The First Decade of Breakthrough Listen

Breakthrough Listen (BL) launched in July 2015 with a 10-year, $100M commitment from the Breakthrough Prize Foundation and is described as the most comprehensive search for technosignatures ever conducted. This paper reviews the program's first decade from the facilities and instrumentation perspective, covering its digital backends and data recorders, signal-processing pipelines, data archive, and observatory partnerships, and organizes the decade into three architectural eras.

In Generation 1 (2016–2019), BL deployed packetized raw-voltage wideband recorders on the 100-m Green Bank Telescope and the 64-m Parkes telescope, enabling targeted surveys of thousands of nearby stars across ~0.7–8 GHz. During a network-expansion phase (2020–2023), BL extended its instrumentation to partner facilities including the Sardinia Radio Telescope and international LOFAR stations, and developed verification frameworks that proved essential when the program's highest-profile signal candidates emerged.

Since 2023, BL has operated in a fully commensal era: Ethernet-based, commodity-GPU backends riding on routine observatory operations. These include COSMIC at the Karl G. Jansky VLA, a revived Allen Telescope Array with deployed real-time deep-learning pipelines, and an autonomous multi-beam commensal survey at MeerKAT (BLUSE; more than 1.2 million pointings since mid-2022). Over the decade, capturing data at ever higher rates forced a systematic approach to compression and archiving, with the storage estate growing to ~42 PB of capacity (~31 PB in use) across seven systems on four continents by March 2026.

The paper concludes with engineering lessons—commodity hardware over bespoke hardware, open data as a first-class requirement, commensal science as backend validation, and verification frameworks built before they are needed—and with the outlook for SKA-era commensal technosignature science.