Kyoto University and Sumitomo Forestry are building a wooden satellite to make space exploration more sustainable.
Man-made satellites are machines launched into space and orbit Earth or another body in space. They are designed to provide information about Earth’s oceans, land, and air. Satellites can also take pictures of outer space and send TV signals and phone calls around the world. There are currently over 8,000 active satellites in space.
Satellites are typically constructed using diverse materials, ranging from robust aluminum to resilient titanium, chosen for their exceptional strength, lightweight properties, and corrosion resistance. In addition to these metal alloys, plastics also find utility in satellite construction, primarily for non-structural components or as protective coverings.
These materials serve crucial roles in ensuring satellites’ durability, functionality, and longevity in the harsh conditions of outer space. Aluminum and titanium provide the necessary structural integrity to withstand the rigors of launch and the extreme temperature fluctuations encountered in orbit. Meanwhile, plastics offer versatility and insulation properties, safeguarding delicate electronics and sensitive instruments housed within the satellite’s framework. The careful selection and integration of these materials underscore the meticulous engineering required to design and fabricate satellites capable of fulfilling their intended missions in the unforgiving expanse of space.
Satellites can be unsustainable for many reasons. Many satellite materials, such as rare earth metals used in electronics or specialized polymers, rely on scarce natural resources that require mining and processing. The extraction of these resources can lead to resource depletion. The production of satellite materials often requires large amounts of energy, especially for processes like refining metals or manufacturing composite materials. This energy consumption contributes to greenhouse gas emissions and exacerbates climate change.
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Satellite manufacturing processes can generate significant waste, including scrap materials and byproducts from production processes. Moreover, when the satellites reenter Earth, they burn and create small alumni particles that will remain in the upper atmosphere for many years. The risk is that these particulars will end up in our ozone over time, damaging the Earth. There is also a rise in the number of satellites likely to be launched in the coming years, which could amplify these effects.
Satellites are unsustainable due to the improper disposal of these waste materials, which can lead to environmental pollution and harm ecosystems. Finally, satellites have a limited operational lifespan, after which they become defunct or obsolete.
The LignoStella Space Wood Project, led by Kyoto University, is testing a new material that would make space exploration safer and more sustainable. They are testing the possibility of creating wooden satellites.
In 2020, the team tested several types of wood, including Erman’s birch, Japanese cherry, and magnolia bovate. The wooden satellite test samples were tested for more than 290 days at the International Space Station before being returned to Earth earlier this year.
The team found that magnolia wood was the most stable and resistant to cracking. Despite the harsh conditions in outer space, including extreme temperature variations and exposure to cosmic rays and solar particles, magnolia wood has proven to be very resilient. No measurable mass change was found in any of the wooden satellite samples before and after the space experiment.
Another reason for making wooden satellites is that wood would completely burn up when reentering the Earth’s atmosphere and wouldn’t throw harmful substances or debris in the process. Wood can also be used in the design of satellites, whereby its ability to permit the passage of electromagnetic waves enables wooden satellites to embrace a streamlined design, incorporating components such as antennas directly into the satellite.
The Ligno Sat wooden satellite will be launched into space this summer, and if it is successful, it could open up new possibilities for space exploration. There is still a lot of research yet to be done but this a way forward to changing how we use our Earth’s resources on and off our planets. If we could change how we design for space exploration with more biodegradable and sustainable materials, who knows what we can do in the future?
