What Are Satellites Used For?

Satellites for Communication

Broadcasting television

Satellites play a crucial role in transmitting television signals, both directly to households and as the foundation of cable and network TV. These devices distribute programming from a central station to smaller stations, which then transmit the signals locally via cables or the airwaves. Additionally, satellites facilitate "on-the-scene" news broadcasts, such as live reports on events like Capitol Hill votes or traffic accidents, by relaying footage from the field to the studio.

Telephones

Satellites enable in-flight phone communication on airplanes and serve as a critical communication link for rural regions and disaster-stricken areas where phone lines may be damaged. They also serve as the primary timing source for cell phones and pagers. In 1998, a satellite malfunction highlighted our dependence on these devices when it caused 80 percent of pagers in the United States to temporarily go silent. It also impacted National Public Radio's ability to distribute broadcasts to affiliates, leading to broadcasts being limited to the organization's website. Furthermore, during the CBS Evening News, the video feed of Dan Rather froze while the audio feed continued, illustrating the severity of the satellite failure

Satellites for Navigation

GPS: Navstar Global Positioning Systems

Satellite-based navigation systems, such as the widely recognized Navstar Global Positioning Systems (commonly referred to as GPS), make it possible for individuals with handheld receivers to determine their location with remarkable accuracy, within just a few meters. GPS locators are now commonplace in in-car navigation services and even utilized by car-sharing companies like Zipcar to locate their vehicles. Both civilians and the military rely on GPS-based systems for navigation on land, sea, and air, particularly in challenging scenarios such as ships navigating through inclement weather in a harbour or troops who are lost in unfamiliar terrain, where other navigation aids may be unavailable.

Satellites for weather and climate

Meteorological Satellites

Meteorologists rely on satellites to obtain a comprehensive view of global weather conditions. This allows them to track the impact of natural events, such as volcanic eruptions, and man-made activities, such as gas and oil field fires, as well as the development of large-scale phenomena, such as hurricanes and El Niño.

In addition, satellites are among the most valuable resources for climate change research. They can monitor ocean temperatures and currents, and data from radar-equipped satellites have demonstrated that sea levels have risen by an average of three millimeters per year over the past decade. Imaging satellites are also useful for assessing changes in glacier size, a task that is challenging to accomplish from the ground due to the remote and dark nature of polar regions. Satellites can also identify long-term patterns in rainfall, vegetation cover, and greenhouse gas emissions.

Satellites for research

Hubble Space Telescope

In the pre-Space Age era, astrophysicists were constrained to examine the cosmos solely through terrestrial telescopes, and thus, had access solely to data from the electromagnetic spectrum's sections that were capable of penetrating the Earth's atmosphere. However, numerous captivating phenomena are optimally scrutinized at frequencies that are primarily or exclusively reachable from space. Consequently, satellite telescopes have played a crucial role in comprehending occurrences such as pulsars and black holes and calculating the universe's age. Perhaps, the Hubble Space Telescope is the most indispensable astronomical instrument ever constructed.

Satellites for application

ATS Satellites

Under the leadership of Wernher von Braun and other supervisors, NASA initiated the Applications Technology Satellites (ATS) program in 1966. The aim of this program was to assess the feasibility of launching a satellite into geosynchronous orbit. These experimental satellites were primarily developed to serve as communication satellites. However, they also carried equipment designed for meteorology and navigation purposes.

ATS-6, in particular, was significant for being the world's first educational satellite. It also served as the first experimental Direct Broadcast Satellite (DBS) under the Satellite Instructional Television Experiment (SITE) partnership between NASA and ISRO