Fibertek proposes to design, develop, and test a spaceflight prototype 2051 nm thulium (Tm)-doped fiber amplifier (TDFA) optical master oscillator power amplifier (MOPA) suitable for NASA spaceflight and long duration unmanned aerial vehicle (UAV) missions. The proposed spaceflight TDFA MOPA technology is new, higher efficiency, and not available from any other known source. The amplifer provides high-power, high-performance, and high-reliability continuous wave (CW) operation at 2.051 ?m. NASA and the 2007 National Research Council (NRC) Earth Science Decadal Study1 have identified carbon dioxide (CO2) light detection and ranging (lidar) as a key technology needed to address global change research. The study identifies 2 ?m laser technology as critical to CO2 studies as well as for measuring three dimensional (3D) tropospheric winds. The proposed TDFA technology also supports lidar technology needed to fill Strategic Knowledge Gaps (SKG) for Mars science, aerocapture and planetrary science sensors.