For the past three years, Amorim Cork Solutions team has worked in the innovation and product development department, with a particular focus on aerospace applications. This article provides an overview of Amorim Cork Solutions, the unique capabilities of cork, and the development of a new bio-based thermal protection system (TPS) for reusable launchers within the SALTO project.
Amorim Cork Solutions: Sustainability and Innovation Through Cork
Harnessing a Natural, Renewable Resource
Amorim Cork Solutions specialises in developing advanced composite core solutions that combine innovation, performance, and sustainability. Our work centers on reusing cork—a 100% natural raw material—to create high-value products for industries ranging from aerospace and mobility to sports surfaces and even toys.
Each product is developed as a strategic response to market needs while upholding our strong commitment to environmental responsibility.
What is Cork and Why Is It Sustainable?
Origins and Harvesting
Cork is the outer bark of the cork oak tree, which grows primarily in the western Mediterranean. Its sustainable character stems from two core factors:
01. Regenerative harvesting – The tree is never cut down. Instead, skilled harvesters remove the outer bark every 9–12 years.
02. Longevity – Cork oaks live for around 200 years, allowing repeated harvests throughout their lifetime.
A Natural Carbon Sink
Cork oak forests sequester significant amounts of CO₂, and the carbon stored in cork products exceeds the emissions generated during harvesting, transport, and manufacturing. This results in a negative carbon footprint, a rare characteristic for engineered materials.
Circular Economy Culture
At Amorim Cork Solutions, we use by-products from wine stopper manufacturing, as well as other materials and by-products from different industries, converting leftover cork into new materials through our iCork Factory, a facility dedicated to innovation, new processing technologies, maturation technologies and prototype development.
Why Cork Works in Aerospace
A Unique Set of Material Properties
Cork’s cellular structure—millions of tiny, sealed, air-filled cells—gives it an exceptional combination of properties valuable for aerospace:
- Low density
- Elasticity and resilience
- Impermeability
- Thermal insulation
- Fire and high-temperature resistance
- Acoustic and vibration damping
Because of these characteristics, cork has been used for decades as a thermal protection system (TPS) material on multiple space missions.
Cork as a Thermal Protection System (TPS)
A TPS shields rockets and spacecraft during the extreme heating conditions of launch and atmospheric re-entry. Cork is particularly suited for this role due to:
Ablative behaviour
Cork absorbs heat, undergoes controlled thermal decomposition (pyrolysis), and forms a char layer that protects the underlying structure.
Thermal insulation
Even under high heat loads, cork maintains low thermal conductivity.
Low mass
Weight is a critical factor in launch systems, and cork provides protection without penalty.
Amorim Cork Solutions has a long heritage in space, with materials such as P50 used from the 1960s to today across multiple missions.
Developing a Bio-Based TPS for SALTO
Project Objective
Within SALTO project, Amorim Cork Solutions aims to develop an innovative, low-cost, fully bio-sourced thermal protection material. This new TPS must be compatible with an easy-to-replace tile system being developed by partner ID Concepts, enabling efficient refurbishment for reusable rockets.
Currently, no validated models combine cork-based TPS materials with quick-replacement systems for reusability—making this effort a significant step forward.
Key Challenges
The new TPS material must be:
- 100% bio-based
- Easy to apply and easy to remove
- Ablative and insulating under extreme thermal loads
- Lightweight and mechanically suitable
- Compatible with industrial-scale production
Development Process
The material development follows four iterative stages:
01. Formulation Design
02. Production
03. Characterisation
04. Industrialisation
If a formulation fails at any stage, the process loops back to redesign.
01. Formulation Design
This phase focuses on defining performance targets:
Thermal Properties
- Ablative performance
- Thermal insulation
- Char layer integrity (crack depth and distribution)
Mechanical Properties
- Strength
- Density
- Structural stability
Resin and Additive Selection
Resins are evaluated for:
- Bio-content
- Fire behaviour
- Processing and curing requirements
Additives are assessed for:
- Fire performance
- Environmental impact
- Industrial feasibility
The design-of-experiments approach ensures that each material component contributes constructively to the final performance.
02. Production of Formulations
The process involves:
- Mixing cork granules in a vertical mixer
- Adding resin and additives under controlled temperature and speed
- Moulding and curing the material in an oven
- Producing lab-scale blocks, later cut into sheets or test specimens
03. Characterisation and Testing
A wide range of material properties are evaluated, including:
- Density
- Tensile strength
- Compressibility
- Thermal conductivity
- Specific heat
- Thermal expansion
External laboratories conduct key thermal tests such as cone calorimetry, exposing samples to 75 kW/m² (≈800°C) for four minutes. This test helps evaluate:
- Crack formation
- Char layer strength
- Structural integrity under heat
The formulation with the best char performance advanced to industrialisation.
04. Industrialisation
Industrial-scale blocks were successfully produced, confirming strong manufacturability and establishing an ITRL level for production readiness.
Validation in Relevant Environments
To validate performance for reusable launchers, TPS samples are undergoing advanced testing at DLR Cologne, including:
- L2K and L3K high-temperature, high-speed airflow tests
- VMK combined system testing (TPS material + tile system)
These experiments simulate the harsh conditions of re-entry and support the overall qualification of the bio-based TPS.
Amorim Cork Solutions is advancing a breakthrough bio-based thermal protection system tailored for reusable launchers—combining the sustainability and versatility of cork with the stringent performance demands of aerospace applications. With ongoing environmental testing and promising industrialisation results, the material has reached a medium technology readiness level and continues progressing toward full qualification.
This work showcases how natural materials, when coupled with scientific innovation, can deliver high-value solutions for the future of space transportation.