NASA is set to announce its next generation of Earth-observing satellites. As soon as this month, it will lay out plans for a multibillion-dollar set of missions that will launch later this decade. This "Earth system observatory" will offer insights into two long-standing wild cards of climate change—clouds and aerosols—while providing new details about the planet's changing surface. The satellite fleets also mark a revival for NASA's earth science, which has languished over the past decade compared with exploration of Mars and other planets. The satellite missions have been in planning for several years, but received a boost of interest from the Biden administration. The largest mission will involve multiple satellites in two different orbits, armed with radar and lasers capable of measuring clouds and atmospheric particles down to near Earth's surface. Scientists hope the satellites will clarify how clouds could respond to global warming, while also delineating the degree that human pollution has altered clouds' abundance. Other missions will use a "hyperspectral" imaging spectrometer—a molecular mapping system—and an infrared radiometer to measure the chemistry and changing heat of the planet's surface, while a final mission will continue measurements of Earth's changing gravitational distribution, allowing fine measurements of melting ice caps.