Results from NASA’s Distributed Spacecraft Autonomy Project’s Extended Mission on Starling

The Distributed Spacecraft Autonomy (DSA) experiments on Starling 1.0 marked a significant milestone as the first demonstration of fully autonomous distributed operations on multiple spacecraft. DSA demonstrated the ability to adapt to measurements of Total Electron Content (TEC) and visibility of GPS satellites in a fully distributed autonomous manner. In subsequent experiments, DSA 1.5 focused on improving its science proxy towards a higher-fidelity data product computed at the edge, as well as addressing emergent autonomy needs from Starling 1.0, particularly local autonomy and robust crosslink data transfer.

The purpose of improving the TEC measurement was to demonstrate that high-quality observation data could be generated onboard comparable to data typically produced through ground-based data processing systems. DSA 1.5 was able to incorporate corrections as well as a measure of data quality, both of which are available for the autonomy to incorporate in its decision-making. The autonomy focus of DSA 1.5 was to develop advanced capabilities for distributed space systems by increasing the robustness, resilience and self-sufficiency of spacecraft. While DSA successfully demonstrated autonomous distributed decision-making onboard Starling 1.0, this was accomplished only in software. To demonstrate the ability to command spacecraft hardware subsystems (e.g., crosslink radios) rather than just re-configuring software would greatly increase confidence in onboard autonomy. Similarly, the ability to
safely and autonomously create, and power on and off, the cross-link network during operations will raise mission efficiency by decreasing power consumption, reducing bandwidth, and overall reducing spacecraft mission operation planning. DSA was able to autonomously create, break down, and re-create the crosslink network in response to
changes in the radio frequency (RF) environment—TEC was again used as a proxy for demonstration purposes—as well as orbit position. These reactive autonomy demonstrations were driven by PLEXIL, a NASA-developed plan execution technology flown in space for the first time.

Finally, DSA 1.5 demonstrated the ability to send large files over the Ad-Hoc crosslink network by redelivering failed file segments. This redelivery was based on standard transfer measures in the COMM application and an additional layer of autonomy. DSA 1.5 file delivery (known as LFT) was event-driven instead of pre-scheduled based on absolute
or relative time, thus more robust operations were enabled. LFT was successfully tested on the DSA 1.5 mission extension, during which the spacecraft successfully and repeatedly transferred 10MB files with guarantees on integrity and validity across multiple network interruptions lasting 60 minutes.