NASA has just completed modal testing with the mass simulator on the SLS rocket for Artemis I. With this testing complete, operations can move forward in preparation for rollout to SLC-39B.
There has been a long series of testing in preparation for Artemis I. The most recent of these tests being modal, or vibration testing, in the Vehicle Assembly Building. For these tests, a mass simulator was installed on the SLS rocket that matches the mass of the Orion capsule. These tests started September 24. The various tests that make up modal testing have been completed over the last week. We were able to confirm the successful conclusion of these tests.
With the modal testing complete, the next step is to get the actual Orion capsule on SLS in place of the mass simulator.
We have received confirmation that the mass simulator was removed from SLS earlier tonight. This clears the way for the installation of the Orion Stage Adapter (and its cubesats) and then the Orion capsule.
Source: spaceexplored