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StatusCompleted
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Status date2025-03-25
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Activity Code5C.411
This project covered technology assessment and development of lead free assembly technologies for the space environment. This includes solder selection, material properties, conditions for higher temperature reflow, fatigue characteristics, failure modes and adaptation of assembly techniques used for space hardware.
Outputs of these activities are made available for the future evolution of the ECSS-Q-ST-70-61C standard or for dedicated standard for lead free assembly technologies.
The objective of the activities are to develop techniques and technologies enabling reliable lead-free assemblies of RF and digital circuit boards as needed in satcom payloads. An Engineering Model representing sub-system elements for future constellations and geostationary commercial applications were manufactured and tested.
Targeted Improvements were enabling the use of lead-free commercial EEE components for space application not established today.
Regulatory pressures, such as RoHS and REACH, necessitate the adoption of lead-free materials, yet these materials often present reliability issues, including higher reflow temperatures that can compromise PCB integrity and increased risks of tin whisker formation. The selection process for the key candidates during the literature review was therefore crucial. The lack of established inspection methods for lead-free solder joints further complicates the process.
Additionally, achieving the required Technology Readiness Level (TRL) was key, but further testing and optimization are necessary to reach higher TRL Levels.
The lead-free soldering technology offers industrialization and sustainability within the space industry. By adhering to recognized standards like RoHS and REACH, our solder candidate facilitates compliance and eases the transition from traditional lead-based materials to lead-free processes.
Utilizing commercially available materials enhances market stability, ensuring a reliable supply chain less vulnerable to geopolitical disruptions that can affect specialized alternatives. Our focus on partnering with European suppliers further mitigates risks related to international trade, simplifying logistics and improving traceability, and also strengthens the competitiveness of the European space sector.
The lead-free solder alloys, proven through rigorous testing, meet the demanding reliability requirements of space missions, addressing key challenges such as shock resistance and tin whisker formation.
The selected Sn-Ag-Cu-Bi-Sb (Innolot) alloy has shown exceptional performance under testing conditions, achieving high creep strength and reliability, vital for the harsh environments of space missions. Its superior thermal cycling durability, retaining over 75% shear strength after 3000 cycles.
Components of this solution include specialized solder materials designed to mitigate common lead-free challenges, such as tin whiskers and elevated reflow temperatures. Innovations like conformal coatings and underfill materials provide additional protection against tin whiskers and elevated reflow temperature, ensuring long-term reliability.
By adopting these advanced lead-free technologies, the space sector can enhance reliability while remaining compliant with environmental regulations, paving the way for sustainable and resilient electronic systems.
The project milestones were structured as following:
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MS 01: Technical baseline Selection Review
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Phase 1: Finalised Technical Specification
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Phase 2: Selected Technical Baseline
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MS 02: Technology Review
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Phase 3: Verified Detailed Design
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MS 03: EM TRR
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Phase 4: Implementation and Verification Plan
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MS 04: Final Review
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Phase 5: Verified Deliverable Items and Compliance Statement
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Phase 6: Technology Assessment and Development Plan • MS 05: Final Presentation
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- Plan • MS 05: Final Presentation
The project has been completed successfully by providing the necessary proof that the selected solder candidate has reached the targeted TRL 5/6.
