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  Guidance, Navigation, and Control

Genesis maintains its orientation in space, or "attitude," by continuously spinning in space. The attitude control system will keep Genesis spinning at a rate of 1.6 revolutions per minute. During the science mission, the axis of spin pointed 4 degrees ahead of the Sun, so that ion and electron monitors would face directly into the oncoming solar wind. The slow spin helps maintain inertial pointing at the Sun, and minimizes pointing errors due to solar radiation pressure torques. Genesis determines its orientation at any given time using a star tracker and Sun sensors.

Genesis is the first robotic spacecraft to fly this particular system to determine its orientation, or "attitude." The star tracker can track stars of third magnitude or fainter; in combination with the digital Sun sensor, it can identify stars and generate information on the spacecraft's attitude. Using both the angles of the Sun and of nearby stars, on-board software can determine the spacecraft's orientation and spin rate. As long as the spacecraft is spinning between 1.6 and 2 revolutions per minute, it can identify stars. During the maneuvers when the spacecraft is spinning faster than 2 rpm, the spacecraft will use its spinning Sun sensors to determine its orientation. There are two star trackers, two digital sun sensor and two spinning sun sensors onboard as redundant backups.

The guidance, navigation and control subsystem weighs 10.0 kilograms (22.0 pounds). button
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Curator: Aimee Meyer
Updated: November 2009

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