Rate Sensor Unit - The gyroscopes are part of Hubble's pointing system. They provide a frame of reference for Hubble to determine where it is pointing and how that pointing changes as the telescope moves across the sky. They report any small movements of the spacecraft to Hubble's pointing and control system computers. The computers then command the spinning reaction wheels to keep the spacecraft stable or moving at a desired rate. The gyroscopes work by comparing Hubble's motion relative to the axis of the spinning masses inside the gyroscopes. In the absence of external forces, these axes remain stable relative to the fixed stars in the sky. By keeping Hubble fixed relative to these axes, Hubble stays stable relative to the stars
RidgeStar Service Unit is a numerical value representing the relative cost for providing a particular Resource to a Client
Remote Switching Unit. An extension of a larger digital telephone exchange, in which a number of telephone lines (in groups of up to 256) can be located remotely from the main exchange and connected via a transmission system.
Road-Side Unit. The roadside infrastructure component of an ETC system; a receiver or transceiver that identifies the On-Board Unit in the vehicle, and identifies the account, permitting an electronic toll transaction to occur. Also called a ‘reader,â€(tm) or ‘beacon.â€(tm)
