravity, and protection from radiation. For...: Normal intensities of sunshine and gravity, a normal day/night cycle, the... heavier than the other and gravity causes separation into two layers..., however, because the effects of gravity are reduced there a millionfold. Controlled... to develop artificial gravity technology, including centrifuge, tether, and gravity-gradient techniques... rotate about a common center of gravity. Such tethers have myriad potential... maintaining propellant tanks at partial gravity for safe storage and ready... a spaceport in low orbit, a variable gravity, research facility, and spaceports in... between Worlds before 2010. Variable Gravity Research As previously noted, early... for humans experiencing Earth-normal gravity simulated by rotation? (See page... questions must be answered. What gravity level is needed to present... return from low g to Earth gravity? Experiments to settle these questions.... In the background is a Variable Gravity (g) Research Facility that will be... of bodies moving through central gravity and magnetic fields. They can... transportation. The generation of artificial gravity via tethers offers another class... together will experience an artificial gravity proportional to their distance from... hundreds of miles, allowing controlled gravity fields up to about 0.2g.... [more...] For this work a variable gravity research facility is required. In... on the effects of low gravity in many scientific disciplines. Thus... structure, and can alter synthetic gravity by varying spin rate via... exposure to less than Earth’s gravity must be fully understood. In... periods of time in low-gravity environments. NASA’s experience suggests that... required 45 days of Earth gravity before muscle coordination allowed them... one-sixth gravity of the Moon, or the one-third gravity of... a variable gravity research facility, the rotation rate and the gravity level will... subsystems. This facility must establish gravity level requirements in time to... which the Gravity of the Earth is Cancelled by the Gravity of... earlier structure, will have artificial gravity. In the case of Mars... all be provided with artificial gravity. Spaceship mass can be reduced... required are: • Earth Spaceport • Variable-Gravity Research Facility; and • Lunar Surface... by NASA. 148 The Variable-Gravity, Research Facility is required within... to understand the required artificial gravity levels necessary for long-duration... simulate various levels of artificial gravity. They should be accessible to...: An extremely low level of gravity. As experienced by shuttle crews..., one millionth the level of gravity on Earth’s surface. Orbital Maneuvering...



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... STS mission used the low gravity of space to improve separation... light on the responses to gravity. Spacelab 2 and 3, planned for 1984... dwarf star, advanced ability to probe the interiors of white dwarfs... plates and the earth’s global gravity and magnetic fields also seek..., length of day, and the gravity and magnetic fields are contributing... weather and climate. The earth‘s gravity and magnetic fields offer two... commercial use of the low gravity of space to improve the... years; but the effects of gravity, primarily sedimentation and buoyancy of..., reduce efficiency. Operation in low gravity during the Shuttle flight yielded... to see how very low gravity affects growth movements. The European... (auxin) modifies plant response to gravity. Understanding the mechanism in physiological... carried on a highaltitude balloon and a probe rocket. The infrared data on... capability for the Galileo orbiter-probe mission to Jupiter in 1986... short-range attack missiles and gravity weapons through fiscal 1986. Beginning... geodynamics. Studies of the proposed gravity satellite - GRAVSAT- system indicate that... concept of determining the global gravity field of the earth by... improve knowledge of the earth's gravity field by 10 times or... the hydrogen. Studies of Low-Gravity Effects ’ Materials Processing in Space... an expected great reduction in gravity-driven convection. Sufficient reduction in... has been collaborating on NASA’s Gravity Probe B experiment to test the theory... will be performed in a nearzero-gravity environment in space, where it... liquid specimen in near-zero gravity is being tested in preparation... Droplets. The effect of diminished gravity on nucleation in the liquid... mass spectrometer for the Galileo probe (flight unit). Machining requires very... anelastic model convection and acoustic-gravity waves. Data obtained with the... oscillations can be used to probe subphotospheric cellular structures. Theoretical models... an orbiter spacecraft with atmospheric probe to Jupiter. The solar polar... selected sites and an extensive gravity data set. These data and... solar-powered portable meteorological monitoring (PROBE) stations support SCPP, CREST, the... fully implemented, AERA would automatically probe aircraft routes, detect and resolve... by others, astrophysicists can now probe the interiors of white dwarfs... balance required to cool atmospheres. Gravity Research SAOs hydrogen maser group... doppler system in a deep space probe. With today’s precise timing and... zero gravity, formation of crystals in weightlessness, and convection in zero gravity...



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...ös (1 E = 10 ---9 s ---2). The linear gradient of gravity is defined in units of... gradient in the acceleration of gravity with horizontal distance. Erlang . . . . . . . . . a dimensionless... acceleration (used in particular in gravity measurements): 1 gal = 10 ---2 m s ---2 = 1 cm s ---2; 1 mgal... acceleration of gravity g. Variations in the acceleration of Earth’s gravity (e.g. gravity anomalies) are... ---3 g) milligal  10 ---6 g (where “g” is the gravity constant) millijoule (10 ---3 J) milliliter (10... microgal  10 ---9 g (where “g” is the gravity constant of 9.81 m/s2) micrometer... Livermore, CA Department of Defense Gravity Experiment (M.10) Digital Object Identifier... of NASA and NASDA Earth Gravity Model 1996 (developed at NASA... is based on surface gravity data, altimeter--derived gravity anomalies from ERS... Asian Monsoon Experiment (campaign) GAMES . . . . . . . . Gravity and Magnetic Earth Surveyor (a NASA... spacecraft: Wind and Polar) GGSE . . . . . . . . . Gravity Gradient Stabilization Experiment. A technology satellite...): launch May 31, 1967 GGTS---1 . . . . . . . Gravity Gradient Test Satellite---1 (of the... . . . . . . . Gotland Basin Experiment (campaign) GOCE . . . . . . . . . Gravity Field and Steady---State Ocean... of Aviation Systems (Moscow, Russia) Gravity Probe---B Relativity Mission (E.12) Global Precipitation... Development Test Objective (Shuttle payload) Gravity Recovery and Climate Experiment Ground...---altitude environmental monitoring. A German space probe of DFVLR, launched Dec. 10... into a solar orbit. A German space probe of DFVLR, launched Jan. 15... in 1966), Pioneer (Venus Probe, 1978), Galileo (Jupiter Probe, launch 1989). Military... civil (TIROS, AM---1, ISS, HST, Gravity Probe---B, Wind, Polar, Landsat---7, TRACE, etc... Alpine Programme (campaign) Microwave Anisotropy Probe (NASA S/C mission within the MIDEX... of Defence (London, UK) Middeck 0---Gravity Dynamics Experiment (Shuttle payload) Magneto... . . . . . . . . . . . . PRIMA . . . . . . . . PrioraNet . . . . . . . PRIRODA . . . . . PRN . . . . . . . . . . . PRNU . . . . . . . . . PROBE . . . . . . . . PRODEX . . . . . . ProSEDS . . . . . . . PROTEUS . . . . . PROTEUS . . . . . PSI... Photodetector Quadrifilar Helix (antenna) Quantum Gravity Gradiometer (based on atom interferometer... academia. SGG . . . . . . . . . . . Satellite Gravity Gradiometry SGGM . . . . . . . . . Superconducting Gravity Gradiometer Mission, NASA (SGGM... study fluid dynamics in low gravity with FLEVO (Facility for Liquid... orbits for determining the Earth’s gravity field) SST . . . . . . . . . . . . Sea Surface Temperature... experiment on---board Spot---3 for gravity field studies of the Earth...



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..., 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...



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... 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...



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... depart with the Beppi-Colombo probe in 2012 (Composition of crust... that left with the Rosetta probe for a close encounter with a comet... measure variations in the Earth’s gravity, requires orbits that are accurate... to elucidate how a lack of gravity influences the disactivation of T-cells... high-precision clocks in zero gravity, aces should be 10 times... (eds.), SSSI Vol. 16 Earth Gravity Field from Space - from Sensors... nuclei. This allows us to probe the emission in regions of... will be very helpful to probe if 60% of the active... Galaxy provides a unique tool to probe the nucleosynthesis that occured in... of such a research is to 1. probe the connection between accretion (manifesting... and simulate observational parameters that probe the role of particle acceleration... stars. Differential emission measure distributions probe the distribution of plasma in... identify “windows of sensitivity” to gravity during the activation process; • to.... Due to the the micro-gravity environment, this clock is expected... atom clock in the micro-gravity conditions will be conducted. In... precise verification so far, the Gravity Probe A experiment (1976). In another test...: soho: Variability of Irradiance and Gravity Oscillations Solar and Heliospheric Observatory... velocities, earth rotation, the Earth’s gravity field, atmospheric parameters (water vapor... (navigation/positioning systems, altimeter satellites, gravity missions), detection and tracking of... periodic changes of the Earth’s gravity field in Zimmerwald. The Federal... the value of the Earth’s gravity in Zimmerwald using an absolute... techniques. For the European GOCE (Gravity Field and Steady State Ocean... km and measuring the Earth’s gravity field with an unprecedented accuracy... for a mapping of the Earth’s gravity field with unprecedented accuracy. The... Using the GPS”, in “Earth Gravity Field from Space - From Sensors... GPS Service Low Earth Orbiter Gravity Field and Steady State Ocean...



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... 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...



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... 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...