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Comment by westurner | Hacker News Reader

What would it cost to deorbit those rogue and derelict 50 safely and with intentional consensus, maybe as a post-orbital insertion deployment secondary mission?

When will it be safe and cost-efficient to - instead of deorbiting toward Earth's atmosphere - Capture and Haul and Rendezvous and gently Land orbital scrap on non-earth locations like the Moon or Mars or a thrust-retrofitted asteroid for later processing?

Would ISS be more useful as an oxygen tank in earth-moon orbit than in Earth's atmosphere and ocean?

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It's not going to be cost-efficient to move to the moon unless and until there is commercial demand for scrap material on the moon and equipment to process it. A lot of delta-v is needed to transport stuff to the moon. On the other hand stuff in LEO naturally deorbits with a certain timeframe and can be accelerated with a small nudge, a dragsail or possibly even laser ablation, and it's really not very far to go if you decide to actively deorbit it.

You'll likely get recycling in orbit (where the spacecraft are) before the moon (which has abundant aluminium anyway) first, so the compromise would be shifting debris in LEO to storage orbits with longer decay times

Tethers.inc thought they had a plan but their test tether cooked itself considerably faster than they expected and they sort of fell off the media radar after that.

Just get the space debris section on the case https://en.wikipedia.org/wiki/Planetes

Maybe once in-space manufacturing and refueling become reality, scrap recycling will make more sense beyond Earth

Do we really want to start junking up the moon?

Having a pile of junk ready when you want to start a permanent base sounds like it could be useful.

The amount of tools needed to process that junk and make newly usable stuff would be huge and not worth it. Not even talking about the energy needed to take the junk there and land it safely. The article is talking about rocket bodies mostly: they don't have that much useful material.

Please explain that to my wife in reference to my collections in the garage.

"It might be useful some day"

If it's iron or aluminium, someone probably will pay silly (Earth) money for it on the Moon during early colonisation, but maybe not right at the start when there's no bandwidth it facilities for recycling scrap. Right up until the bigger regolith smelters come online.

The box of pre-loved Beanie Babies, perhaps also quite valuable: who knows how much hydrocarbons will be worth in early lunar colonies. Carbon isn't especially abundant in regolith (compared to silicon, aluminium, iron, etc) and has to be baked out as gases. Though I still doubt you'd have takers if the shipping isn't included...

Thank you for inspiring my next project. I shall do all in my power to relocate the contents of my garage to the lunar surface.

Does anybody have Tom Mueller's phone number?

Best I can do is this very old card I found for a Mr von Braun, I think it is. It's in a very, um, spiky font.

That will do. I don't need reusability, and London makes for a decent Plan B target.

Hydrogen moreso!

Oxygen is usually plentiful in various minerals, but hydrogen tends to get blown into space if there isn't a reactive atmosphere to recapture it.

Yes indeed. Apparently some of the carbon will come along with hydrogen as methane when you bake it out of the rock. Separating straight to carbon and hydrogen is a hassle, though, as the carbon clogs the catalyst.

Perhaps crashing a carbonaceous asteroid into the moon or disassembling in orbit and landing the results may work?

Of course.

If Starship achieves full and “rapid” reusability then it seems like it would be a lot more feasible to collect and deorbit space junk.

Most of the list is rocket bodies which are quite large, and rendezvous is already challenging when everybody is collaborating, rendezvous with a tumbling uncontrolled giant piece of junk is even more difficult.

Astroscale is working on that in collaboration with various space agencies, they're currently planning a mission (ADRAS-J2) to connect to an uncontrolled rocket body and deorbit it circa 2027: https://arstechnica.com/space/2025/02/astroscale-aced-the-wo...

Theoretically, a cheap option is to modify Starlink with enlarged argon tanks to rendezvous and "shepherd" large debris into lower orbits. Add LiDAR (DragonEye) and "Push Me Pull You" argon thrusters and it can exert a gentle push even when the debris object is uncontrolled and tumbling.

I'm somewhat surprised SpaceX hasn't tackled this problem yet. Even including just one StarCleaner every 2-3 Starlink launches could make a huge difference.

SpaceX even has the perfect test satellite. RatSat was their first successful launch in 2008, and it's barely decayed despite saying it would only last five to ten years.

https://forum.nasaspaceflight.com/index.php?topic=44753.0

Starship lowers launch costs. One can launch more Astroscales with Starship.

It’s not necessary. But it helps turn what is currently research curiosity into something someone can fund at scale.

You can deorbit things by pushing them "up" from Earth which lowers their perigee on the other side of the orbit.

A ground based high energy laser could ablate material from Earth which would provide propellant mass and incrementally knock objects into deorbiting trajectories.

And what happens to the ablated material? One large stage that is easily tracked via radar is preferable to tens or hundreds of milimetre size chunks that could potentially flake off while ablating the surface of a rocket stage or derelict satellite.

Ablation turns the material into individual molecules.

Yes, when done perfectly in a lab. Under less than ideal conditions, temperature gradients cause cracks and then flakes are released and expelled.

Drag brings those flakes to the ground.

Flakes of solid material are typically far more than dense than structures made of the same material. Therefore flakes' orbital lifetimes are likely longer than structures made of the same materials.

Pushing "up" on an orbiting body causes no change to the altitude at the other side of the orbit (that is, 180 degrees around the orbit). However, it does raise the orbital altitude 90 degrees ahead, and lowers it 270 degrees ahead.

That tumbling should be conveniently predictable in absence of aerodynamics, but then even the best prediction would leave you with a tough nut to crack. I guess trying to solve that problem could be very helpful as a reality check to reign in any space mining fantasies?

And to answer the cost question, Astroscale is charging $8-100 million [0] per LEO junk removal mission (small numbers for small failed comms sats, big numbers for a spent upper stage).

The objects in the article are all at the bigger end. Presumably Aeroscale have started with a technically easier mission than some of the 50 in the article, but they will also eventually benefit from economies of scale. So you can estimate the cost to remove the 50 bodies in the single digit billions.

[0] https://www.kratosspace.com/constellations/articles/astrosca...

"Is charging" for an activity which is wreathed in hypotheticals. Surely it's "proposes charging"?

No, it's signed two contracts already according to the link.

I'm sure the contracts are more complicated than "this amount of money for this job" but the price, at least, is not hypothetical.

Starship launch costs are hypothetical, but pundits are estimating one to two hundred dollars per kg, or about ten million per launch. This would shave a significant amount off the cost of launching something big enough to de-orbit a large target, like an upper stage. Still, even if you spitball a figure like 20 million for each removal that’s still a billion dollars in total.

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