ICESat-2 Laser Technology Readiness Level Evolution

We report on the completion of the space qualification testing program for NASA Goddard Space Flight Center's (GSFC) Ice, Cloud, and Land Elevation Satellite 2 (ICESat-2) program. This paper describes the final performance results of the fully integrated (laser and electronics) flight laser system with an emphasis on the system design evolution from a breadboard demonstration to a fully space-qualified laser system. The 532 nm ICESat-2 laser transmitter generates diffraction limited pulse energies of 1 mJ, pulsewidths of < 1.5 ns, and 10 kHz pulse repetition frequency and has minimum lifetime of 1 trillion pulses on-orbit. A combination of engineering design units and correlated structural thermal optical analysis was used to systematically improve reliability and performance over the operating environment. The laser system qualification and acceptance test programs included electromagnetic interference (EMI), vibration, and thermal vacuum (TVAC) testing. This paper presents key laser performance results and lessons learned on the multi-year laser development to facilitate future space-qualified laser developments, improve reliability, and increase performance.