In the years following the Excalibur’s mission a problem arose. The Interstellar Alliance was “running out” of Whitestars. They were made with Vorlon technology and since the departure of the Vorlons impossible to rebuild. The Whitestar fleet was slowly crumbling away…
So, a new ship was designed. Similar in size and design, these ships were easy to construct and didn’t use Vorlon technology. They were only slightly less powerful than the original Whitestars. They are Whitestar-Beta ships.
Now the Rangers have a new hope and the Interstellar Alliance has a new fleet.