Flex PCBs in Satellite Applications: Lighter Than the Clouds
We are witnessing intensified race among various space agencies for supremacy over the skies for the past few years. As per reports by the United Nations Office for Outer Space Affairs (UNOOSA), more than 4,500 artificial satellites are orbiting the earth with an increase of 4.87% compared to the previous years. Additionally, the increasing interest for flexible PCBs in satellite applications is attributed to the longer lifecycle and the increased flexibility. The viability of flex PCBs for satellite applications is dependent on the capability of the PCB design to operate without fault anywhere up to 10 years.
This has led to intensified race on the ground as well with several PCB manufacturers flexing their muscles in developing high-end PCBs. The electronic equipment needs to withstand harsh environmental conditions, and maintain performance in terms of quality and reliability in space applications. Satellite technology was considered an elite area a few years back. However, the rising footprint of comparatively smaller players in the global landscape will likely increase competition on the ground.
The development of flex PCBs for satellite application has gathered significant interest among several space agencies. The numerous benefits of flex technology are the primary reasons that drive industry players towards the adoption of flexible PCBs. It is evident that the design and development of space-based commercial satellite products are given primary importance in comparison with other electronics and PCBs.
Special attention is given to flex PCB design in order to meet the quality and reliability in higher frequency applications. Manufacturers need to ensure the design of flex printed circuit boards follows certain mandates in high-frequency applications.
Complexity Associated with Commercial Satellite Elements
Typically, satellite systems consist of three main circuitries, which include satellite, receiver, and transmitter. Communication between a satellite and transmitter is referred to as uplink, while communication from receiver to satellite is termed as the downlink. Increasingly, satellites are used for disaster risk management, weather forecasting, remote sensing, geo-positioning, and navigation. Other application of satellite includes television and telecommunication and emergency response monitoring. Electronic components within these circuitries are set to cover highly specific wavelength ranges. These wavelength ranges are within the electromagnetic spectrum. Captured data from satellite involves images, atmospheric sounding, communication, geo-positioning, and navigation.
The gathered information is transferred over longer distances, which is not possible without ground-based systems that heavily relies on line-of-sight transmission. Figuratively, satellites are treated as a is used to gather and process information, imagery, and data from the earth, space or other satellites. For commercial satellite systems, the satellite itself serves as a relay station that allows for data transmission over large distances that would not be possible for ground-based communications systems relying on line-of-sight transmission. Commercial satellite systems are divided into three major types based out of the location, ground equipment and different service on offer.
Types of Satellites and PCB Requirements
Fixed Satellite Service (FSS), Mobile Satellite Service (MSS), and Broadcast Satellite Service (BSS) are three satellite systems that are largely adopted. The Fixed Satellite Service (FSS) uses a fixed receiving stations, which supplies to the end-user. The common application of Fixed Satellite Service (FSS) includes cable TV and internet relay stations. Mobile Satellite Service (MSS) deals with mobile ground systems and mobile phones. These services are also used for communication among ship vessels and fleet vehicles. Broadcast Satellite Service (BSS) broadcasts TV and radio signals directly to users. For instance, Dish Network is used for broadcasting TV channels to subscribers. Thus, it becomes critical for manufacturers to identify challenges and requirements while designing PCBs as per the required applications.
Key Factors for Flex PCB Design
Important Factors that need major attention during Flex PCBs design include:
- Temperature variation – From -100°C to greater than 120°C.
- Sustaining Orbital Collisions.
- Hard vacuum –limiting outgassing from materials.
- Ultraviolet (UV) radiation.
- Ionizing radiation.
It is highly critical to overcoming such challenges at the same time modernize circuitry in order to reduce the space. Commercial satellite components need to be capable of withstanding the harsh conditions during launch and long-term orbits. Flex PCBs manufacturers understand and comprehend design changes accordingly.
Which Aerospace Industry Standards Apply to PCB Development?
Additionally, the number of space agencies are implementing their own standards for developing commercial satellite products. These standards are specifically developed to guide the flex PCB design and development process. Also, these standards help to maintain the quality and reliability of flex PCBs boards. These standards ensure a proper mechanism for failsafe services like the redesign, replacement or recall. Space agencies are currently implementing strategic steps that help to incorporate a safeguard design and high-end development process. This will further prevent contingencies during real-time scenarios.
Some of the common standards that are followed include:
AS 91000 Standard: – Several international organizations that include the Aerospace Technical Committee of the International Organization for Standardization (ISO), the European Association of Aerospace Industries (AECMA), and the American Aerospace Quality Group (AAQG) have developed and redesigned the AS9100 standard for the aerospace industry.
The IPC, NADCAP, the DoD and, the European Space Agency (ESA) Standards: Above mentioned space agencies have developed their own PCB standards or audit checklists for evaluating manufacturer capability. These space agencies closely monitor suppliers that have previously demonstrated compliance in accordance with the standards. These suppliers have to meet and maintain the minimum audit criteria. Several PCB suppliers are complying with the following technical standards to ensure the proper functioning of these PCBs.
MIL-STD-55110: These standards are implemented for Printed Wiring Board, Rigid, General Specification.
MIL-PRF-31032: These standards are placed for the Printed Circuit Board/Printed Wiring Board.
ECSS-Q-ST-70-10C: These standards are mentioned for Space Product Assurance and to measure the qualification of printed circuits boards.
And many more to follow.
Materials in Satellite PCBs
Development of ceramic, hydrocarbon, thermoset polymer composites by Rogers Co., and Isola, Inc., have allowed manufacturers to develop highly reliable satellite PCBs. Most of these materials have dielectric constants (Dk values) from 3.27 to 12.85 in the z-axis. These materials are expected to exhibit a particular set of characteristics. These materials are suited for the challenging operating conditions of orbiting satellites.
Low outgassing is considered one of the major parameters that need to consider before selecting PCB material. Outgassing is the release of gas trapped within a solid, such as a PCB material. Outgassing is the release of gas trapped within a solid, such as a PCB material. Once released, the gas can condense on different surfaces within a satellite, potentially causing problems with some circuits and subsystems.
Upcoming Prospects for Satellite PCBs Across the Globe
The development of high-end flex PCBs has become a priority for PCBs suppliers due to mission criticality for satellite applications. Increasing research and development activities are predicted to foster industry growth over the coming years. These satellite PCBs are put through a series of tests to ensure their consistent performance. The increasing number of private space agencies to amplify growth opportunities for PCB suppliers in the near future.
The criticality associated with flex PCB design during a satellite application leaves no room for error during the development process. Additionally, it is important to test and verify the proper working of the satellite before the lift-off. Satellite technology is responsible for making our life easy and less complicated. It is difficult to imagine our modern lifestyle without it. It is critical to implement a thorough, exhaustive and conclusive process to make it happen.
So, stay tuned as the battle for skies will intensify…. We do wonder what Thor might be thinking about it…
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