The National Aeronautics and Space Administration (NASA) anticipates launching Landsat 9, a remote sensing satellite NASA is developing in partnership with the U.S. Geological Survey (USGS), in 2021. Landsat satellites have collected remotely sensed imagery of the Earth's surface at moderate spatial resolution since the launch of Landsat 1 on July 23, 1972. The twolatest satellites in the series, Landsat 7 and Landsat 8, are still in orbit and supplying images and data. Stakeholders use Landsat data in a variety of applications, including land use planning, agriculture, forestry, natural resources management, public safety, homeland security, climate research, and natural disaster management. Landsat data support government, commercial, industrial, civilian, military, and educational users throughout the United States and worldwide. Landsat 7, however, is expected to consume its remaining fuel by summer 2021. To reduce the risk of a gap in Landsat data availability, Landsat 9 development was initiated in March 2015, with a design that is essentially a rebuild of Landsat 8. Once Landsat 9 is operational, it and Landsat 8 will acquire around 1,500 high-quality images of the Earth per day, with a repeat visit every eight days, on average. In 2016, NASA and the Department of the Interior (DOI, the department overseeing the USGS) entered into an interagencyagreement, redefining their long-term collaboration on Landsat through the Sustainable Land Imaging Program and outlining responsibilities for Landsat 9. In this partnership, NASA develops the satellite and the instruments, launches the spacecraft, and checks its performance. Then, the USGS takes over satellite operations and manages and distributes the data from the Earth Resources Observation and Science (EROS) Center in Sioux Falls, SD. NASA Landsat activities are funded under the Earth Science Division of the Science Mission Directorate, and USGS Landsat activities are funded under the National Land Imaging Program in the Land Resources Mission Area. As of FY2020, NASA has spent $517 million on its responsibilities for developing and launching Landsat 9, out of an overall life-cycle cost commitment of $885 million, and the USGS has spent approximately $120 million on Landsat 9 for ground system development.Under a policy initiated in 2008, all Landsat data in USGS archives are available for download free and without restrictions. Researchers estimate that Landsat imagery provided domestic and international users $3.45 billion in benefits in 2017 ($4.18 billion when including cloud vendors), with U.S. users accounting for $2.06 billion of those benefits. Because of Landsat's length of record, availability of data, global coverage, and calibration standards, it serves as the central reference comparison point for many other moderate- and high-resolution optical satellite systems operated by governments and commercial entities. Landsat also has influenced the development of other Earth remote sensing satellites by governments (e.g., the European Space Agency's Copernicus Program Sentinel-2 satellite constellation) and the private sector. A future moderate-resolution mission could differ from previous Landsat satellites by adopting a smaller satellite design, increasing image resolution, increasing the number of images captured per day, reducing the time between images of a givenlocation, sensing a wider variety of optical and infrared frequencies, or making other design changes. Alternativearrangements could include obtaining images from other sources, such as through public-private partnerships or by procuring data from other satellites.