Space Satellites

Satellites come in all sizes. The smallest satellite is the size of a loaf of bread. The largest satellite — the International Space Station — is the size of a football field. It took over 1,000 hours of extra-vehicular activity to piece together the station’s 159 separate components. Now it serves as a research laboratory for tens of countries.

The ISS is relatively easy to spot and dazzling, too, outshining the stars and any visible planets. But the ISS isn’t the only satellite to see. Of the roughly 3,000 spacecraft in Earth orbit, nearly 100 stand apart: the Iridium communications spacecraft. They periodically reflect sunlight toward the ground, causing brief but brilliant displays of light. Even the smallest CubeSats will be visible when they deploy to Earth in massive balloons.

Here Sky & Telescope editors help supply all the information necessary to spot these orbiting spacecraft.