"This segment begins a multi-episode arc that follows the NX-01's journey into the Delphic Expanse…” seemingly taking a leaf out of the DS9 book, which often dealt with arc stories such as the Dominion War. “With a nine-day shooting schedule under the direction of Allan Kroeker, "Xindi" gave the various production departments some of their biggest challenges since the series pilot "Broken Bow."

As the title suggests, the episode centres on the mysterious Xindi, creating a great deal of work not only for Michael Westmore’s make-up team, but also the special FX department. “We learn in this episode that there are actually several sentient species of Xindi, all collaborating in the campaign against humanity, including "Xindi-Reptilians," "Xindi-Sloths" and the simpler "Xindi-Humanoids." We'll also be seeing "Xindi-Insectoids" and "Xindi-Aquatics," but they'll be computer generated by Dan Curry's and Ronald B. Moore's visual effects team.”

There was plenty of work to spread round all areas of the production team, including Herman Zimmerman with the production design. “The script calls for [a Xindi] complex to be filled with a murky blue haze, and blue residue caking the walls (the mined substance is called "trellium"). So the production crew not only dressed the mine sets with painted rocks and quartz crystals, but also brought in bags and bags of blue-dyed Styrofoam. A blue-tinted smoke filled the sets during the shooting, and the actors involved in those scenes including Scott Bakula were lucky enough to be smeared with blue dust.”

Finally, details of the new marine style characters becomes clearer, as details of character and actor names as well as the team’s title are revealed for the first time. “A significant new element in the show this season is the presence of a military contingent, as mentioned in "The Expanse." These soldiers are referred to as MACOs, standing for "Military Assault Command Operations." The team is led by a notable actor for STAR TREK fans; Steven Culp plays 'Major Hayes' known to many fans by now as Commander Riker’s replacement as First Officer, Commander Martin Madden in Star Trek Nemesis.

There are a contingent of other guest and recurring roles, filled by many Trek alumni:

• Nathan Anderson ('Namon' in VOYAGER’S “Nemesis”) plays 'Sergeant Kempe'
• Daniel Dae Kim ('Gotana-Retz' VOYAGER’S "Blink of an Eye") plays 'Corporal Chang'.
• Richard Lineback
• Stephen McHattie
• Randy Oglesby
• Scott MacDonald, Rick Worthy and Tucker Smallwood.

You can read more about the production details here.