Abstract: A planar thermal radiator for use in outer space is disclosed. The radiator is adapted to rotate on two mutually perpendicular x and y axes which are in x and y planes respectively that are perpendicular to each other and to the planar surfaces of the radiator. It utilizes a plurality of pairs of heat sensors wherein each heat sensor provides a value of electrical resistance which is representative of the incident heat energy along the sensitive axis of that heat sensor. A common heat sensor pair detects incident heat energy which is perpendicular to the radiator. A first plurality of heat sensor pairs is used to detect incident heat energy along sensitive axes that are parallel to the x-plane and a second plurality of heat sensor pairs is used to detect incident heat energy along sensitive axes that are parallel to the y-plane. One sensor of each heat sensor pair is mounted on the opposite surface of the radiator. Each heat sensor pair has an associated heat sensor pair in its respective plurality.

Abstract: Optical communication system having repeater amplifiers cascaded with plurality of optical star couplers wherein each star coupler is coupled to an associated set of terminals. Each star coupler has two mixing sections serially disposed between its input and output terminal ports. Star couplers receive optical signals from their associated terminals, mix the received signals and retransmit the mixed signals to each terminal in its associated set and to each of the repeater amplifiers. Star couplers also receive amplified signals from the repeater amplifiers, mix the received amplified signal and retransmit the mixed optical signals only to their associated terminals. Star couplers, thus, enable optical signals transmitted by their associated terminals to be transmitted to each terminal in the system without permitting the same signal to be returned to the same star coupler, thereby avoiding the formation of continuous optical loops and hence avoiding the problem of optical lockup.

Abstract: Disclosed is an apparatus for protecting a three-phase power transmission line, having three power conductors, from intermembral electrical faults. First, second, and third sensing and rectifying means are inductively associated with respective ones of the three power conductors of the power transmission line for generating respective DC signals corresponding to the current flow through the respective, associated power conductors. A first switching means is provided for disconnecting the power transmission line from a power source upon the occurrence of a voltage imbalance between the sensing and rectifying means. Another switching means is provided for temporarily interconnecting the outputs of the sensing and rectifying means before operation of the first switching means, for preventing spurious tripping of the first switching means during sharp increases in power which do not occur as a result of a fault.

Abstract: A power controller for transmitting alternating current from a power input circuit to a load, the controller being a master silicon controlled rectifier, hereinafter the "master rectifier," and a slave silicon controlled rectifier, hereinafter the "slave rectifier," connectible in parallel with the load across the input circuit, a capacitor chargeable during positive half cycles for discharging at the zero voltage crossover between half cycles of positive and negative input voltage to render the master capacitor conductive and a second capacitor chargeable When the master controlled rectifier is conductive whose discharge renders the slave rectifier conductive at the instant of zero voltage crossover between half cycles of negative and positive input voltage.