The availability of suitable laser sources is one of the key issues for the development of active optical instruments in future earth observation missions. The main objective of this project is to demonstrate the feasibility of a semiconductor based laser source to be used as a laser transmitter in a Differential- Absorption LIDAR (DIAL) system for the observation and monitoring of greenhouse gases in the atmosphere.The basic building block of the project is a monolithic Master Oscillator Power Amplifier (MOPA) consisting of a frequency stabilized Distributed Feedback (DFB) Master Oscillator (MO) and a multi-section tapered semiconductor Power Amplifier (PA). The required on-, off-line laser wavelengths will be generated in the DFB section and amplified and modulated in the PA section. The device will be fabricated, mounted in a module with the beam forming optics and completed with the stabilization and control electronics. The entire laser source will be designed so that it can be used as the transmitter unit of a Random Modulated CW LIDAR system enabling measurements of the atmospheric CO2 concentration by Integrated-Path Differential-Absorption (IPDA) LIDAR with no signal ambiguity over a distance of 30 km and accuracy in distance determination better than 10 m. As a proof of concept, the CO2 concentration along a 2-3 km test path will be measured on ground and compared with the results provided by an existing DIAL system. For the DIAL test, the receiver unit will be developed in addition.The achievement of the project objectives should provide a substantial progress in the availability of compact, and highly efficient laser sources for the detection and monitoring of greenhouse gases in future earth observation missions and therefore to improve the position of Europe in this field. In a more general context the project will pave the way of using high brightness semiconductor lasers in space applications requiring simultaneously high power, beam quality