Possibility of spaceborne lidar application to the exploration of circumterrestrial space has been analyzed. The optical characteristics of the principal light scattering constituents including molecules and atomic gases, free electrons, aerosols, and space debris have been evaluated at altitudes of 100—500 km above the Earth's surface. The power of lidar return signals has been estimated based on the laser sensing and laser detection and ranging equations. It is shown that spaceborne lidar with modern technical characteristics is capable of reliable reception of signals from disperse components of circumterrestrial space at distances of several hundred meters from a spacecraft. Pieces of space debris can be detected by a lidar at distances from a few kilometers to several tens of kilometers.