According to foreign media reports, the Israeli air force has officially received the "tears of the sky" tethered balloon developed by the country's Ministry of defense in cooperation with the US missile defense agency. This system can detect various types of targets and further improve the early warning and detection level of the Israeli air force. Balloon equipment has outstanding advantages Different from airships equipped with power equipment, tethered balloons are unpowered floaters, which mainly rely on buoyancy to lift off and stay, and are connected with ground anchoring facilities through tethering cables. Tethered balloons are generally composed of spheres, mission loads, tethered cables, anchoring platforms, ground control systems and other major components. Among them, the sphere is the system bearing platform, which is made of composite materials, and its shape is usually oblate or spherical. According to the size of the sphere, tethered balloons can be divided into micro, small, medium, large and super large. Generally, the larger the tethered balloon, the stronger the carrying capacity; The higher the altitude, the longer the dwell time. Mission loads are usually installed on the platform below the sphere, mainly carrying various types of loads such as communication, radar, optoelectronics and so on. Tether cable is the key component to control the launch, recovery, residence and attitude adjustment of tethered balloon. At the same time, it provides energy for the sphere and sometimes provides information transmission channel for balloon and ground system. The anchoring platform is responsible for the lifting, control and maintenance of the sphere. According to the application scenarios, it can be ground fixed, vehicle mobile and shipborne. Overall, tethered balloons mainly have the following characteristics. Long dwell time. Tethered balloons take off by buoyancy and have a long dwell time. Generally speaking, the dwell time of a single deployment of a large fixed tethered balloon can reach 30 days, and the dwell time of a single deployment of a small mobile tethered balloon can reach more than one week, while the man-machine is usually several hours and the UAV is dozens of hours. Wide coverage. According to the balloon size, it can be deployed to hundreds of kilometers. For small mobile tethered balloons, communication support and observation coverage of about 20 kilometers can be provided at 300 meters in the air, and large and medium tethered balloons with 4 kilometers in the air can monitor areas with a radius of 350 kilometers. Strong mobile deployment capability. The maneuvering deployment capability of tethered balloons mainly depends on its anchoring platform. For vehicle mounted mobile and shipborne mobile tethered balloons, there is no need for a fixed site, they have the function of vertical take-off and landing, have good adaptability to the deployment site, and have low requirements on the number and technical level of operators. They can be quickly transported and deployed to the designated area to perform tasks. High efficiency cost ratio. Compared with other air platforms, tethered balloons have the advantages of low cost and simple maintenance, and can adapt to land, air, sea and other environments. The large tethered balloon system can also carry multiple loads and perform more tasks at the same time. Broad prospects for military applications Tethered balloon is one of the earliest aircraft used in the battlefield, which was widely used in the Second World War. In recent years, with the development of related technologies, the performance of tethered balloons has made great progress. At present, the United States, Russia, Israel and other countries have the ability to independently develop and mass produce tethered balloons, and their development and application represent the current development level of tethered balloons. At present, the US military is equipped with different types of tethered balloons. Among them, 12m and 17m series tethered balloons are tactical equipment. For the land battlefield monitoring application of rapid deployment, withdrawal and redeployment, they have the characteristics of compact system and convenient operation. They can carry visible light, infrared and communication relay loads to provide information support for ground forces in complex terrain or remote areas. This kind of equipment has been successfully used by the U.S. military in the wars in Iraq and Afghanistan, and provides a patrol platform for the U.S. Customs and border patrol team. Russia is also a large country in the development and application of aerostat, with a relatively complete equipment spectrum. For example, the Russian "Puma" series tethered balloon is one of the largest tethered balloon equipment in the world. It can carry high-power radar and undertake the tasks of monitoring, identification and tracking within a range of 380 kilometers. Israel's "sky star" series are micro / small tethered balloons, which have been widely used in military and civil missions. As a tactical individual tethered balloon system, the volume of this series of tethered balloons is no more than 200 square meters. It can be integrated into small vehicles. It has the characteristics of strong mobility, easy deployment and simple release and recovery. It can use a portable control system for load control and application. (outlook new era)