Check out the SORCE twitter feed for updates on the Optical Clock:
https://twitter.com/opticalclock
More information on the project can be found here:
https://sorce.home.blog/
Stratospheric Optical Rubidium Clock Experiment
Grad students Shira Jackson and Kristen Cote successfully launched and remotely operated an atomic clock on a high altitude balloon, over the Labour Day Weekend. This atomic clock used an optical transition in rubidium atoms.
