Between them, Landsats 7 and 8 image the entire land surface of Earth every eight days. The USGS orbiters are just two of many Earth observing satellites flying at the same altitude and collecting data at the same time of day. Other “constellations” of satellites gather other kinds of data, traveling one after the other like cars on a train to collect information that can be used independently or combined to produce models that help us understand the health and well-being of the planet. In this episode of Eyes on Earth, we learn about those satellites, the value they provide, and how their operators work together to insure the smooth and safe collection of scientific information.