In the spirit of “Don’t saying anything if you can’t say something nice” – All I can say about this article is – It is great that people are looking in to solutions for ocean plastics including this sort of article. Sometimes hard problems are solved by someone asking ‘why don’t we solve xyz by doing abc?’. I had hopes that this might be one of the occasions but after reading the article I sadly doubt that this is one of those times.

The difference is that things in space have an orbit that is calculable (be that in synchronous or decaying orbits). In other words, if you missed it this time round, it will be in position B on the next orbit. Things drifting on the ocean currents? You get one and only one opportunity to pick up and collect it (unless you pick up your sooper-dooper-plastic-scooper and move it). Actually, thinking about it that more or less equates to a space-sooper-dooper-scooper missing it on the first pass and having to expend fuel to go up or down to catch it on the next go-round. In other words, I’ve painted myself in to a corner and it is a 1-1 in terms of practicality (or 0-0 for the pragmatists) .

My next thought was – Sheesh – how wide would the net/catcher/sooper-dooper-scooper have to be to catch debris in space versus on the ocean. That lead to some fascinating internet research on exactly how precise GEO satellites are these days (in terms of is a 0.5/1/5/10/20/100/1000 mile variance ok?) In other words – how wide of a corridor would your sooper-dooper-space-scooper have to be in order to be effective versus how wide your sooper-dooper-ocean-scooper would have to be. Needless to say, answers varied from the “we don’t talk about fight-club” through to Wikipedia levels. Best answer I can provide is to DDG how precise GPS satellites need to be and then scale it to the earths’ circumference. Maths is hard, especially space maths but to save you the pain - I painted myself in to a corner again.

Current score 2-2 (or 0-0).

Next, on to using machine vision to identify and target. Here there is a clear victor. Consider the difficulty of the following – Detecting any object that shouldn’t be there (in space) versus detecting ‘something that glitters/differs from the background sea color’. Is it a fish? The sun glinting on the waves? A bit of plastic? Have to give a goal to the space sooper-dooper-scooper here.

Current score 2-3 (or 0-1).

Now on to the thing that I really wanted to touch on.Chaos theory. Yum. Specifically the Butterfly effect ( https://en.wikipedia.org/wiki/Butterfly_effect ) As mentioned earlier, orbits are calculable. A single piece of plastic drifting on the ocean affected by winds, tides, passing ships, storms, a dolphin playing tag with it etc etc etc?) That right there is supercomputer level hard type math with a (charitable) less than 100% degree of certainty (think weather forecasts and the computing power used to calculate the probability and paths of major events like tornados). Those are a lot bigger than a floating rubber duck (28,000 Rubber Ducks Accidentally Fell Into The Sea In 1992
https://www.ranker.com/list/rubber-ducks-friendly-floatees-o... )

Current score 2-4 (or 0-2).

Now, on to the thing that makes me think that the problems of space debris are easier to solve that the problems of plastics in the ocean. I remembered reading something from a few years back that more or less was about an island of garbage floating in the North Pacific. Searching for references turned up some debunking (which was a shame since I wanted to make the point of “if we haven’t hoovered up the ocean plastics neatly gathered in a neat bundle for us then why haven’t we done it yet?) (ref The Truth About the Great Pacific Garbage Patch http://factmyth.com/factoids/there-is-a-plastic-garbage-isla...)

Current score 2-4 (or 0-2).

Wow. You made it this far? I’m amazed and will try to trim down some of the wall of text.

Here is the TLDR; Space sooper-dooper-scooper advantages? Harvesting solar energy to blast a stream of ionized particles to blow space debris down further versus the butterfly effect. Ever seen those industrial machines that use a blast of precisely timed air to blow defective products off to one side? Then you have a rough idea of the concept.

Current score 2-5 (or 0-3).

The only transferable technology might possibly be the ‘Sticky Net’ concept https://www.surrey.ac.uk/surrey-space-centre/missions/remove... . There is some research on an unrelated field that uses synthetic spider silk (versus the toxic to marine life formulation) space spray foam approach.

The biggest problem with that is that in a space orbit – anything that shouldn’t be there can be considered ‘garbage’ and for removal. Doing that in the ocean where the ‘thing’ could be a fish, a jelly-fish or a piece of plastic? Way too much risk of collateral damage.

Certainly food for thought although I make the final score in terms of practicality 2-6 (or 0-5). There needs to be a solutions to ocean plastics but this ain’t it.

Armchair Quaterback aka Personal opinion only.

[Edit to add] I overlooked the elephant in the room. Monitoring who throws what, where and when in to space is a solved problem so it is a 'clean once and done' type task. Tracking who threw that plastic bag in the ocean and when/where? Not possible.