Note: Single-source report; awaiting corroboration.
For over 50 years, the Landsat program has primarily captured images of Earth's land and near-shore surfaces during daytime, when sunlight is optimal. Landsat 8 and Landsat 9 now also utilize their ascending orbits to capture nighttime images by special request, marking a shift in their operational use.
The visible spectral bands are typically less effective during the satellites' ascending (night) orbit node, except near the poles during twilight or darkness, where thermal infrared bands provide valuable observations. Using the shortwave infrared bands in the Operational Land Imager and the Thermal Infrared Sensor, Landsat can detect intense heat sources like volcanoes and active fires, and measure surface temperatures from geothermal features to ice.
Dr. Christopher Crawford, Landsat Project Scientist at the USGS Earth Resources Observation and Science Center, notes a growing number of requests for nighttime imaging. This capability supports applications including monitoring active volcanoes, changing ice environments, and the growing wildfire hazards affecting people, infrastructure, and wildlife.
Yellowstone National Park, known for its nearly 10,000 thermal features—including geysers, hot springs, and steam vents—has become an ongoing focus for nighttime observation. Changes in temperature or appearance of these features can be tracked with systematic imaging. After Landsat 9 launched in 2021, doubling revisit frequency to about every eight days, an annual campaign began to capture active volcanoes at night.