Optical Development System life cycle for the ICESat-2 ATLAS instrument

The Optical Development System Lab (ODSL) completed a cycle of prototype testing and engineering model integration models to successfully test out a closed loop optical design. Through this process many lessons have been learned that are being directly applied to flight integration and testing, helping drive down risk, cost, and schedule for the instrument. The ODSL was used to test and understand the functional performance of the transmitter to receiver alignment system concepts. Advanced Topographic Laser Altimeter System (ATLAS) is the instrument being tested by the ODSL and is the main instrument on the ICESat-2 mission. It measures ice elevation by transmitting laser pulses, and collecting the reflection in a telescope. Because the round trip time is used to calculate distance, alignment between the outgoing transmitter beam and the incoming receiver beams are critical. An automated closed loop monitoring control system is currently being tested at the engineering model level to prove out implementation for the final spacecraft. To achieve an error of less than 2 micro-radians, an active deformable mirror was used to correct the lab wave front from the collimated “ground reflection” beam. The lab includes a focal plane assembly set up, a one meter diameter collimator optic, a 0.8 meter flight spare telescope for alignment, and the appropriate flight software to control the transmit beam path. By having a fully integrated system with prototypes and engineering units, lessons were learned before flight designs were finalized. The flight telescope is now ready to be accepted and put through tests that were refined with the ODS lab.