Measuring height over time is something many of us do without thinking, for instance when families mark their children's growth on a wall and write the date beside it. That simple act creates a time series of height measurements. Satellite altimetry works in much the same way, but instead of just one child, it tracks the height of Earth’s dynamic surface -- its oceans, ice, land, and vegetation -- all around the globe. First proposed in 1969, satellite altimetry has steadily advanced, providing consistent and repeated measurements from space. By 1991, the European Space Agency's radar altimetry missions were underway for ice, starting with ERS-1. In 2003, NASA launched its first laser altimeter (the Ice, Cloud and land Elevation Satellite (ICESat)) to further refine our understanding of ice, land and vegetation. The currently-operational missions are ESA's CryoSat-2 and NASA's ICESat-2 and GEDI. These satellite “growth charts” show us where and how Earth is changing, whether it’s melting ice, rising seas, or shifting land. As satellite technology continues to improve, with better resolution and more frequent observations, we gain a clearer view of the processes shaping our planet, over years, decades, and lifetimes.