The Forearm of God as the Future of Space Debris Removal
My thoughts on what active debris removal will have to be, in order for us to not get laughed at by our children
So I’m very concerned with the space debris problem. Exceedingly concerned. So much so that it’s actually the main reason I got into the space industry in the first place. I mean I did like space and everything, but the catalyst for actually trying to make a living doing this was my friend (and co-founder) coming to me and telling me about Kessler Syndrome.
Hence, I’ve done a lot of thinking about space debris.
The other night, we were having a chat with a VC about our tech, and like many others, he thought that building de-orbit devices is a bit of a non-starter. Well, for now at least. I’m pretty confident that one day soon the FCC will impose stricter debris mitigation standards, maybe even bumping it up to proper regulation, and that’ll be a real turning point in this entire battle.
Well, either that or we get crushed by the boot of history because space becomes hazardous and unusable. Now, I’m not saying that space junk is the Great Filter in action, but if I was, I would also say that if we fail this, it’s both tragic and hilariously, absolutely, 100% our fault.
Anyway that VC was right, as are pretty much all the others. Nobody’s going to pay for de-orbit tech unless you have a gun pointed at their wallets. Which got me thinking about what the future of active debris removal (ADR) will look like. I’ve got a couple of ideas.
[EDIT because I’m bad at clarifying things: We don’t build de-orbit tech, we build propellantless propulsion. We’d like to though, someday.]
Excising Tedium
So consider the average ‘game-changing’ innovation, from industrialisation to Uber. I’d say one of the major traits they all have in common is that they get rid of tedium. Instead of having to call each cab company one by one, you just open an app and it does all the stuff for you. It’s just plain convenient. The fastest route is a straight line, etcetera.
Now consider a bag of rice that’s been spilled on the counter. You could pick up each individual grain with your fingers (or a pair of chopsticks, as I once did at a party as part of a game). Or you could sweep the whole lot off of the counter and back into the bag with your forearm, all at one go.
The current shape of space debris removal (distinct from mitigation, which I’ll kind of address but only obliquely), I’d say, has more in common with the first technique of using your fingers. Without naming any names, the presently available options include some variation of pushing debris out of orbit with other satellites. An alternative solution involves using an orbital tug, which is better in my opinion but still fails to address the fundamental issue of tedium - of having to handle each problem individually.
This reminds me of a problem in mission architecture that’s currently being worked on concerning the sequential nature of the mission planning process (I got to learn about this through SmallSat 2020, so thank you to the folks from Uni of Stuttgart’s ISS for their presentation on IRAS’ new DCEP). Much like with the different elements of mission planning, these debris removal solutions are sequential. You do one piece of debris at a time, one after another, over and over and over again.
Just like with picking up grains of rice using a pair of chopsticks, that strikes me as hilariously tedious.
Now, I don’t know what the future of ADR will be necessarily, but I think I know what it’ll look like. It’ll have more in common with using your forearm than your fingers - a solution that can deployed on a large scale and eliminate debris en masse, while somehow managing to distinguish between active spacecraft and inert junk. Before you ask, no I don’t mean an auto-targeting laser cannon with 15 barrels. As awesome as that would be, it still doesn’t address the issue I’m thinking of, because it still targets junk one group at a time.
Mitigation (Obliquely)
Mitigation kind of works this way I think. Pre-installing de-orbit devices (or thrusters capable of also enabling rapid de-orbit without eating into your propulsion budget, kind of like the Calypso nudge nudge wink wink) is able to eliminate some of the tedium. All you have to do is flip a switch and large numbers of sats can de-orbit themselves.
But it doesn’t address the 8,000 tons of stuff currently up there. Even using an orbital tug to stick de-orbit devices on existing junk is still like setting up a row of dominoes - you might be able to knock them all down in one fell swoop, but you have to spend forever setting them up first.
So mitigation is a forward-facing solution. It’s important, but it only goes one way. What do we do about all the crap we’ve left up there thus far?
I’m just a blind man, trying to feel out his place in the universe
Okay here’s the part where I demonstrate why I’m a lawyer and not an engineer or scientist.
When I envision the future of ADR, I imagine flipping a switch that enables a massive Wile E. Coyote-esque magnet to pull old space junk out of the sky, while magically leaving all the useful stuff up there. Another Acme Corporation-sponsored idea: maybe a global network of autonomous, auto-targeting lasers trained to differentiate debris from active spacecraft could blast and/or gently nudge the junk out of orbit. I’m pretty sure this one’s being researched though, and it’s not as simple as just hopping on ImageNet.
[EDIT because I’m an idiot and I forgot about this part]: Oh, and there’s also GEO graveyard orbits. I haven’t gotten to thinking about that because it gives me a headache, but the whole issue does remind me of a short story I once wrote which featured clouds of roaming degree zipping around space and shredding random things and spacecraft like a horde of metal locusts. Whatever we do to GEO junk - whether we destroy it, send it out further into the cosmos, or repurpose them as novelty gifts for other star systems, the solution we’ll arrive at will require a totally different set of considerations from LEO.
So I don’t know what the future of ADR will be specifically. I’m guessing at the shape of things to come, but I can’t quite see the details of the picture. Whatever the future of debris removal is, I’m pretty sure it’ll kind of look like the forearm of God.
As for what the forearm of God itself looks like, I think I’ll know it when I see it. But I can definitely tell that it isn’t here yet.
Lastly, this really has nothing to do with space, but it’s National Day in Singapore today so I got to see tanks rolling down my street.
Now that’s a sight that makes me want to shout, “GAD DAYUM I LOVE BEING A SINGAPOREAN. PEACE THROUGH SUPERIOR FIREPOWER!”
Anyway, Happy National Day.