Having achieved their original design sensitivity, the Advanced LIGO gravitational-wave detectors are now observing multiple transients from binary black hole and neutron star collisions every week. For the first time we can now optimize future upgrades and detectors with good guidance on observable signals. Intriguingly, it is feasible to observe binary black hole mergers throughout cosmic times, all the way back to mergers of remnants of the first stars.

This talk will discuss the design work for Cosmic Explorer, which is now underway with NSF funding support. I will highlight some exciting aspects of the detector technology behind Cosmic Explorer, such as its quantum-enhanced readout operating a factor of 3 below the standard quantum limit, and prospects of new crystalline optical coating materials to lower thermal noise. Along the way I will discuss project timeline, challenges, and milestones – both technological and political.

Bio: Stefan Ballmer is a Professor of Physics at Syracuse University. He serves as Instrument Science R&D Coordinator for the Cosmic Explorer project and has been designing, building, and upgrading gravitational-wave detectors for two decades. He received his Ph.D. from the Massachusetts Institute of Technology. sballmer.expressions.syr.edu