Vulcan is on the pad. Gizmodo has a good primer on the new rocket:

Vulcan integrates design elements from both ULA’s Atlas V and Delta IV rockets and is poised to be their successor. It can deliver payloads to a wide range of target destinations, from low Earth orbit (LEO) and geosynchronous orbit (GEO) through to lunar and deep space exploration missions. It’s a highly versatile rocket, equipped with the capability to launch multiple payloads simultaneously.

Launch is scheduled for Jan. 8, 2024 at 2:18 a.m. ET. Check the ULA site for livestream info and launch updates.