ABSTRACT
The Advanced Space Carbon and Climate Observation of Planet Earth (A-SCOPE) mission, a candidate for the next generation of European Space Agency Earth Explorer Core Missions, aims at measuring CO(2) concentration from space with an integrated path differential absorption (IPDA) lidar. We report the optimization of the lidar instrument operating wavelengths, building on two performance models developed to assess measurement random errors from the instrument, as well as knowledge errors on geophysical and spectral parameters required for the measurement processing. A promising approach to decrease sensitivity to water vapor errors by 1 order of magnitude is reported and illustrated. The presented methods are applicable for any airborne or spaceborne IPDA lidar.
ABSTRACT
The adequacy of commercial quasi-continuous high-power laser diode arrays (HPLDAs) as pump sources for spaceborne lasers has been assessed by endurance tests up to 3 x 10(9) shots under various stress conditions, vacuum operation up to 0.36 x 10(9) shots, and proton radiation tests. Observations of the evolution of the electro-optic parameters and of the near-field patterns of the HPLDAs during endurance tests have revealed that some diode bars could reach the required lifetime of a multibillion shots, suggesting how to build long lifetime HPLDAs by proper selection of the diode bars. The robustness of the HPLDAs against the proton environment experienced in a typical low Earth orbit has been checked. Finally, high-power laser diode arrays have been operated under vacuum, showing a behavior similar to that of HPLDAs operating in atmospheric conditions.
