The Sweep

The Sweep (2170s–2240s). No elevator cable could cross a debris belt, so the Elevator waited for the sky left by the Shattering of the 2080s to be cleared. The Sweep was the first lasting project the future blocs ran together. Ground lasers burned the surface of fragments so that they dropped and burned up; drag sails were fitted to dead satellites; robotic collectors cleared the high band, where nothing falls on its own. Much of the low band had decayed by itself, but the White Night of the 2140s added a new layer of dead satellites, and the low band was clear only in the 2180s, in time for the early Great Lift to run, slowly, on rockets and fusion shuttles. The high band took sixty years more. A laser that can drop debris can also blind a satellite, so the Sweep ran under mutual inspection: the Sealing Treaty's first test off Earth. The Elevator Treaty of 2244 was signed in the year the Sweep's last high-band survey came back clean, and its drafters added the Sweep to their precedents (see Who built it, below). The Landing still keeps the orbits around every cable clear, and leaving junk in orbit is an offence under every bloc's law.