Geminids meteor shower lights up the sky this time of year. It has been returning for over 150 years. But these days, when you see a shooting star, there is a chance it isn’t a meteor. It may be a piece of our own space garbage incinerating on reentry into Earth’s atmosphere.
Humans have launched thousands of tons of hardware into space for all kinds of purposes, and we started out with some simple solutions for when a space asset completed its useful life. We could leave it where it was, hoping it would eventually de-orbit itself into Earth’s atmosphere, which it often would. Or we could save a little bit of propellant for a final move, either right into the atmosphere for those satellites close to Earth or up to a high “graveyard orbit” for those satellites already much farther from Earth. Those solutions worked well at first, when there were a few, and then tens, and even hundreds of satellites in Earth’s orbit.
Now forecasts anticipate as many as 100,000 satellites in space by 2030, and concern is growing over the impacts of space debris. Some worry about increasing complexity in conducting space missions. To steer clear of other space traffic, spacecraft would have to perform regular evasive maneuvers. This would add cost and time to the design, construction, and ongoing operations of those spacecraft. In anticipation of this high-traffic scenario, various government entities are already making rules for speedier de-orbit of spacecraft at end of life. That accelerated de-orbit solution could make a significant difference in the economic and operational sustainability of space missions as space activity grows in the short term.
But has the pursuit of economic and operational sustainability obscured unintended environmental consequences? Concern is growing over the environmental effects of burning up increasing amounts of metals and other materials in the atmosphere. That practice may prove environmentally unsustainable. So problem-solving entrepreneurs have begun working on how to extend the lives and expand the capabilities of spacecraft. Orbital transfer vehicles, or space tugs, could increase the mobility of existing spacecraft, and satellite servicers could make repairs or provide resources like propellant to advanced spacecraft. Iterating on this practice of life extension and increased mobility for evasive maneuvers could put off end of life, thereby postponing de-orbit, and there are many reasons to field those capabilities.
Those prospects hold promise for sustainability in the medium term, but any environmental consequences would only be delayed rather than averted.