What Sustainable Engineering Practices are Used in Aerospace?
As with many industries, aerospace has been intensifying efforts to improve sustainability and reduce its environmental impact.
Air travel relies heavily on fossil fuels, and aircraft manufacturing consumes massive amounts of energy and materials. Here are some ways the industry is striving for more sustainable practices.
Advanced materials
The use of advanced materials, such as aluminum alloys and titanium alloys, can reduce aircraft weight and improve efficiency compared to steel and other traditional materials. Composite materials made from carbon fibers, bio-based materials and polymers offer similar advantages, as well as high strength-to-weight ratios and resistance to fatigue and corrosion. Recycled materials — both metallic and non-metallic — can conserve resources and reduce waste.
Sustainable fuels
Sustainable aviation fuels (SAF) from renewable sources such as biomass and repurposed waste materials can reduce reliance on fossil fuels and reduce CO2 emissions. The International Air Transport Association (IATA) estimates that SAF could contribute approximately 65% of the reduction in emissions needed by aviation to reach net-zero CO2 emissions by 2050, a commitment agreed to by IATA member airlines in 2021. Hydrogen fuel cells (HFC) and hydrogen combustion engines are also being researched as alternatives.
Advanced propulsion systems
Electric and hybrid-electric propulsion systems can reduce reliance on fossil fuels and reduce CO2 emissions. They also reduce noise when compared with conventional aircraft.
Electric propulsion systems generate electricity via onboard energy storage systems such as batteries and use electric motors to drive propellers or turbines. Due to battery charging requirements and related trip-range limitations, early applications of electric propulsion systems have been focused on shorter distances (e.g., 100 miles) to deliver freight and feed passengers into larger airports. The National Aeronautics and Space Administration (NASA) predicts that electrified aircraft propulsion (EAP) technologies will be implemented in commercial aircraft by 2035.
Hybrid systems use a combination of electric motors and internal combustion engines to propel aircraft, offering increased flight ranges compared to pure electric aircraft. The two energy sources may work in parallel or series. Turboelectric systems use gas turbines to generate electricity for electric motors.
Solar-powered aircraft use solar panels to capture energy and batteries or HFC to store the energy. While conventional passenger or cargo applications have not yet been adopted due to power limitations, solar-powered uncrewed aerial vehicles (UAVs) have been used for telecommunications, imagery and other applications.
Electric propulsion, in conjunction with vertical take-off and landing (VTOL) technology, is being considered to power aircraft that can take off and land vertically without a runway. These aircraft could be used for applications such as on-demand air taxi services, regional mobility and freight delivery.
Digital design and engineering technologies
Advanced digital technologies have enabled engineers and other designers to work more efficiently, optimize designs and improve aircraft characteristics, such as aerodynamics and fuel efficiency. Computer-aided design, once considered state-of-the art, has advanced and been joined by other technologies, such as digital twins — digital replicas of physical objects such as manufactured products or facilities. Digital twins supplement detailed 3D models with a wealth of metadata and other information to help engineers and manufacturing teams improve designs and facility operations and maintenance (O&M).
Computer-based simulation enables systems and components to be modeled and analyzed in 3D environments without building full-scale prototypes. These simulations aid design optimization for both aerospace products and manufacturing facilities, helping engineers produce more efficient designs and owners determine when to replace or maintain equipment. Specific types of simulation, such as hardware-in-the-loop (HIL) testing, simulate real-world conditions by replacing a physical system with a virtual representation of that system.
Other technologies, such as virtual reality (VR), augmented reality (AR) and extended reality (XR), are also finding new applications in aerospace. These technologies enable immersive experiences that help teams walk through 3D designs interactively, improving communication and aiding decision-making processes.
Automation can be used to improve efficiency in both design and manufacturing processes. By reducing repetitive steps, engineers, technicians and other professionals can increase productivity and improve quality.
Artificial intelligence, which is impacting all aspects of daily life, is advancing in aerospace as well. Engineers are using AI to make predictions, recommendations, and decisions much as humans would, given similar objectives and a relevant knowledge base. AI tools offer conversational interfaces that can streamline analytical processes, enabling engineers to focus on more critical thinking and creative designs.
Improved manufacturing processes
Advanced manufacturing processes such as 3D printing (additive manufacturing) can produce custom products with less energy and waste when compared with conventional manufacturing. Lean manufacturing can reduce waste by streamlining production and increasing efficiency. Other energy-efficient processes, such as variable-speed motors, computer numeric control (CNC) tools and other advanced machinery, can also reduce energy consumption.
Manufacturing facilities can also use renewable energy sources, similar to aircraft, to reduce emissions and energy consumption. Solar, wind and bio-based fuels can be used to power manufacturing plants, reducing the carbon footprint of the aerospace industry. Manufacturing plants can also reduce CO2 emissions through technologies such as particulate filters and catalytic converters. Low-emission coatings and paints reduce the release of volatile organic compounds (VOCs) into the atmosphere.
More efficient use of natural resources can also improve sustainability. Water usage can be reduced with more water-efficient processes and equipment. Stormwater management practices can reduce pollution from surface runoff and manufacturing processes. Recycling of water can be introduced to reuse non-potable water. Recycling and reusing other materials, such as metals, wood, paper and plastic can reduce waste and resource consumption.
Optimized airport and flight operations
Optimized flight paths and air traffic management can improve efficiency, reducing fuel consumption and emissions. Airlines and airport operators can use advanced analytics and machine learning to improve efficiency. Aircraft adjustments such as engine modifications for improved aerodynamics can improve combustion and airflow, also reducing consumption and emissions.
Airport infrastructure can be designed and constructed with more sustainable materials and processes. As with manufacturing facilities, airports can use renewable energy sources, implement water management practices, and incorporate more green building materials to reduce CO2 emissions. Public transportation for passengers and airport workers can reduce fuel consumption and emissions.
Lifecycle assessments
Lifecycle assessments (LCA) evaluate the environmental impact aircraft and their components across their entire lifecycles, identifying potential areas of sustainability improvement. This can include everything from raw material acquisition through design and manufacturing to operation and end-of-life disposal.
The aerospace industry has numerous opportunities to improve sustainability. Engineers and other professionals can use a combination of new techniques and materials, as well as improvements to conventional processes, to help guide these efforts.
Written by: Andrew G. Row, Author, for Engineering.com.