Consider a car on the highway, with the driver slumped behind the wheel, leg still on the accelerator, as more cars join the same lane. We currently decommission many spacecraft by simply leaving them in orbit.
Space exploration has become a megatrend. According to the European Space Agency’s Space Environment Report, we launched over 1200 satellites last year, which is three times the number we launched two years ago. SpaceX alone intends to launch tens of thousands of additional satellites in the coming years.
However, increased space utilization comes at a cost.
The rock that can shatter your windshield is known as space debris.
Currently, over 8000 tons of space debris orbit the Earth. Size doesn’t matter in space; both large and small debris can be lethal. A paint flake that gouged out a chip from the window of the International Space Station, like the bus-sized zombie satellite Envisat, poses a threat to spacecraft. This is due to the fact that all space debris, large or small, travels at a velocity of 7.5 km/s. In other words, a gram-sized particle in space has the same momentum as a fist-sized rock smashing through your windshield on the highway.
You may believe that there is plenty of room in space and that the increasing number of new launches isn’t a concern. However, as orbits become more crowded, the risk of collisions rises, increasing the number of debris particles. This can result in the Kessler Syndrome, in which a dense cloud of tiny particles eventually surrounds the Earth, preventing all future spaceflight.
Clearly, we must ensure that space remains usable and that future generations can fly in space. But how can we make space more sustainable? Finding a balance between several aspects of a whole so that the whole is available in the future is what sustainability is all about. In space, the whole consists primarily of the physical environment, satellites, and satellite data users.
We must begin to consider the physical environment of space, such as our orbits, as an asset: something we value, rather than a shared resource.
Caring about only one aspect jeopardizes the overall survival. We currently prioritize economic returns, so we flood space with tens of thousands of low-cost satellites. We value data, so we launch expensive, carefully constructed satellites into strategic orbits. However, we do not place enough emphasis on the physical environment. As a result, we have a poor understanding of space physics.
Maintaining the space highway
Space physics is critical to the long-term use of space and the future of human spaceflight. Space conditions determine how long satellites remain operational, and sometimes even when they return to Earth. Starlink lost 40 satellites in February 2022 due to a phenomenon known as Joule heating. This serves as a reminder of why we should continue to study space physics. The phenomenon of Joule heating is well understood, but current quantitative understanding is so limited that it is impossible to predict when and where it will occur. The same can be said for a slew of other potentially disastrous space weather effects on modern society. We don’t know when ionospheric currents will cut our power or when the ionosphere will swallow our aircraft radio transmissions, making polar flight impossible.
We must begin to consider the physical environment of space, such as our orbits, as an asset: something we value, rather than a common-pool resource to be recklessly exploited. Large spacecraft should not be allowed to become zombies; instead, they should be safely de-orbited before the mission ends. Small satellites should not be left in orbit indefinitely. We don’t build a new car every time one breaks; instead, we send it in for service. Likewise, we require servicing technologies that allow operational spacecraft to continue their missions. We also require technologies to clean up existing debris and prevent new debris from being launched at an increasing rate. We also need to launch satellites for reasons other than economic returns or data needs. We need to improve our understanding of space physics.
Durable spacecraft for long-term space exploration
Frustrated with waiting for space agencies to understand why measuring near-Earth space with spacecraft is critical, I founded the Finnish Centre of Excellence in Research of Sustainable Space, which builds and launches nanosatellites. Our goal is to keep new debris from accumulating. In the harsh space environment, all spacecraft will eventually become unusable. Before they do, they should be destroyed so that they do not endanger other spacecraft. The Centre of Excellence researches near-Earth space physics and creates cutting-edge de-orbiting technologies. Anyone who wants to build a long-lasting spacecraft can use the open-source results. On 1 June 2022, the Centre will launch its first CubeSat demonstrating resilient design and de-orbiting technology, with the goal of leaving a lasting impact on the sustainable use of space and orbit safety.
We opened new doors over 50 years ago with the first human spaceflight, unlocking the use of space for the benefit of all humanity. We must ensure that this window of opportunity and advancement does not close for future generations. As we continue to explore and commercialize space, we must reconsider our current strategy and adopt a more sustainable approach to space use in order to improve the well-being of people all over the world.