In January 2022, space watchers were startled when a Chinese satellite suddenly moved from its usual path around the globe, docked with a derelict spacecraft and flung it into what's known as a "graveyard orbit". Shijian-21's move to get rid of the defunct weather satellite, Beidou-2 G2, was done during daylight hours, when it's hard for telescopes to observe satellites. It's a manoeuvre that would typically be celebrated. Decades of space flight have left the area above earth's stratosphere — the thermosphere and exosphere — increasingly cluttered, filled with dead satellites, abandoned pieces of rockets, and tiny pieces of spacecraft...