Book excerpt: The devices installed in a space rocket can be divided into three classes: 1) an observing device used to observe physical phenomena in a high-altitude atmosphere and a counting device used to detect the operational condition of a rocket, 2) a teletransmitter used to send observed data to the ground stations, and 3) a radar transmitter to give instantaneous information about the trajectory of a space rocket. Of course, a rocket has equipment in addition to these three fundamental devices in order to ensure all devices and the flight operating efficiently and effectively. Some special techniques are needed to obtain an effective flight for a space rocket having all those measuring and counting and communication devices on board. And some other techniques are needed to get effective operation of the measuring and communication devices. For example, we have to open a window on the nose of the rocket to expose a measuring device to the outside atmosphere, or stretch out an antenna to send radio waves to ground stations. All techniques described here will be under the general heading of device- operation techniques. In the following sections, we shall see the achievements of device- operation techniques; and the author's personal opinion on the future trend of development in the technical field will be briefly described.