Lidar in space

The lidar (laser radar) technique of remotely observing atmospheric structure and composition is ready for use on a space vehicle. The Spacelab program provides an ideal facility for initiating and exploring this concept, since it makes development possible on a short-trip minimum-investment basis. The goals, philosophy, and rationale of a proposed program to accomplish the first use of lidar in space are described, and details are provided of the specific observations proposed and of the necessary instrumentation. Using a solid-state neodymium laser frequency-doubled to drive a tunable doubled dye laser, energy could be transmitted in a range of wavelengths. With simple wavelength-discriminating photometric detectors the system could be used to detect returns from particles (cloud and dust) or Na atoms or Mg(+) ions.