Cloud Cities of Venus: Settling Earth's Twin

Four billion years ago, Venus, Earth and Mars each held the promise of supporting life, with oceans, supportive climates, and the chemical ingredients of biology. Over the eons since, Mars lost its atmosphere, turning ever colder, while Venus entered a death-spiral of ever-increasing heat. But, 50 km above its desolate surface, the cool cloud tops of Venus offer a potential refuge. This zone is protected from cosmic and solar radiation overhead and the blistering surface temperatures below.  Solar powered