When they finished editing the movie for broadcast, the producers found out that they were actually a few minutes short so the elevator scene with Zack and Lyta was added.
Thirdspace was the first of the TNT movies filmed, but the second one aired, in July 1998. As it was actually filmed in late 1997, Claudia Christian was still part of the Babylon 5 cast at the time. When it was finally aired, Claudia had been replaced in the recurring cast by Tracy Scoggins in the part of Babylon 5 Commander under Sheridan.
The film takes place in April 2261.
The artifact was designed in cooperation with Wayne Douglas Barlow, author of Barlow's Guide to Extraterrestrials.
Leo Rosen was born in 2196.