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TL;DR we can stretch a really long piece of fishing line from the Moon's surface to geostationary orbit. And we can probably send payloads to the moon by dockin

by gene-h 7y ago

TL;DR we can stretch a really long piece of fishing line from the Moon's surface to geostationary orbit. And we can probably send payloads to the moon by docking with said cable in geostationary orbit too. The funny thing is I literally mean fishing line here, they call for using a constant cross section cable made of zylon or dyneema with a diameter of about 0.35 mm. At least initially. Both dyneema and zylon with this about this diameter are sold as fishing line. Initial payload to/from moon seems a bit low as the line at the Moon end can only support 100 kg. The dynamics of such a thin, flexible cable which passes through an unstable(!!!) lagrange point should be interesting. We know that very long space tethers can behave in weird ways[0]. This idea is crazy and attractive enough that it warrants further investigation to at the least find out what the problems are so other people don't make the same mistake. [0]https://pdfs.semanticscholar.org/6aff/70794d94b8979d0c5a67fff7c2500cda082d.pdf https://pdfs.semanticscholar.org/6aff/70794d94b8979d0c5a67ff...

pavel_lishin 7y ago
> Initial payload to/from moon seems a bit low as the line at the Moon end can only support 100 kg. But on the Earth-side, it can support up to 2000kg! And launching from the Moon is cheaper, anyway, since it's a less massive object than the Earth, and there's no atmosphere to deal with.
- hanniabu 7y ago
  That's interesting, I wonder if they meant 100 Earth kilograms or 100 moon kilograms. Edit: On 2nd thought they are probably using kg in terms of mass, not weight.
  - db48x 7y ago
    Grams are always mass, never weight.
monomyth 7y ago
I am not sure what's more exciting: passage through an unstable Lagrange point, or effects of a solar wind on the massive area of such cable.
Pfhreak 7y ago
> TL;DR we can stretch a really long piece of fishing line from the Moon's surface to geostationary orbit To the height of geostationary orbit. The actual endpoint wouldn't be geostationary, as the moon orbits the Earth, it'd be pretty difficult to keep one end of a line in a stable spot above the earth's surface.

by gene-h 7y ago

pavel_lishin 7y ago

> Initial payload to/from moon seems a bit low as the line at the Moon end can only support 100 kg. But on the Earth-side, it can support up to 2000kg! And launching from the Moon is cheaper, anyway, since it's a less massive object than the Earth, and there's no atmosphere to deal with.

hanniabu 7y ago
That's interesting, I wonder if they meant 100 Earth kilograms or 100 moon kilograms. Edit: On 2nd thought they are probably using kg in terms of mass, not weight.
- db48x 7y ago
  Grams are always mass, never weight.

monomyth 7y ago

I am not sure what's more exciting: passage through an unstable Lagrange point, or effects of a solar wind on the massive area of such cable.

Pfhreak 7y ago

> TL;DR we can stretch a really long piece of fishing line from the Moon's surface to geostationary orbit To the height of geostationary orbit. The actual endpoint wouldn't be geostationary, as the moon orbits the Earth, it'd be pretty difficult to keep one end of a line in a stable spot above the earth's surface.