For spaceborne lidar like the atmospheric backscatter lidar (e.g. ATLID on the ESA EarthCARE mission) highly reliable and efficient laser sources are needed. As pre-development model we realized a Nd:YAG MOPA diode pumped at 100 Hz. With more than 21 % optical-optical efficiency the amplifier based on the InnoSlab design raises the 8 mJ pulse energy from the single frequency rod oscillator to more than 70 mJ. Frequency-tripling leads to more than 25 mJ at 355 nm and a beam quality of M2 < 1.7. The total optical-optical efficiency of more than 7.5 % exceeds the efficiency of comparable current lidar transmitter systems at least by a factor of 2. The laser is designed to cope with diode degradation or failure. Moderate pulse intensities in the InnoSlab amplifier offer excellent possibilities to scale the pulse energy to several 100 mJ in a most reliable and efficient way.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.