Isaacson Award Talk: From Table Top Experiments to LIGO’s Gravitational-Wave Observatories

The proposal to build "A Laser Interferometer Gravitational-wave Observatory (LIGO)", submitted to the U.S. National Science Foundation (NSF) in 1989, described an evolutionary development path to observe gravitational-wave events routinely and to exploit these observations as a new tool for astronomy and physics. Many decades of NSF support for LIGO nurtured transformational change. In 1989, several dozen people were exploring techniques for gravitational-wave detection in small-scale laboratory experiments worldwide. Today, LIGO's kilometer-scale observatory facilities and detectors operate as part of an international gravitational-wave astronomy network, serving a community of thousands contributing to gravitational-wave astronomy. I will compare some highlights of the path envisioned in 1989 to the path followed to move from small-scale laboratory experiments to initial kilometer-scale observatory operations, including technical, human and societal challenges. The interplay between small-scale experiments and experience in observatory commissioning and operations continues to inform upgrades to detection capabilities and the possible paths toward the future.