Abstract: Apparatus and method for secure communication between an earth station and spacecraft. A laser outputs single pulses that are split into preceding bright pulses and delayed attenuated pulses, and polarized. A Pockels cell changes the polarization of the polarized delayed attenuated pulses according to a string of random numbers, a first polarization representing a "1," and a second polarization representing a "0." At the receiving station, a beamsplitter randomly directs the preceding bright pulses and the polarized delayed attenuated pulses onto longer and shorter paths, both terminating in a beamsplitter which directs the preceding bright pulses and a first portion of the polarized delayed attenuated pulses to a first detector, and a second portion of the polarized delayed attenuated pulses to a second detector to generate a key for secure communication between the earth station and the spacecraft.

Abstract: A circular, ziz-zag scan for use with vidicon tubes. A sine wave is generated, rectified and its fourth root extracted. The fourth root, and its inverse, are used to generate horizontal ramp and sync signals. The fourth root is also used to generate a vertical sync signal, and the vertical sync signal, along with the horizontal sync signal, are used to generate the vertical ramp signal. Cathode blanking and preamplifier clamp signals are also obtained from the vertical sync signal.

Abstract: A deicing system for applying a deicing mixture to an aircraft is provided. Water is enclosed in a first tank, and deicing fluid in a second tank. A first pump transfers water through a heater, to a heat exchanger located in the second tank. The deicing fluid is thereby heated to a desired operating temperature by the hot water flowing through the heat exchanger, with the flow of hot water controlled by a heater control device. The first pump and second pump transfer heated water and heated deicing fluid, respectively, to a mixing chamber. A mixing control means controls the respective flows to provide the desired mixture. The mixture of water and deicing fluid is then applied to the aircraft via a nozzle.