Circular Motion
Forces and Motion | Earth and Space

Yo-yo satellites

Stories from Physics for 11-14 14-16 IOP RESOURCES

Some satellites are deliberately spun about an axis perpendicular to their orbital plane in order to prevent their position drifting. As in a gyroscope, this provides some inertia against perturbations and angular velocities of between 30 and 100 rpm are typical. In an alternative application, a technique known as yo-yo de-spin has been used to slow the rotation of a satellite. Two masses attached to lengths of cord released from opposite sides of the craft, like the extended arms of a pirouetting skater, are used to cause the rotational velocity of the satellite to decrease. Yo-yo de-spin was used on early, unmanned space flights in the 1950s and on recent missions, including the 1999 Mars Polar Lander and the 2003 Mars Exploration Rover.

Circular Motion
can be analysed using the quantity Centripetal Acceleration
can be described by the relation F=m(v^2)/R
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