Operation of the NRL-SDA optical communication terminal testbed

The US Naval Research Laboratory (NRL) has, since early 2023, been operating an optical communication interoperability testbed for the Space Development Agency’s (SDA) Tranche one program. This testbed evaluates pointing, acquisition, and tracking capabilities, as well as data transport performance. The testbed has been used to test Optical Communication Terminals (OCT) from four different vendors as well the modem for a ground station. These OCTs are tested both against a government reference modem and each other to ensure compatibility between all the vendor implementations of the SDA OCT standard. Throughout execution of OIT testing, multiple vendor OCT inconsistencies and shortcomings have been identified and resolved, thus significantly reducing risk ahead of delivery of OCTs for integration on a spacecraft. Without the NRL OIT testbed, identification and root cause of OCT shortcomings against the OCT standard would be challenging and expensive to resolve once the OCTs are in orbit. This work will discuss how these issues are detected, the resolution process between NRL, SDA, and the OCT vendor, and the general process for multivendor optical interoperability testing.