Two NASA satellites were launched Friday from Vandenberg Air Force Base, Calif., on missions to reveal the inner secrets of clouds and aerosols, tiny particles suspended in the air.

“Clouds are a critical but poorly understood element of our climate,” said Dr. Graeme Stephens, CloudSat principal investigator and a professor at Colorado State University, Fort Collins, Colo. “They shape the energy distribution of our climate system and our planet’s massive water cycle, which delivers the freshwater we drink that sustains all life.”

“With the successful launch of CloudSat and Calipso we take a giant step forward in our ability to study the global atmosphere,” said Calipso Principal Investigator Dr. David Winker of NASA’s Langley Research Center, Hampton, Va. “In the years to come, we expect these missions to spark many new insights into the workings of Earth’s climate and improve our abilities to forecast weather and predict climate change.”