Ever since the May 18 eruption of Mount St. Helens, the National Aeronautics and Space Administration has been working closely with scientists from universities and government agencies to assess the impact of the explosive geologic event. Instrument-laden NASA aircraft, balloons, and spacecraft all have contributed important data. Mount St. Helens is undoubtedly the best documented volcanic eruption in history.

Shortly after the eruption began, a high-flying U-2 aircraft from NASA's Ames Research Center, Mountain View, California, was dispatched to sample the air within 185 km (100 miles) of the volcano. Back on the ground, scientists working with NASA's Aerosol Climatic Effects Program used the data that was collected on particulate matter to study the potential climatic effects of the ash blown into the upper reaches of the atmosphere by the violent explosion. Repeated U-2 flights, days after the eruption, continued to track the volcanic dust cloud and to photograph the devastation wrought upon the mountain by its self-destructive blast.