Ever since I started dealing with active space debris removal, two problems have become very clear to me. One is very much known and discussed among the space industry, which is the “who’s going to pay for it?” problem. There is no proper answer yet, but that’s a question for another article.
The other problem is much more painful, to my taste, and more elusive, rooted in the fact that the only solution we currently use to dispose of old spacecraft is deorbiting them into the atmosphere, where they disintegrate and seemingly vanish. We practice this method of disposal successfully, in most cases, since the beginning of the space age. But the truth is that this is a terrible solution, and it’s definitely not sustainable.
Let’s take a step backwards, to establish some basic facts:
First, orbital debris is a real and imminent threat, especially in low Earth orbit. No arguing about that. It’s threatening humanity’s operational assets in space, and it’s threatening the lives of astronauts currently in space. Debris can be derelict satellites, used rocket stages, or parts and pieces of spacecraft of various sizes. Given enough time, debris in Low Earth Orbit lose altitude, and naturally clear themselves out of orbit. But for some debris, especially the large ones and the high ones, enough time means years and even decades, and with the rising frequency of launches, we can’t wait that long.
That brings in a second fact. The frequency of launching new satellites increases exponentially, as supply’s rushing to keep up with the growing demand. But when the lifespan of a satellite is usually no more than a few years, then in the long run we continue adding space debris, without a proper solution for orbital congestion.
The third fact is that deorbiting debris is a terrible solution. Active debris removal typically involves dedicated missions to capture debris and bring them into the Earth’s atmosphere. However, this practice pollutes the atmosphere with metals and other potentially harmful materials. Some debris don’t evaporate completely by the atmosphere and become impact hazards.
Additionally, destroying a satellite that was very expensive to design, build, test, and launch is a waste, as it could potentially be reused, recycled, or refurbished in orbit. Doing that would transform space debris from hazardous waste into valuable space resources. Manufacturing satellites in space from components and materials harvested from space debris would reduce launch needs and leverage space-qualified materials which already exist in orbit.
However, the required recycling technologies are challenging even on Earth, or at least too expensive to deploy. Even if we find applicable recycling solutions for space, it makes sense to implement them for Earth first. So, while I believe these technologies are the perfect solution for space debris, their deployment in space seems far off.
How can we bridge this temporal gap between the current crisis of space debris, and the future where space recycling becomes a reality?
In my opinion, the best solution is to aggregate space debris in one or several orbital places, where they could be maintained for a long time and easily tracked. Such storage depots may also disassemble, sort, and prepare the stored debris for future advanced processing.
This solution would have two main benefits: First, storing debris in orbit would mitigate the deorbiting hazards mentioned above. Second, future processing facilities would have a convenient organized source of materials and parts to “mine” from, without the need to chase and gather them from their original orbits. In fact, having these facilities in accessible orbits could enable the commercial In-Orbit Space Manufacturing industry.
I think that this solution can be established on a small scale in a few years, based on technologies that were already demonstrated in space, and can be used as a platform for circular economy in space.
In the next articles I will elaborate on the challenges and potential solutions for creating and operating this orbital facility.
Notes:
I purposefully excluded GEO satellites from this article. While there’s a similar problem with defunct satellites in geostationary orbit, and the graveyard orbit solution isn’t sustainable, I focused on LEO solution for simplicity. I may explore other orbital environments in future articles.
In-Orbit Servicing presents a fascinating array of legal challenges. If you find that interesting, I may delve into that topic in a future article.