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Fiche 1,  Justifications,  Français

Fiche 1,  Justifications,  Espagnol

Fiche 2,  Justifications,  Anglais

Record number: 2, Textual support number: 1 CONT

The calculations for the ISS [International Space Station] quasi-steady acceleration environment can be compared to a set of formal design requirements which state that 50 percent of the ISPR [International Standard Payload Rack] locations within the U.S. Lab, Columbus and the JEM must have quasi-steady accelerations below 1 ug for periods of 30 continuous days a total of 6 times per year. The operation of the Station in Microgravity Mode is designed to produce these 30 day intervals. The quasi-steady acceleration vector has an additional directional stability requirement stating that the component perpendicular to the vector’s orbital average must be less than or equal to 0.2 [mu] g. To meet this requirement the Station’s attitude must be controlled during orbit so that it maintains a constant position relative to the LVLH [Local Vertical/Local Horizontal] axes.  2, fiche 2, Anglais, - quasi%2Dsteady%20acceleration%20environment

Record number: 2, Textual support number: 2 CONT

The quasi-steady state acceleration level is determined primarily by the combined effects of atmospheric drag(due to the finite residual Earth's atmosphere at the orbital altitude of the ISS), and gravity gradient stabilisation of the ISS. Gravity gradient stabilisation uses the principle that a body in orbit around the Earth will tend to rotate about it's centre of mass, as each part of the body will tend to follow it's own orbit. It will normally oscillate about a mean orientation, but will eventually remain in a stable orientation with respect to the Earth. The normal orientation for the ISS is the Torque Equilibrium Attitude discussed earlier. The resultant combination of atmospheric drag, gravity gradient and other secondary effects produce a set of gravity contours(i. e., locations of equal gravity level) which define the quasi-steady state microgravity environment of the ISS.  3, fiche 2, Anglais, - quasi%2Dsteady%20acceleration%20environment

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quasi-steady acceleration environment: term officially approved by the International Space Station official approval Group (ISSOAG).  4, fiche 2, Anglais, - quasi%2Dsteady%20acceleration%20environment

Fiche 2,  Justifications,  Français

Record number: 2, Textual support number: 1 OBS

Les modèles d'analyse dynamique (DAC 8) pour l'ISS [International Space Station] prévoient un environnement caractérisé par des vibrations de l'ordre du milli-g (10-4 g) plutôt que des conditions de véritable microgravité (10-6 g) en raison des activités et des divers éléments de l'ISS qui causent des vibrations intempestives (gigue gravitationnelle). Les travaux antérieurs menés à bord de la navette et de Mir ont montré que le milieu est caractérisé par des vibrations aléatoires continues, orientées dans tous les sens, avec des accélérations de l'ordre du milli-g et des crêtes dépassant souvent les 10 milli-g.  2, fiche 2, Français, - milieu%20gravitationnel%20quasi%20stable

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milieu gravitationnel quasi stable : terme uniformisé par le Groupe de travail de la terminologie de la Station spatiale internationale (GTTSSI).  3, fiche 2, Français, - milieu%20gravitationnel%20quasi%20stable

Fiche 2,  Justifications,  Espagnol

Fiche 3,  Justifications,  Anglais

Record number: 3, Textual support number: 1 OBS

A passive gravity gradient attitude control system developed by General Dynamics/Astronautics.  1, fiche 3, Anglais, - Vertistat

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The "Vertistat," a satellite passive attitude control system.  2, fiche 3, Anglais, - Vertistat

Fiche 3,  Justifications,  Français

Fiche 3,  Justifications,  Espagnol

Fiche 4,  Justifications,  Anglais

Record number: 4, Textual support number: 1 CONT

Inside an orbiting spacecraft a "microgravity" environment exists in which the acceleration of objects and persons relative to their surroundings is reduced to the level of micro g’s ...  2, fiche 4, Anglais, - microgravity%20environment

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Even in a gravity gradient attitude, accelerations caused by crew movements, equipment operations, and occasional thruster firings can disrupt the quiescent low-gravity environment and may affect microgravity science experiments. Accelerations at particular frequencies may interrupt one type of experiment but have no effect on others. These accelerations are measured at fractions of Earth's gravity; for instance, 10~ g is equal to 1/100, 000 of the gravity on Earth.  3, fiche 4, Anglais, - microgravity%20environment

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microgravity environment: term officially approved by the International Space Station official approval Group (ISSOAG).  4, fiche 4, Anglais, - microgravity%20environment

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Vibratory microgravity environment.  4, fiche 4, Anglais, - microgravity%20environment

Fiche 4,  Justifications,  Français

Record number: 4, Textual support number: 1 CONT

Un environnement en microgravité offre aux scientifiques une occasion unique de contrôler les phénomènes liés à la gravité. De plus, en microgravité, le traitement sans contenant peut être pratiqué sur de plus gros échantillons, car les force acoustiques et électromagnétiques utilisées pour manipuler ne sont pas dominées par la gravité.  2, fiche 4, Français, - environnement%20en%20microgravit%C3%A9

Record number: 4, Textual support number: 1 OBS

environnement en microgravité : terme uniformisé par le Groupe de travail de la terminologie de la Station spatiale internationale (GTTSSI).  3, fiche 4, Français, - environnement%20en%20microgravit%C3%A9

Fiche 4,  Justifications,  Espagnol