File:Contrails over the Mid-Atlantic United States (MODIS).jpg

English: The skies over the Mid-Atlantic region of the United States were crisscrossed with contrails on November 6, 2023, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this true-color image. The long, thin lines of cloud left behind by high-flying aircraft (contrails) streak the skies over southern New Jersey, the Delaware Bay, Delaware, the Chesapeake Bay, Maryland, the District of Columbia, and Northern Virginia, all of which lie below busy aircraft routes. The contrails mix with a band of cloud that overhangs the District of Columbia.

Contrails form when aircraft operate in cold temperatures at high altitudes. The water vapor in their exhaust cools and condenses, and when it interacts with either the soot or other particles in the air, it forms ice crystals. Those contrails can linger in the upper atmosphere for hours, producing localized temperature impacts. Over time, contrails can impact climate change.

Alternative fuels, including sustainable aviation fuels, can release fewer soot particles than typical jet engine fuel. Research models find that alternative fuels may result in fewer crystals, and the ones that do form will be larger, falling and melting in the warmer air below, thus reducing contrails’ environmental impact.

NASA researchers are collaborating with Boeing and other partners to collect data to see how new, greener aviation fuels can help reduce the problem. In October, NASA and Boeing conducted a contrail research campaign in Washington State. NASA’s DC-8 aircraft followed behind one of Boeing’s ecoDemonstrator Explorer aircraft, which conducted test flights switching between tanks filled with either 100% sustainable aviation fuel or a low-sulfur version of conventional jet fuel. NASA’s DC-8 measured emissions and contrail ice formation from each type of fuel.

“Contrails are believed to be a major source of pollution,” said Rich Moore, a research physical scientist in NASA’s Langley Aerosol Research Group Experiment and principal investigator for the campaign. “With this flight campaign, we’re looking not so much at correcting contrails, but at preventing them.”

Results of the research are expected to be published within a year, and the data will be publicly available worldwide.