Anyone fancy terraforming Venus?
Here's a sun-synchronous Venus parasol, which blocks just enough of the solar disc to drop the level of illumination to Earth normal. These things are so big they're affected by radiation pressure, so can't sit precisely at the stable L1 libration point between the Sun and Venus - it needs to be a little sunwards of that point. How far sunwards depends on the density per unit of area of the material the parasol is constructed from - the lighter it is, the further sunwards it sits at equilibrium. But the further sunwards it goes, the bigger it has to be to provide the same amount of shielding. So I've chosen the minimum-mass configuration.
This is still close enough to Venus to give a slight awkwardness from
the variation in line of sight across the Venusian disc - at Venusian
sunrise, you'll see the parasol dangling slightly off one side of the
solar disc; by midday it's centred on the disc; and by sunset it's
dangling off the other edge. This will allow just a tad more insolation
at sunrise and sunset, but the mass penalty of moving the parasol
farther from Venus to prevent this effect is huge.
3 Feb 2006
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