Dutch astrophysicist Dr Fred Jansen is no stranger to the difficulties of space exploration. He led the team that put an X-ray observatory in orbit in the 1990s, and has since overseen exploration operations to Mars and Venus. But the Rosetta mission manager described his latest challenge as the most difficult yet.
It took a NASA satellite 312 orbits around our planet to capture 2.5 terabytes of imagery. The data was then mapped onto existing Blue Marble photographs to create the Black Marble series. The satellite used a special new imaging system that can detect extremely dim signals. Scientists removed certain non-human-generated lights (e.g. gas flares, auroras, reflected moonlight) from the frame in order to have the photos only show artificial city lights (some wildfires remain, though).