Space junk mission deploys from the International Space Station | Hacker News Reader

Space junk mission deploys from the International Space Station

gov.uk

113 pointshappy-go-lucky40 comments

If anybody is interested in some fiction around this topic, there's a pretty good Japanese Manga/Anime series called Planetes that revolves around a group of "space janitors" who have to clean up space junk.

https://en.wikipedia.org/wiki/Planetes

Also Neal Stephenson's Seveneves, for an extreme space junk problem after the moon mysteriously breaks apart.

Both of those and others are mentioned here:

https://en.wikipedia.org/wiki/Kessler_syndrome

That novel is a work of a legend. Especially, the future part. Ecen Christopher nolan won't be able to do justice to this novel.(maybe he could)

Has his writing style improved since Snow Crash and prior works? I don't think I can handle slogging through another Stephenson novel.

Well, i haven't read Snow Crash. I read about it on wiki and decided to skip it. But i admit, while I was reading i got bored in between because pace had slowed down and then I skipped a few dozen pages , read a few lines and skipped way more and read more because wanted to know about the end as I was becoming really impatient. Anyways after reaching the end, i felt guilty that I skipped through a lot. A few days later I started reading again from the point I began skipping and in the later parts , i got to know that I had misunderstood some parts while skipping, so it turned out to be a blessing in disguise. Also, some space stuff would have been better explained with a rough diagram. I guess, I got bored in between because I was reading a novel after a really long time. also, I got to know about Neal and this novel via Bill Gates' summer reading list a few years ago.

I would say Seveneves was more science focused than Snow Crash, which made it a better fit for his style. If the science bits don't do anything for you, I mean, ...

It appears Ron Howard will make an attempt.

https://en.m.wikipedia.org/wiki/Seveneves#Film_adaptation

I've thought a lot about how Seveneves could be adapted, and man ... it's going to be a tough thing to pull off. A movie trilogy might be able to cover half of it. Were I to do it myself, I'd probably go for a three-season TV series, with each season being one of the parts of the novel. I have no doubt that there's a ton that can be cut from an adaptation, but I'd be hard pressed to cut much, personally. I'm very bearish on any potential adaptation to a single film, as much as I'd love to see one happen.

Whoever attempts it should try soon because then the people that Stephenson actually modeled his characters after could play the roles in the film/TV series. For instance, one of the characters in the first part of the book is obviously modeled on Neil DeGrasse Tyson.

yeah. Even that head of rocket company seems to be a bit inspired by Blue Origins/SpaceX. Neal has worked for Blue Origins in some capacity. Also, TV series would be much better because it's spread over a number of episodes giving a sense of time.

I'm posting to second this. It is a genuinely well-done show, and the creator made it a point to be as accurate as the plot allows regarding orbital mechanics, ablation cascades, and the like. It is well worth a watch.

Yep, the comics Planetes 1 and 2 are brilliant reads!

I never read the manga but the anime is great!

Kind of sad ending for that cute, useful, little box to just burn up in the atmosphere.

Makes me wonder if this is actually a viable approach on a larger scale, in terms of resource costs? Or is the "burn it up at the end" just part of this specific experiment and future versions won't have to be disposed of like that?

Surely, de-orbiting is how you remove the space junk from orbit.

Agreed on the junk, but does the satellite itself really need to be burned too?

With the amount of space-junk floating around it might be kinda wasteful to burn the whole thing with the junk, that's why I was wondering about reusability of the satellite itself.

Why are they not experimenting with using photon momentum from a laser to push debris into the atmosphere? It seems ideal for small high-velocity garbage. Perhaps that's too close to weaponizing a spacecraft?

If you can track something accurately enough to hit it with a laser (especially for the length of time needed for photon pressure to work) then it's better to leave it alone- you know where it is and it's predictable enough that you can screen against it.

This is one of the (many) things Philip Lubin has looked at. The momentum transfer from photons is far too low. However this can be partially fixed. A laser can vaporize part of the trash and then heat up some of the vaporized material, effectively turning the ablated material into a small rocket. I am not entirely sure how much more effective this is, and if it is enough to be a viable technology.

alignment of forces would be a real pain. I expect the little rockets would just spin the item around. Also, I would expect much of the existing space junk to already be spinning in random directions for this approach to be really difficult. (didn't read the article - perhaps it's explained there?)

You could disperse* the beam over the entire object to even out any added rotational force. *whether by increasing beam diameter or sweeping beam across the object's face.

I think there are issues with weaponization. Developing a space laser with sufficient power and the guidance system to go with it may trouble international treaties against weapons in space. I love the idea of dragging the rubbish down in a net, very low-tech.

Not looked into the technology, but wouldn't it need to put a ridiculously strong laser to have any effect on garbage at all? Solar sails have to have a really large surface area and a really low mass in order to get even a tiny amount of acceleration from photons, I don't see how we would be able to focus enough momentum onto tiny pieces of garbage in order to cause their orbit to decay.

Depends on the size of the garbage? Even paint chips with sufficient relative velocity are a danger to the ISS. The laser would have as much time as it needs to de-orbit something and a limitless power source.

Suppose your laser-zapper spacecraft is solar powered. The force of the sun on its solar panels is approximately the same as the force imparted by its laser beam on the target garbage.

This is to say nothing of the propellant required to transfer the laser-zapper spacecraft into the same orbit as its target garbage.

The biggest benefit of a laser solution is that it doesn't need to be in the same orbit. It needs to regularly intersect the target's orbit (or at least close enough to get in the laser's effective range) but that's a much cheaper maneuver.

What would the effective ranger of a laser in nearly gas-free environment like space be? How precise of laser collimators are we able to build?

In general, at the power levels in question the limiting factor is diffraction, not beam quality. There are a lot of variables going into it, but the numbers I've seen bandied about for orbital systems are on the order of 100km. See e.g. here: https://www.sciencedirect.com/science/article/pii/S100093611...

(Or, for a more speculative take, here: https://childrenofadeadearth.wordpress.com/2016/07/02/the-ph...)

The cost of failure is rather high. In 2007, China used a missile to destroy one of their satellites:

"This event was the largest recorded creation of space debris in history with more than 2,000 pieces of trackable size (golf ball size and larger) officially cataloged in the immediate aftermath, and an estimated 150,000 debris particles.[24][25] As of October 2016, a total of 3,438 pieces of debris had been detected, with 571 decayed and 2,867 still in orbit nine years after the incident."

https://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_mi...

That being said, they are researching the use of lasers to clean up space debris: https://www.sciencedirect.com/science/article/pii/S003040261...

What exactly did they expect to happen by blowing it up? It's not as if it was going to just make it, and itself disappear.

That seems to be a great idea.

Unlike the "humanity star" initiative, a highly reflective object in space designed to cause as much light pollution as possible. Something needs to be done to prevent that from happening again. Our survival as a species depends on reliable astronomy.

The Humanity Star was visible only for short periods of time at dusk and dawn (which are not astronomical observing hours) and was, at brightest, approximately magnitude 2. Less bright than many stars and planets, as well as many existing satellites. In addition, it only stayed in orbit for about 6 weeks (although it was intended to last 9 months).

Isn’t the simulated space debris actual space debris?

Yes, but it is already in a decaying orbit and will fall/burn up within a few months. The ISS has to be reboosted routinely in order to keep it in orbit.

Yes, though depending on the part we are talking about it can take up to a couple of years. The mission has been designed to avoid creating small untrackable debris and everything is below the ISS.

Fun fact, as all the missions deployed from the ISS, the RemoveDebris satellite is already classified as a debris in the NORAD satellite catalogue.

What about simple deflection into the atmosphere - an inverted pyramid?

What was the point of harpooning something already attached to an arm? (see video)

The goal of the experiment is to test the harpoon itself. You could have a moving target but then it creates a constraint on tracking a non cooperative target and orientating your harpoon accordingly, which is quite a feat in itself. Also, by having it on the spacecraft, it allows observing the impact point later on with the in board cameras.

Well, many years later than everyone else, plucky little Britain finally gets into space - to collect the trash. Great!

Not actually everyone else: https://en.wikipedia.org/wiki/Prospero_(satellite)

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