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Satellite communications play a vital role in modern life, delivering navigation and GPS, cellular networks, high-speed broadband and Wi-Fi, television and radio to millions of people all over the world.
There are more than 3,000 communication satellites orbiting around the planet, providing the key to military, aerospace and other vital applications by transmitting and relaying information globally from one place to another.
The technology allows access to data and voice communication services across the planet to places where cellular and broadband coverage is unavailable, or patchy network coverage is an issue. So, whether you’re flying at 35,000 feet, travelling across the world’s oceans, or visiting a remote place on land, satellites have got you covered.
On ground level, satellite companies facilitate the technology, infrastructure and solutions for governments, industry, organisations and individuals to use the system efficiently.
What do satellites do?
Thanks to evolutions in technology, satellite communications are creating a more connected planet and providing endless opportunities for innovation such as unmanned aerial vehicles or drones, crop monitoring and autonomous transport to name but a few.
Giant antennas located in space all around the world are used by US space agency NASA to communicate with spacecraft through the Deep Space Network. System operators break commands into digital bits, aim the antenna at the spacecraft and send the commands via radio waves. Some of the commands can take minutes or even hours to reach their destination, because despite their high speed, they have so far to travel.
Of course, satellite communications have capabilities more useful to the public than communicating with spacecraft. They transmit radio waves at the speed of light, which is 186,000 miles per second, every time we send an email using Wi-Fi, listen to the radio, or talk on a mobile phone.
How do satellite communications work?
Satellite communications use the satellites orbiting above the earth, combined with ground stations, to transmit information from one location to another. The process comprises three stages: uplink, transponder and downlink.
For example, the uplink stage includes a live television broadcast, when the broadcaster transmits a signal to the relevant satellite through a user terminal.
The transponder stage occurs when the orbiting satellite receives the signal, boosts its strength and changes its frequency, before relaying it back to the designated ground station back on earth.
During the third and final stage, the downlink, the ground station, or multiple ground stations across the planet, receive the signals.
Ground stations complete the satellite network by providing electronic steered arrays (ERAs) in the shape of flat panels, or circular reflectors, commonly known as dishes, to process the information and deliver it to its destination, normally on fixed points on the ground.
However, advances in technology in recent years have made it easier to receive signals when on the move, leading to the evolution of in-flight Wi-Fi, satellite news gathering, 5G networks and other mobile applications.
While the earth already has a substantial network of ground stations, these are growing continually to keep pace with new technology and the greater demand for satellite communications.
Role of PCBs
Printed circuit boards play a major role in satellite communications, where they need to be exceptionally durable to withstand the harsh and unforgiving conditions of space. They must survive temperature extremes, debris, radiation, zero gravity and low-pressure vacuums.
Without high performance PCBs, satellites wouldn’t be able to function. An integral part of satellite technology, they contribute to almost every aspect of its functionality.
Any problems caused by a short circuit in a satellite can have a massive negative impact on a global scale. This would impact space exploration, the aerospace industry and military operations, as well as worldwide communications.
The PCB has many different roles, containing components such as transceivers and amplifiers for signal processing and communication, which govern how the satellite can receive and send data.
Antenna interfaces must provide a link between the ground stations and antenna which will continue to work, no matter how harsh the environment. Once the satellite has received and processed data, it is stored using memory modules and microprocessors with their own PCBs.
Specific design techniques are required to make smaller PCBs, where the relevant technology must be contained in a tiny space with full functionality. When the satellites operate on higher-frequency bands, certain layouts and materials are needed to prevent signal loss.
PCB design for space conditions
PCBs in space operate in harsh environments and need to meet strict requirements to function correctly, so satellite printed circuit board design must be done with specific structure and materials.
A manufacturer wouldn’t be able to use the same PCB materials as they would for light use in the home. In space, to withstand extreme conditions, high-performance substrates are necessary, such as polyamide or ceramics.
Having said that, copper is used in space, as well as on earth, due to its high conductivity and light weight. Another popular PCB material in space is fibreglass-reinforced epoxy. Gold provides a reliable and durable surface finish, thanks to its excellent conductivity and corrosion-resistance.
A solder mask with high thermal stability is required to protect the PCB from short circuits in cold and hot temperatures.
PCBs used for satellite communications must be as small and lightweight as possible, so every millimetre of space must be filled. The total number of layers will depend on the complexity of the electronic system, but to save space, miniaturisation techniques are used including Microvia and interconnects.
They commonly have dedicated ground planes and power planes to minimise electromagnetic interference and distribute power respectively.
Solder joints need extra strength to withstand vibration and shock, so the components are commonly subject to hermetic sealing to offer a high level of protection in the space vacuum. The PCB must be radiation resistant, so the sensors, microprocessors, memory and power supply need added protection.
Satellites operate continuously for long periods, so all parts are designed for longevity and durability with little maintenance.
Playing a vital role in the connection between satellites and ground control, PCBs host signal communication and processing components, including transceivers and amplifiers. Impacting the receiving and sending of data, if they fail, the satellite will no longer be operational.
Sellectronics’ Space Heritage
Offering a high level of expertise and quality when it comes to PCB assembly and prototyping for satellite communications; we’re particularly involved in the manufacture of PCBS for satellites in Low Earth Orbit – one of the four categories of communication satellites.
LEO satellites orbit closer to earth and are much smaller compared with Geostationary Earth Orbit, Medium Earth Orbit and Highly Elliptical Orbit satellites that orbit at a height of around 160km to 2,000km above the earth, with an orbit time of around 90 minutes.
Requiring a larger constellation of satellites to operate effectively, the LEO orbit is at a relatively low altitude and has low latency and a smaller field of vision than its counterparts. It can relay high levels of data accurately with strong signals at greater speeds.
Due to these benefits, LEO satellites are commonly used for applications such as emergency response, maritime, tourism, industrial Internet of Things, government and tactical networks, telecommunications and mobile 5G broadband.
Sellectronics’ space heritage includes the use of our PCBs in the DMU30 inertial measurement unit, which is used in satellites launched into LEO by the global satellite operator, iQPS.
With uses in outer space, commercial flights and military defence, our aerospace PCBs can stand up to harsh environments and demanding conditions such as radiation, pollutants and high temperatures.
Our manufacturing and assembly processes adhere to the industry leading aerospace standards AS9100D & BS EN ISO 9001 to ensure complete reliability and longevity.