Which is one of the names of the operational LANDSAT satellites today?

Landsat 9 is the most recent addition to the Landsat program, launched in September 2021, and is currently operational. It provides high-resolution imagery and continues the mission of previous Landsat satellites, which assist in monitoring land use, natural resources, and environmental changes over time. While Landsat 4 and Landsat 5 were significant in their time, they are no longer active; Landsat 4 was decommissioned in 1993 and Landsat 5's mission ended in 2013. Landsat 8, launched in 2013, is still operational, but it is not the most recent. Thus, Landsat 9 is the correct answer, being actively utilized in current operations.