Understanding which parts of satellites can be acquired individually, or together, is an important early step in mission design. This page explains the core categories of satellite components and subsystems available on the market today.
It also links to various other pages and resources from where you can learn more about the individual satellite components and subsystems, see what is on the market today, and compare options for your mission or design. If you have any questions about any aspect of satellite technology, we’d be more than happy to help – feel free to contact us here.
Navigation
- Platform + payload = satellite
- Satellite payloads
- The satellite bus
- Satellite structure and housing
- Power systems and components
- Guidance Navigation and Control (GNC) equipment
- The satellite avionics system
- Command and Data Handling (C&DH)
Please note that there are various different ways that engineers can design and classify aspects of the ‘system of systems’ that is a satellite, and so some of the categories on this page intentionally overlap with each other. But all these category labels are commonly used across the space industry to define different areas or functions of a satellite.
Platform + payload = satellite
At a basic level, you can think of a simple satellite as having two key parts:
- A platform, or bus, that consists of everything needed to transport, protect, and operate the payload, and
- A payload that carries out the primary function of the satellite’s mission.
The platform is the vehicle and the payload is the passenger.
For many teams, the core innovation of their new satellite design, and the primary value-generating aspect of the overall system, is the payload.
However, the best payload in the world isn’t worth much if it doesn’t get to the right orbit, with all the resources and connectivity it needs in order to work effectively.
Space is a harsh operational environment and only good quality platforms, combined with effective payloads, result in a working satellite.
Satellite payloads
When it comes to primary payloads – there are a variety of different options available on the market today, each carrying out one or more core value generating activities.
Here are some of the most common types:
Imagers – optical and other frequency payloads, such as Earth Observation (EO) cameras in the visible spectrum to take pictures of Earth. Including Synthetic Aperture Radar (SAR) systems, VNIR and SWIR systems.
Communications – where satellite communication is the primary mission objective, such as for telecommunications satellites.
Tracking – satellite-based tracking systems to monitor vehicles and other assets on Earth, such as:
- Ships via Automatic Identification System (AIS) transceivers
- Planes via Automatic Dependent Surveillance–Broadcast (ADS-B) transceivers
- Various targets via or Automatic Packet Reporting System (APRS) technology
Connectivity – internet broadband and Internet of Things (IoT) or Machine to Machine (M2M) connectivity services.
Click here to browse a huge range of commercially-available satellite payloads, across all areas of the market.
The satellite bus
A satellite bus (or satellite platform, the terms are often used interchangeably) will usually the structure and housing of the system, along with various components and subsystems needed to enable different aspects of the mission.
How much in-built functionality is included varies from supplier to supplier, and for different models within one supplier’s portfolio. But all technologies onboard are usually pre-integrated and pre-qualified, making it simple to get up and running with a new bus.
If you need a plug-and-play CubeSat platform for a simple Earth Observation (EO) payload, then you’ll find plenty of options on the market to meet your requirements.
If, instead, you require a high level of customization (perhaps you’re building an advanced microsatellite or relying on a number of deployable components) then there are also modular platforms that can be tailored to your needs, for an additional cost.
And there are also suppliers who can create 100% bespoke systems from scratch, though typically including one or more flight-proven (i.e. TRL9) subsystems.
Click here to view over 100 different satellite platforms from suppliers across the global market
Satellite structure and housing
The satellite structure is the chassis of the system that gives it shape, form, and strength. It defines the spatial limitations and volume of the satellite (such as adhering to the CubeSat standard for example), and provides protection for the internal systems.
A satellite structure can be a simple frame, with or without pre-integrated panels for the walls. This is often called the primary structure. The basic metal panels may be replaced with, or enhanced by, solar panels to collect power in orbit.
The satellite structure needs to ensure it can cope with the thermal expansion and contraction resulting from temperature changes during integration to the launch vehicle (LV), launch itself, deployment into space, and orbit.
The satellite’s internal systems can also produce excess heat during operation which needs to be controlled so that it doesn’t affect performance in certain areas.
Basic thermal regulation will be provided by the satellite structure, but for more powerful regulation of hot spots, technologies such as thermal straps or thermal links are used to create conductive links that transfer energy between hotter and colder interfaces.
Thermal management coatings may also be used, applied to various parts of the satellite.
Heating elements may be required if additional thermal energy is required for certain aspects of the mission.
The satellite structure must also protect the system from radiation in space.
Click here to view over 100 different satellite structures from across the global marketplace.
Power systems and components
The components that provide and manage a system’s power are some of the most important parts of satellites. Without power a satellite can’t do anything once it is deployed – it just becomes another piece of space debris.
A satellite’s power system is made up of the following subsystems and components:
Solar panels – to collect solar energy in orbit. Made from space-grade solar cells and situated on satellite structure panels, and/or as deployable systems that extend while in orbit; using technologies called Solar Array Drive Assemblies (SADAs) or Mechanisms (SADMs).
Batteries – to store the energy until it is used. Modular batteries are manufactured by a range of suppliers around the world, with solutions to fit all satellite form factors.
Electrical Power System (EPS) – to manage and control the distribution of power.
Guidance Navigation and Control (GNC) equipment
The GNC category includes the satellite components and subsystems that make up the Attitude Determination and Control System (ADCS) and those that are used for position determination.
GNC subsystems are crucial satellite engineering components – it is often described as the operational core of a spacecraft and is fundamental to enabling it to carry out the mission objectives.
GNC equipment is also a very mature area of the industry with many flight-proven options on the market.
Attitude
ADCS equipment includes:
- Attitude sensors – that determine the system’s orientation
- Attitude actuators – that change the system’s attitude
- Integrated ADCS – the combine both attitude sensing and actuation capabilities
Position
Positioning components depend on the orbit and mission plans. In Earth’s orbit it is possible to determine position using GPS, but in space more advanced technology is required.
The satellite avionics system
Avionics is a high-level term that refers to most of the main functional elements of the satellite – including the command and data handling system, the payload, and several other aspects. Subsystems classed as avionics are typically electronics systems, rather than mechanical.
The flight software (FSW) is also classified as part of the avionics system, as is the command and data handling (C&DH) system, discussed in the next section.
Command and Data Handling (C&DH)
The C&DH system, commonly known as the satellite’s ‘brain,’ is the set of equipment that can perform several satellite functions, namely:
- Communications interfaces
- The Telemetry and Telecommunications (TT&C) sub-system
- Ground station tracking and communications system
- The payload
- Data storage and on-board software
- The on-board computer (OBC) and payload processors