Commercial Communication Satellite Systems

Several communications satellites were launched by the United States, the former Soviet Union, Japan, and European countries between 1970 and 2000. It is impossible to describe the capabilities and battery power requirements for so many satellites within this chapter. Therefore, only select communications satellites will be described with an emphasis on their battery power requirements. 

The United States launched an advanced communications satellite known as the INTESAT-IV system in the 1990s, which represented a fourth-generation commercial communications satellite, incorporating the latest radiofrequency and digital components with minimum weight, size, and power consumption. This system offers specified communications service requirements and can be used in support of future manned space flight missions. Frequency operating bands and secondary battery power requirements for this particular communications satellite are summarized in Table 2.15. 

These power estimates assume a traveling wave tube amplifier (TWT A) efficiency of 30% for S-, C-, and X-band units and 25% for the Ku-band unit. To 

1 Performance Capabilities of the Commercial Communications Satellite System 

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Li-ion/UCAP hybrid systems with high power and long hfe would benefit multiple military and commercial communication satellite applications as well as selected Hybrid Electric Vehicle (HEV) and Electric Vehicle (EV) applications. 

The technology developed for radio astronomy is virtually the same as that used for commercial communication receivers. Therefore, many of the advances in radio astronomy have commercial applications in the form of smaller, more sensitive, and less expensive satellite communication equipment. Many satellite communication companies keep abreast of the developments in radio astronomy technology to adapt this technology to produce better communication systems. 

Battery requirements are stringent for certain commercial and most military applications. For commercial aircraft, helicopters, communication satellites, and military jet fighters and bombers, sealed Pb-acid and vented Ni-Cd rechargeable batteries are highly desirable to meet system reliability and critical performance requirements under severe temperature and mechanical environment. The performance improvement of a rechargeable battery is strictly dependent on the electrochemical technology. 

Battery power requirements to some extent depend on the mass of the satellite, which includes the weight of microwave transmitters, receivers, antennas, signalprocessing equipment, electronic sensors, onboard electrical appliances, solar panels and associated components, and the stabilization system. Two distinct types of stabilization system design configurations and associated components for satellite control are shown in Figure 2.6. Table 2.12 summarizes the battery power requirement and other critical parameters of commercial and military communications satellites. 

For non-volatile random access memories (NV-RAMs in which the stored information is retained even if power to the chip is interrupted), ferroelectrics serve not just as capacitors (as in the case of the DRAM, described below), but as the memory element itself. Their principal advantages in this application are low-voltage (1.0 V) operation, small size (about 20% of a conventional EEPROM cell - and cost is proportional to size once high-yield production is achieved), radiation hardness (not just for military applications but also for satellite communications systems) and very high speed (60 ns access time in commercial devices, sub-nanosecond in laboratory tests on single cells). 

The first QKD prototype operated over a distance of 32 cm in free space [147], Since then, experimental techniques have undergone a tremendous progress and today QKD systems at almost a commercial level are offered [165], A number of problems must have been solved. Communication distance has reached several tens of kilometers in optical fibers [166-169]. Also, free-space systems are being developed with earth-satellite communication on mind [170], It should be noted that only a few systems presented until now have exhibited parameters that would ensure a secure key generation. 

Innovation is an often misused word. Economists have defined an innovation as the first commercial application of a new or improved process or product. Nowadays, we should extend this to include a service or a system—the supermarket, time-shared computer, satellite communications, etc. I have discussed the nuances of the words innovation, invention, entrepreneurship, etc., and their interrelationships in a recent article. Therefore, if the innovation is in an area which must be preceded by inventive investigation of the R D type, the innovation comes into being when the results of the R D are first commercialized, usually by investing capital, thus converting the cost of the R D into an economic benefit (lower manufacturing costs, higher profitability, new or improved products, etc.). 

Dr. Jha has authored 10 high-technology books and has published more than 75 technical papers. He has worked for companies such as General Electric, Raytheon, and Northrop Grumman and has extensive and comprehensive research, development, and design experience in the fields of radars, high-power lasers, electronic warfare systems, microwaves, and MM-wave antennas for various applications, nanotechnology-based sensors and devices, photonic devices, and other electronic components for commercial, military, and space applications. Dr. Jha holds a patent for MM-wave antennas in satellite communications. 

Cellular mobile telephony is only one means of mobile communications there are other technologies such as satellites, cordless telephones and pagers which competed against cellular telephony. In contrast to the commercially successful mobile cellular telephony, these other systems of personal mobile communications failed... 

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