The December 2022 issue of IEEE Spectrum is here!

Close bar

Night Life as Seen From Space

Scientists plan satellite to snap pictures of cities at night

3 min read

11 September 2007--The size and shape of the ”human footprint” on Earth might best be seen from space--and in the dark, say scientists. Christopher Elvidge, a researcher at the National Oceanic and Atmospheric Administration's National Geophysical Data Center in Boulder, Colo., and his collaborators have come up with a concept for a satellite mission, called NightSat, which would take pictures of Earth's surface at nighttime with a high-resolution, low-light camera. The purpose is to obtain a complete, cloud-free map of all nighttime lights on Earth on an annual basis.

Lights serve as a kind of geographic marker of human activity on the planet: they tell us information about the location of settlements, how land is used between urban areas, how dynamic population growth and migration is, and what impact urban settlements have on a region's natural resources, weather, and climate. Analyzing changes in nighttime lights over time can provide a model of how human civilization is progressing on the planet and how its relationship to the environment is affected. The concept is simple, so why haven't nighttime lights been mapped already?

Keep Reading ↓Show less

This article is for IEEE members only. Join IEEE to access our full archive.

Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

If you're already an IEEE member, please sign in to continue reading.

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions
Two men fix metal rods to a gold-foiled satellite component in a warehouse/clean room environment

Technicians at Northrop Grumman Aerospace Systems facilities in Redondo Beach, Calif., work on a mockup of the JWST spacecraft bus—home of the observatory’s power, flight, data, and communications systems.


For a deep dive into the engineering behind the James Webb Space Telescope, see our collection of posts here.

When the James Webb Space Telescope (JWST) reveals its first images on 12 July, they will be the by-product of carefully crafted mirrors and scientific instruments. But all of its data-collecting prowess would be moot without the spacecraft’s communications subsystem.

The Webb’s comms aren’t flashy. Rather, the data and communication systems are designed to be incredibly, unquestionably dependable and reliable. And while some aspects of them are relatively new—it’s the first mission to use Ka-band frequencies for such high data rates so far from Earth, for example—above all else, JWST’s comms provide the foundation upon which JWST’s scientific endeavors sit.

Keep Reading ↓Show less