What are the different components in a satellite?

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Sep 28, 2023

According to data from the Union of Concerned Scientists, a startling 6,718 artificial satellites are orbiting Earth, each one a tribute to human ingenuity and technological advancement. From international communication networks to Earth observation and extraterrestrial exploration, these satellites support a wide range of missions and uses. The multiple elements that come together and smoothly orchestrate the actions that let these orbiting objects carry out their missions are explored by satellite technology.

Artificial satellites are the most adaptable and necessary inventions of the modern era. They are made up of many different components, from the satellite bus, which acts as the structural core, to the payload, the specific equipment that defines their purpose, the exact engineering, and cutting-edge technology. These space-borne systems have a wide range of shapes and functions, yet below their outward variety, they all share essential elements that make them functional.

Satellite Bus

A satellite bus houses vital components that guarantee proper functioning, and acts as the satellite's main structural component. It is possible for satellite operators to either modify the construction of the satellite bus to fulfill mission needs or to purchase pre-built bus designs from reputable manufacturers like Boeing or Airbus. Components in a satellite bus are -

  • Power System: The power system is a fundamental component, as satellites require a constant source of power to carry out their functions. Solar panels, which harness energy from the sun, are the primary source for most satellites. These solar panels convert sunlight into electrical power to supply the satellite's systems and charge onboard batteries for use during eclipses or when solar energy is not available. Emerging electric satellites utilize various methods such as electrostatic, electromagnetic, or electrothermal power to accelerate propellants for thrust generation. Additionally, some satellites employ ion propulsion, utilizing xenon gas to achieve propulsion efficiency.
  • Guidance Navigation & Control (GNC): The precise steering and movement of satellites is the focus of the highly developed engineering discipline known as GNC. GNC is a sophisticated field of engineering dedicated to the precise guidance and maneuvering of the satellite. It involves station keeping, which ensures the satellite maintains its intended orbit. GNC also involves pointing adjustments to compensate for disturbances caused by factors such as solar pressure or atmospheric drag. This component is an essential part of satellite functionality since GNC systems rely on numerous sensors, complex algorithms, and precise control mechanisms to carry out these tasks.
  • Antenna: Satellites depend on communication, and antennas are essential for enabling data transmission. Satellites need to upload and download mission-specific data as well as GNC orders, power instructions, and other types of data.  The antenna's capacity for transmitting data is closely correlated with its size, with larger antennas facilitating more effective data transfer. Large antennas are used by broadband satellites to provide smooth data transfer when transmitting high-definition material to Earth. Broadband satellites tasked with streaming high-definition content to Earth employ large antennas to facilitate efficient data transfer.
  • Avionics: The electrical operations of the satellite are managed by avionics systems, assuring uninterrupted functioning. Various spacecraft functions that cannot be directly controlled from a ground station are controlled by these systems. The avionics systems are responsible for managing the satellite's electrical functions, ensuring its continuous operation. These systems control various aspects of the spacecraft that cannot be directly commanded from a ground station.  The onboard computer, an integral avionics component, runs primary flight software responsible for automating satellite functions, including the execution of GNC control algorithms for station keeping, sensor measurement acquisition, and data processing. For station maintenance, sensor measurement acquisition, and data processing, this also includes the application of GNC control algorithms. The autonomy and dependability of the satellite depend heavily on the avionics systems.
  • Payload: The payload constitutes the specialized equipment or instruments designed to execute the satellite's specific mission or function. The composition of the payload varies widely, tailored to the satellite's designated purpose. Payload configurations can include components such as cameras, sensors, antennas, transponders, and other hardware essential for fulfilling the satellite's mission requirements.
  1. Earth Observation Satellite: Payloads for Earth observation satellites encompass hardware and software for cameras or sensors. These components enable the satellite to capture high-resolution images and collect data related to the Earth's surface, facilitating applications such as environmental monitoring and disaster response.
  2. Internet Satellite: Transmitters, receivers, and enormous antennas are often present in the payloads of Internet satellites.  These components enable global internet connectivity, facilitating high-speed data transmission between satellite and ground-based internet users.
  3. Military Satellite: Payloads for military satellites encompass a range of components designed for surveillance, reconnaissance, targeting, and secure communication. These payloads are crucial for military operations and national security.
  4. Space Telescopes: Advanced observational and scientific tools are included with space telescopes like the Hubble and James Webb Space Telescope. These instruments enable astronomers to explore distant celestial objects, study the universe's origins, and collect essential scientific data.
  5. Scientific Satellites: Scientific satellites may carry specialized instruments such as multispectral imagers, infrared or UV sensors, and other scientific sensors. These instruments support conducting detailed Earth mapping, solar system research, and extraterrestrial exploration.
  6. Global Positioning System (GPS) Satellites: GPS satellites feature payloads consisting of radio transmitters and receivers. These components enable the satellite to communicate with ground-based GPS receivers, allowing precise location determination and navigation for a variety of applications, including GPS navigation in cars and smartphones.
  7. TV Provider Satellites: TV service providers run satellites with payloads designed to provide television signals to ground-based receivers such as satellite dishes on customers' properties.   As opposed to bidirectional internet satellites, these payloads are designed for one-way data transmission, simplifying their configuration compared to bidirectional internet satellites.