NASA's PACE satellite launched in early February 2024, to study the health of the Earth's oceans, land, and atmosphere. As data has been collected, the next step is to validate the measurements provided by this data. For the entire month of September, "the mission’s biggest validation campaign, called PACE Postlaunch Airborne eXperiment (PACE-PAX)" will consist of scientists taking measurements from ships and aircraft from three different locations in California. Read more about the PACE-PAX mission in this NASA Goddard article.