This article highlights the space junk problem, predicts the situation in 2030, and discusses what the missing piece to make sure this doesn't out of hand.
(Image credit: ESA)
From people throwing their litter on the road to factories dumping toxic chemical in rivers and lakes, dealing with waste and junk from human activity has always been a problem. So waste in space is not surprising.
Since Sputnik (1957), humans have been launching satellites into Earth orbit. In the 2010s, the amount of satellites being launched has gone up by more than 7 times compared to the decade before (from UCS satellite database). Majority of this increase is in the ‘low Earth orbit’ – this is typical an orbit height of less than 2000km from sea level.
At these orbital altitudes, satellites and any objects can stay in space for several years to a few hundred years, and become space junk.
So what is this space junk?
Simply put, objects orbiting Earth that cannot control their own trajectory is called space junk (or space debris). It mainly consists of spent rocket boosters from satellite launches, nuts, bolts and other small objects used for staging, deploying solar panels, or other mechanisms, and also dead de-commissioned satellites.
Why dealing with it is important?
As per the lastest figure from the European Space Agency, there are 934,000 objects greater than 1 cm in size, and 128 MILLION smaller than that.
If two objects collide in space, it produces even more debris. In the worst of cases, a small 10g bolt flying at orbital speeds can have as much energy as a fully loaded TukTuk (around 600kg) travelling at 115 kmph!
Dead, non-functioning satellites are by far the biggest contributor to the increasing risk of collisions. A couple of years ago, I made a simple model to estimate the amount of non-functioning satellites in the future if the current rules and regulations are still in place. Here is an updated version for this coming decade (2020 – 2030).
The number of dead satellites will be nearly THREE TIMES MORE than what it is today. Remember - this is only dead satellites and not other smaller objects or launch vehicle stages – not any of the other small objects that are there right now and will be in the next 10 years.
The rate of satellites being launched in to the low Earth orbit environment is way more than those being deorbited.
24/7 weather forecasts. Long term climate monitoring. Agricultural crop yields. Modern fishing. Satellite navigation. Satellite TV. Satellite internet. And so much more that keeps our modern world running depends on space based services directly and indirectly.
Human presence in space is also going to increase. This is an extremely complex problem to solve. Space junk, and more specifically sustainable Earth orbits need to be discussed in the same forums as sustainable environment.
What is being done?
There are several solutions — proposed, in-development, or being tested to try and solve space junk.
Catching debris and removing it — for example with harpoons, nets, or robotic arms, is one solution.
Another is to equip future satellites with de-orbit devices — de-orbit sails or extra propulsion for example. However, this does nothing to actually clean up old junk.
There are several companies, space agencies, universities, and research institutes working on solving this.
This is a very complex issue, and several things are key to solve this problem - from regulatory change to technological change and corporate behaviour change. However, there is one key that is seldom discussed...
...that key: Scalability
In all my conversations with researchers, space lawyers, engineers, and anyone working on this, there are many highly debated questions — for example, “who pays for clearing out all the junk?”, or “should this be like ‘road tax' everyone pays to operate in space?”
Amongst all the debates and panel discussions, I have seldom seen the scalability of solutions being addressed. As part of these discussions, we must also ask:
How affordable can these solutions be at scale? (Low cost is key — you’re essentially developing space garbage collectors, and noone will pay an exorbitant price to get rid of waste)
How fast can we scale it? (Faster = better. At the scale this issue is growing, it needs to be much, much faster)
Just like the ocean, land, and air, space is critical for our modern society - let's make it a part of the wider sustainability discussion.
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If you are an expert in this topic and find any inconsistency, let me know by emailing adit@theaeroengineer.com