Whip it good

A few years ago Charles Stross, a man I must disclose I don't respect, posted some ideas for the Musk Starship.

Stross hasn't posted what he thinks about Musk these days but I suspect he's waiting out the politics; if/when it doesn't go Musk's way, I am not hopeful for anything gracious. I also cannot rule out Stross will "fortify" his previous pro-Musk posts should that happen. So I'll excerpt this bit in full:

One serious proposal for a long-term Lunar presence requires the construction of a Lunar space elevator. This would not run from surface to geosynchronous orbit—the moon, being tidally locked, has no GEO—but instead to the L1 (near-side) or L2 (far-side) Earth-Moon libration points, 56,000 and 67,000 kilometers from the surface (points where the effect of the Moon's gravity and the effect of the centrifugal force resulting from the elevator system's synchronous, rigid body rotation cancel each other out and an elevator could be stable). Unlike a terrestrial space elevator sufficiently high tensile strength materials for such a tether already exist. There is, however, the slight problem of fabricating and shipping a 120,000 kilometer long cable out to near-Lunar orbit (and capturing a near-Earth asteroid to act as a counterweight). This is just a wild-ass Charlie guess, but I suspect shipping up 500 tonne cable drums will work out cheaper in the end than trying to build a carbon fiber factory in space (at least, until space industries are sufficiently developed to go the whole eat-your-own-dogfood distance).

Back in 2016 there was some "LiftPort Group", noted there, not really doing much since. The Lunar space-lifts looked more practical. So: if we have the capacity to send a 120 mega-meter cable to the Moon; why not a 60 mega-meter cable to SVL2.

What would SVL2 do with 250 tonnes and 60 Mm of rope? Well... as noted here, the SVL2 Lissajous region is in penumbra, which is Mars cool, but not superconductor cool. 60 Mm down from that will get you below 950 Mm altitude which is full umbra. More rope, more umbra to move about in. This works best when the SVL2 innermost counterweight is well above the 419.7 tonnes of the ISS; which we've already conceded isn't hurting for energy, tho' we'll want to work on the fuel.

We're not in Venus' gravity-well for another 470 Mm. Also our ions will be predominantly solar (so protonic), not Venerean. I don't expect a lot of strain on this rope. We can tether all sorts of goodies along it. Fiber-optics come to mind. Electricity relays. Robots to find and fix strains in the rope itself. Or just to pull in freight from a lower orbit.

Another fine idea is to spin the cable. Someone from lower orbit - who wants to Earth or to Mars - jumps to 950 Mm, grabs the tether, gets flung into Hohmann. That something doesn't expend the propellant or energy. These costs pass to the SVL2 station which, as noted, should be megatonnes.

Reddit tells us it's something like 360 m/s to get from E>V Hohmann to Venus high-orbit capture, tho' I recall Hop David claiming 400 m/s. From orbit to V>E Hohmann we need first to reach the tether's end so, first the shuttle burns its own supply, then pulls on the tether.

This will work best for small, low-propellant craft: like shuttles, or (Earthbound) whatever passes propellant-tanks from orbit to Hohmann. Also for Opposition Class trajectories the outer planets shift amongst themselves.