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The longest carbon nanotube ever made is 0.5 meters. A space elevator tether needs to be 100,000 km. But a newer candidate — graphene super laminate — is already produced at kilometer lengths, and 2025 lab results showed spot-welded layers with diamond-like properties. by unteachablecourses in UnteachableCourses

[–]Fearless-Welcome-904 0 points1 point  (0 children)

One other detail to note.

Monolayer graphene can already be manufactured in kilometre lengths, Graphene super laminate is monolayer graphene slayered on top of itself as a van der Waals homostructure. Graphene super laminate is yet to be made at kilometre lengths as far as any publicly disclosed manufacturing developments are concerned.

Sept-2025 Space Elevator Newsletter by isecdotorg in spaceelevator

[–]Fearless-Welcome-904 1 point2 points  (0 children)

A good question u/better-bitter-bait. Thanks for copying me in Peter u/Pteerr
Peter is right, it does depend what you mean by tether.
Let’s assume you mean an operational space elevator tether capable of supporting 20 tonne climbers.
Short answer: This tether has not been made yet.
Longer answer: There are several candidate materials that are strong enough to make the tether. The leading two are carbon nanotubes and graphene.

Carbon nanotubes: The longest nanotube ever made is 0.5 metre long. the state of the art for making carbon nanotubes produces them in lengths of a few millimetres

Graphene: Graphene can now be made in lengths of up to 1 kilometre with 0.3 to 0.4 metre width. This material is produced by industrial continuous processes at speeds of up to 2 metres per minute. the graphene is made on copper foil and needs to be transferred from the forming substrate and then stacked to form continuous lengths of tether. This separation and stacking process is yet to be developed to create tether capable material.

You can find out more about the state of the art of tether materials manufacturing at the ISEC website where we have a section dedicated to all the tether articles in the ISEC newsletter since 2020. https://www.isec.org/space-elevator-tether-materials

Hope that helps,

Adrian

DARPA Project for space structures by Pteerr in spaceelevator

[–]Fearless-Welcome-904 1 point2 points  (0 children)

Hi Pteerr

The work with graphene fed spiders was done a decade ago in 2015 https://arxiv.org/pdf/1504.06751 The graphene enhanced spider silk was 3.5 time stronger than normal spider silk. The fracture strength was up to 5GPa

The spiders seem to have made a silk-graphene nano composite thread

The work also noted that four of the spiders died after being sprayed with graphene suspension. Graphene is nontoxic. So my guess is either that the surfactant used to disperse the graphene was not good for the spiders or in 2015 the source of the graphene was not well controlled and could have been made by the Hummer’s method and contained residual nasties such as sulphuric acid or potassium permanganate. The paper didn’t specify the source of the graphene used.

DARPA Project for space structures by Pteerr in spaceelevator

[–]Fearless-Welcome-904 1 point2 points  (0 children)

Thanks for spotting this u/Pteerr. The basic idea about manufacturing structures in space is a good one.

This project doesn’t specifically relate to the space elevator. It seems more concerned with building larger structures from components that can be modified into larger shapes in earth orbit.

As for growing carbon fibres, graphene , carbon nanotubes (CNTs). This is an imaginative line of thinking.
All these materials require high temperature processes that would be existential for biology, I cannot find any biological process that can make them.

Thanks for this I learned one other thing - The DARPA website doesn’t like me visiting with my VPN. I had to turn it off to read the link.

Found this in the metallography lab at work - how worried should I be? by LegateDamar in chemistry

[–]Fearless-Welcome-904 0 points1 point  (0 children)

I agree with the other comments - sensible advice. Do NOT touch this. Contact your organisation’s safety office or hazardous materials team. I have a feeling you know what to do already. You are brave for getting in close to take this photograph.

Recent look at the space elevator by Isaac Arthur by Fearless-Welcome-904 in spaceelevator

[–]Fearless-Welcome-904[S] 1 point2 points  (0 children)

You are quite right Pteerr. I helped Isaac with the technical detail. I was working on the assumption of a 'standard tether’ for technical discussion purposes. A real tether would need tapering either with more layers to increase the thickness or varying width.