Here are the orbital stages above Venus low-orbit, that mighty toll-booth. For most Venus orbital stations, the orbit will be prograde solar / retrograde Venus.
Venus’ own L1 gravity-well happens to be a million km above the cloud layer. Below that, she got Sphere of Influence 616000 km but for long-termers, only permanent-daylight polars can rise even that high - orthogonal to L1/2, at that. Most satellites run below 536412 km. That is much further than Earth’s gravity-well although taken as a set the Earth-Moon system’s L1 is of course much further out than Venus’. This makes room for an effective infinity of orbital platforms.
The Main Station is SVL2. I expect many elliptic, short-period orbits with their apocytheria once a Venus year as close to the the top of Venus' umbra as we get, which again is 536412 km maximum. Those Hohmanns from other planets do it naturally. Anything between that and L2 isn't orbiting Venus, but - at best - the Sun behind it. Not to say it cannot be done. It's just that for statites we'll be floating small robots, not stations.
Up to 536412 km up, stations serve L2. Others are to boost ships to the outer planets directly, or to supply L4, or to catch supplies dropping in on Hohmann, or to receive sunside visitors here having made the long way home to Venus. Some farms should orbit in those higher altitudes also, given how much cheaper to ship goods down than up. Orbital farms make a full circular circuit, minimum 777 m/s. More elliptically so do my five 12:1 resonant hotels at 530567 km: for 48.66 apparent Earth days, sidereal 40 days for 782 m/s. UPDATE 1/15: They can get their phosphorous from comets. There are at least two Earth-facing outgoing stations, a cheap one and an expensive one - but the "expensive" one, with the shorter semimajor, will be the cheaper one to get into from Venus proper.
And there is another station at 9000km up, in Venus' magnetosphere, to harvest ionic H+, O+, He+ from what trails off of Venus' clouds [UPDATE 1/11: I think, among the first stations]. The inner orbit 2000 km (< 6370 ms-1) has people newly up from Venus.
Given insolation of 2620 Wm-2, solar is the main source of power when not in pen/umbra. Panels degrade under this much radiation, and also under exposure to micrometeors and to plain ol' flying junk. Patching and recycling solar panels is a major industry in orbit. Degraded solar panels are recycled for their silicon, not so expensive given this much energy coming in.
Moving from orbit to orbit is done with a special set of thrusters, for manoeuvrability. A shuttle newly from Venus' "surface", or caught from another planet, has its propellant-array removed, and refitted with the inner-orbit array - mainly solar panels. In the orbital tier, smaller thrusters are attached. On the outgoing stations nearest L1/2, also attached is a tether to a LARGE sail-type rig - hitching the cart to a horse. Those push craft to Earth and beyond. Ion drives might work to spiral more-valuable and fragile freight, but I get the feeling that these could just as well sail on the coma blasting from Venus' night side. For high-thrust, low-ISP we might suggest bi-elliptic transfer.
Most orbital-region thrust is powered from lasers, attached to each orbiting station. The most powerful lasers are on the outgoing stations. Maybe not on energy-poor L2 itself.
Besides the Main Station, most are standard ring habitats aiming at Venus G on the outside; low G for the dockworkers at the hub. Some hotels cater to Earth, Mars, Moon, and/or Belt as well.
Venus has no moon at present but some kind soul might chip in to throw something like Phobos at it, albeit into a higher orbit. This can store extra water, of which Venus needs rather a lot. It can also be a "momentum-bank" with a "tether" (I suppose I'm mainly trolling ol' Hop here).
Per habitat: incoming freight docks are in the space inside the centre. After offload, the freighters move to the outer rim, at about Earth G at 9.8 ms-2, with the Earth and Venus visitors and main staff.
SPLIT: These notes have been appended to "The Venus spaceport and embassy" over the past month. Time to house them in their own habitat.
CONSTRAINT 11/30: Sphere of Influence is not a million kilometers. It's, like, 61% that... TIGHTER 12/9: ... and for the polar-solars only. Half that for the rest o' y'all.
No comments:
Post a Comment