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Close to 9,000 satellites have been launched from over 40 countries since the Soviet Union launched the first satellite, Sputnik, on October 4, 1957. Once used in military reconnaissance missions, satellites are now commonplace and vital to how we see everyday life. How do you think we enjoy live broadcasts of our favorite sporting events, get ready for rain or shine with weather forecasts or even dig into the past to see hidden ancient towns that have been buried thousands of years?
The number of satellites are increasing; an average of 990 satellites are expected to be launched every year from 2018-2028. That is a total of 9,900 by 2028, up from 2,300 satellites launched during the last decade, a four times increase, says Euroconsult in its 2019 edition of “Satellites to be Built & Launched.”
Emerging companies like SpaceX, OneWeb, Telesat, and Amazon’s Project Kuiper say they expect to launch close to 46,000 satellites in the next few years. As they, and traditional manufacturers, continue to innovate, the satellite industry and their designs have been changing as well. As a trusted supplier of sealing and polymer solutions in the space industry, Saint-Gobain Seals has also adapted their material solutions to be just as innovative in order to meet these evolving needs.
Within the satellite industry, the trend has been moving toward lower orbits and smaller satellites. In 2018, low earth satellites (LEOs) comprised about 51% of worldwide launches, and for 2019, they are estimated to increase to over 54%. These smaller, lighter weight and lower orbiting satellites offer the ability to provide business services and reliable, high-speed internet access and connectivity in even the most remote locations where laying fiber-optic cable may not be feasible. Global communications are becoming stronger with this growing technology!
Thanks to private launch vehicle services, the cost to launch a satellite has decreased dramatically in the last decade, going from more than $80,000 USD per kilogram at Space Shuttle time to approximately $1,000 USD per kilogram now. This reduced cost combined with technology that allows for launching simultaneously multiple payloads, made the current concept of small satellites and constellations both technically and commercially viable. As a result, the need for more satellites opens the market to many newcomers who are often agile start-ups competing with established satellite manufacturers, thus stimulating innovation in an otherwise very conservative landscape.
The Trajectory of Advanced Polymer Solutions in Satellite Systems
Two trends emerging from this new landscape are encouraging the move to advanced polymers.
- More compact satellites require smaller, lighter parts: The need for size and weight savings with LEOs has changed the mindset on materials and design. Smaller, more compact, lighter-weight LEO satellites are also often more flexible in design, frequently making polymers a good fit for parts.
- Newcomers, as well as traditional developers, are looking to innovate: This includes looking at ways to more tightly link satellite software and hardware to better gather and transmit information from space to earth, which leads to using advanced materials in systems to gain a competitive edge. And it often includes looking at material solutions that are lighter-weight, longer-wearing, and/or chemically compatible.
Advanced polymers offer a high mechanical strength and low weight. In many instances, they can be a good alternative to metals. Specific benefits of advanced polymers in LEO and other satellite design include:
- Chemical compatibility with hypergolic fluids that are most often used in satellite thrusters and propulsion systems
- Low outgassing and radiation resistance
- Long lifetime of ten to fifteen years required by GEO satellites
- Electric and thermal insulation capabilities
- Capability to withstand vacuum
- A strong existing pedigree for satellite applications and within the space industry in general
Communicating The Many Uses For Polymer Seals & Components in Satellite Systems
How are these advanced polymers specifically being used in satellite applications? The following are five emerging applications.
- In chemical propulsion systems: OmniSeal® spring-energized seals are often used on different types of valves and tanks. OmniSeal® polymer seals can be manufactured from a variety of PTFE and PTFE-blended sealing materials known for withstanding hostile environments and demanding conditions where elastomer seals are not an option.
- In solar array panel deployment systems: Rulon® blended PTFE-filled materials offer a low coefficient of friction on microsatellite solar panel arrays as they fold in launch and expand in orbit. Flight-proven Rulon® J material is an ideal solution for this application as it has one of the lowest coefficients of friction among commercially available blended PTFE materials, offers low outgassing and weight and, can be machined to a tight precision.
- In electro-optic devices: For surveillance, reconnaissance, and earth observation missions, OmniSeal® spring-energized seals protect electronics in plexiglass camera systems from outside environments (more than 30% of satellites launched have this function on board). OmniSeal® seals, with proven applications on aircraft, helicopters and drones, help ensure the system is functioning properly over its lifetime.
- In structural & TRIBO components: Rulon®, Meldin® thermoplastics, Meldin® 7000 high-performance polyimides, and Saint-Gobain HyComp advanced composites replace ceramics, aluminum and other metals as a lighter-weight alternative to connect moving components. Depending on requirements, a variety of these materials from Saint-Gobain Seals can be used to integrate structural connectors, with tribological function (such as with bearings and bushings). In addition to their ability to reduce weight, Rulon®, Meldin®, and HyComp advanced composite materials offer good mechanical properties, low friction, self-lubrication and low outgassing.
- In hall effect thrusters and electric propulsion systems: Many companies are moving to electrical propulsion and xenon gas as satellites become smaller. OmniSeal® spring-energized seals can replace elastomers to offer a tighter seal.
While advanced polymers can offer numerous advantages, metal seals, such as those from Saint-Gobain ASE and HTMS, may be a better alternative in some instances to address the most stringent leakage requirements. When size and weight are less of a factor, and protection of key electronic systems such as altitude or system sensors becomes the priority, metal seals may be preferred since they can meet very tight leakage requirements. Similar tight requirements can also be found inside calibration instruments as can be seen in weather satellites. Other examples in which metal seals may be used include:
- Laser systems
- Primary and secondary power supply systems
- Attitude heading reference systems (gyroscopes)
- Speed, altitude and acceleration measurement systems
- Night-vision devices
With Saint-Gobain Seals’ acquisition of companies with metal sealing expertise and technology, they can offer both polymer and metal sealing solutions, which has expanded their product portfolio as well as broadened their customer base in the space industry. They have been supporting customers for over 60 years in the space industry in missions to the moon, Mars and even further. Within Earth’s atmosphere, they are working closely with key satellite manufacturers, the space companies that are seeking to advance them, and rocket builders that launch them to help innovate satellite design and performance to advance the way we all live and communicate.
In LEO or deep space, contact us to explore how we can help you with your critical space application. Have some time for a good read? Check out our white paper on “Important & Often Overlooked Aspects For Polymer & Metal Seal Selection In Cryogenic Space Applications.”