A Doppler lidar can measure wind profiles in the atmosphere with excellent accuracy. Invisible atmospheric inhomogeneities such as aircraft wake vortices can be detected and tracked. Lidars are proposed for spaceborne application. The backscatter lidar technology experiment (LITE) was successfully tested in space in 1994. A Doppler lidar in space can give both wind and backscatter information. Examples of proposed spaceborne lidars are discussed.