An orbiting array of reflective balloons

[Image: "An orbiting array of reflective balloons focuses sunlight onto the surface of Mars, providing extra heat and solar power for human colonists." Via New Scientist. The plan being illustrated here would specifically use "300 reflective balloons, each 150 metres across, arranged side-by-side to create a 1.5-kilometre-wide mirror in orbit." This would thus create "Earth-like conditions" on Mars – and perhaps inspire some strange future version of the Narcissus myth, in which a whole civilization turns its eyes to the nighttime skies... only to be confronted with an unmoving reflection of itself. What new astronomies are we doomed to construct? Of more earthly concerns, could we build small clouds of mirrored balloons, and – when our teenage neighbors aren't shooting them down – amplify urban solar power intake during the off-season? Manhattan, masted to a thousand clouds of silver balloons, all shining].

(Thanks, Bryan! Related: Pruned's Let there be light!)