Humanity trashed Earth orbit – next stop the Moon

INTERVIEW On August 5, a spent Falcon 9 upper stage is expected to crash into the Moon. Humanity has not done a great job of looking after the space around Earth. What could be done differently around the Moon? How about lunar scrapyards? Chiara Manfletti, CEO of satellite collision avoidance business Neuraspace, reckons one …

[Eclectic Man]

Recycling

dumping grounds where material can be deposited, collected, and recycled

Whilst I appreciate the sentiment, unless there are a lot of items deposited in one small part of the lunar surface, surely the costs of getting there, even from a permanent lunar base, collecting the stuff and recycling it would be excessive? The 'dumping ground' would have to be far enough away from any Moon Base to avoid the chance of killing anyone when depositing the junk, yet close enough to be collectable. Unless it would be a controlled and very accurate lunar landing like the Falcon 9's on Earth I cannot imagine that wandering about the Moon looking for bits of a 'rapidly disassembled' former spacecraft would be a worthwhile use of astronaut time.

Techy readers please advise.

[Maurice Mynah]

Re: Recycling

I think we may refer the enquirer to the seminal work of Anderson & Anderson* for detailed scenarios of the risks of lunar waste disposal.

* Gerry & Sylvia.

[MiguelC]

Re: Recycling

That work is *so* last century

[Paul Crawford]

Re: Recycling

But we got to party like it!

[Excused Boots]

Re: Recycling

You just wait until September 13th 1999 - oh no hang on a minute.

[AVR]

Re: Recycling

Ores on the Moon are mostly awful, as far as we know. A total lack of water concentrating and separating the ores, and a lot less in the way of rocks melting underground and being returned to the surface (well, once, but not repeatedly). If you could drop bits of rocket 50 km away it might be worth collecting the metal if you were desperate to manufacture on the Moon. You would have to be desperate though because as you pointed out this is not an automatic process.

[ArguablyShrugs]

Re: Recycling

Rockets are mostly aluminium. Plenty of Al2O3 and other metal oxides in the lunar regolith.

Any spent stage inserted into a loose lunar orbit with perilune of 0 km will impact the surface at hypersonic speeds (speed of sound in the loose regolith, not the rarefied lunar exosphere or Earth's atmosphere), which means the impact will be a hypervelocity impact with all its assorted fluid dynamics.

No going around that, unless you add enough propellant for a landing, which is quite infeasible for a graveyard. Your spent rocket would need about double the propellant to land on the moon.

In a hypervelocity impact, any aluminium and titanium from the rocket would be scattered all around the crater and thoroughly mixed with the lunar regolith, and quite possibly also oxidised if any oxygen gets liberated from the fluidised regolith.

Thereby any recycling of said spent rockets would take sieving and extracting hundreds of tonnes of lunar regolith, at which point you are basically mining and processing lunar regolith on a large scale anyway. Much easier to just mine it in places of high titanium and aluminium content and reduce the oxides there.

The whole idea of recycling spent rocket stages impacting the Moon is just dumb. It's only just remotely feasible if you can land them there, which means lugging so much additional propellant it makes the whole thing unfeasible again.

[Bebu sa Ware]

dumping grounds where material can be deposited, collected, and recycled

Given the Moon doesn't possess a significant atmosphere the dumped material is likely going to smack into the surface at a fair pace which pretty much brings you back to mining and refining once you dig it out and separate the regolith from the molten mass.

Might make more sense to have a structure orbiting the Moon whither discarded material could be slowly shuttled by a fleet solar powered ion-drive craft and tacked on to the mass like the old fashioned ball of salvaged string. We were once a thrifty lot — hard to imagine in these profligate times.

An interplanetary rag·and·bone firm ? Steptoe^†& Son's Celestial Salvage & Scrap (by appointment to Karen Caeli, Imperator Martis.)

_{† Sanderson I think for the sinistral side of the pond.}

[Eclectic Man]

Re: dumping grounds where material can be deposited, collected, and recycled

a structure orbiting the Moon whither discarded material could be slowly shuttled by a fleet solar powered ion-drive craft

OK, but only if the orbital structure and fleet are made of less material than they recover would that be at all economical.

Maybe we could try it out in Low Earth Orbit first, after all there is reputedly a lot of junk up there just waiting to be 'recycled' along with all the starlink and old spy satellites.

[KarMann]

Re: dumping grounds where material can be deposited, collected, and recycled

Bonus points for 'Karen Caeli'; have one of these.

[james 68]

Re: dumping grounds where material can be deposited, collected, and recycled

A space hulk, you are advocating for the production of a space hulk. They never end well. Next you'll want a supreme being to become emperor and be sat on a golden throne.

[Philo T Farnsworth]

Re: dumping grounds where material can be deposited, collected, and recycled

> † Sanderson I think for the sinistral side of the pond.

Close, sort of. Just for the record, the Steptoe and Son adaptation here in the States was called Sanford and Son, starring Redd Foxx and Demond Wilson.¹

But who you callin' sinistral, bub?

______________

¹ Wikipedia: Sanford and Son

[DS999]

Re: Recycling

Yeah I think recycling is a spurious argument, but keeping all the trash in one spot (or maybe two or three spots given different orbital insertions) sounds better than letting it just fall wherever in an uncontrolled manner. Given that there's no atmosphere, it should be possible to exert quite a bit of control over where it goes down. At least for those objects where you still have any control over them versus failed or completed spent boosters or whatever.

[doublelayer]

Re: Recycling

You could dump things in one place, then when you're going to build a base on the moon, intentionally put it right next to that location. Benefit: people can go out and get whatever was dumped as easily as possible, only a benefit if it's practical to recover anything useful from that but I think we're all assuming that for any of the rest of the hypothetical to work*. Cost: after that base is established, you'll have to dump new things somewhere else to avoid pelting it with shrapnel. If the base has a major secondary industry as a recycling facility, that could make sense. Otherwise, probably not.

* Since we mostly don't have that ability, even here with all the nice heavy machines we can't operate on the moon, there's reason to question this idea. This strikes me as one of those ideas that works if we assume that new tech will just start existing because we want it without considering its feasibility. This is only valid in science fiction books, and even then only at the beginning when the setting's tech level is established. In other situations, especially when it's someone's solution to why they don't have to do something properly, it's unconvincing pseudofuturism.

[MachDiamond]

Re: Recycling

"unless there are a lot of items deposited in one small part of the lunar surface, surely the costs of getting there, even from a permanent lunar base, collecting the stuff and recycling it would be excessive? "

If there is any manufacturing done on the moon, it won't be as expensive to get raw materials from such a dumping ground as it would be to try and mine and refine them from the lunar regolith. A robotic dump truck with claw on the end of a crane arm would be useful.

[Zack Mollusc]

Lumpiness FTW!!!

I seem to recall that there are very few stable lunar orbits, so the likelihood of any particular discarded lunar transfer stage staying in orbit long enough to cause problems is quite small.

[Spherical Cow]

Re: Lumpiness FTW!!!

Yes, but the flip side of that lumpy gravitational coin is discarded orbital hardware coming down in random places willy-nilly, which could be a headache for any people mooching around on the surface.

[mevets]

This is a Great Idea!

"We don't have a single body," says Manfletti, "that can speak, and then everybody says: 'Oh, fantastic! They have spoken, and we shall do it!' It's not how it works."

We could setup membership of all the nations in the world, have them meet regularly, and justly regulate international and interstellar affairs.

A sort of United Nations Organization.

Brilliant!

[Paul Herber]

I foresee a Lunar Mining Corporation, then a Martian Mining Corporation, even a Jupiter Mining Corporation!

That'll dwarf anything on the moon, especially as there is no atmosphere, and it's cold.

Fun.

[ecofeco]

Joke I heard the other day

I'll probably mangle it, but here goes:

Two aliens are passing by earth. One says to the other, "I see they have satellites in orbit.They must be intelligent."

The other says, "I dunno, they are all pointing at the inhabitants."

[Anonymous Coward]

Space 1999...

Why are all our tech overlords trying to recreate all the doomsday scenarios from TV?