The first pilot created to sell "Star Trek" was titled "The Cage". It starred Jeffrey Hunter as Captain Pike of the USS Enterprise. Although very promising, it was enough to sell NBC on Star Trek, so they asked for another pilot to be made, which was "Where No Man Has Gone Before", with William Shatner as Captain Kirk of the Enterprise. That one did the trick and "Star Trek" became a series that ran for 3 years. In an ingenious bit of economizing and especially story-telling, series creator Gene Roddenberry used "The Cage" in the series only 2-part episode "The Menagerie" (replacing "The Cage" as title).
The department colours were gold for command, beige for engineering and light blue for sciences/medical; and was made of dacron velour. The chest insignia was smaller than the production insignia and bordered in metallic gold. The 1/2" (5/8"?) gold metallic rank braid was worn by most personnel. Only the Captain's yeoman didnt have braid, evident on her tunic as well as her field jacket. A "half-braid" was worn by one bridge crewman. It's designation is unknown. According to Roddenberry, there were no "Enlisted" ranks. Those who served on a starship were the best of the best and thus, were all officers. Thus I can't even guess as to what may have represented what. Enlisted ranks did finally appear in TMP and TWOK. In a series it was used with DS9.
The women also wore pants, and tunics with cowl collars. Their tunics zipped up the back and were fitted. The pants did not appear to have the production pant "sparkle", though they did have a sheen to them. There did not appear to be pockets, though the production pants did have them. Also the faux bell pant cuff didnt seem to flare out as much as the prodcution pant and ended about 6" above the ankle. The boots came up to just below the calf with a buckle top.
It's verified that the brown, metallic gold trimmed jacket worn over the command tunic in the "Pike's Palace" scene is the formal dress jacket for this uniform. It is not known if the colour changed in relation to the other department colours though.
For landing parties, an equipment belt/harness was worn under the field jacket. It could be worn with or without the harness (as was seen with the yeoman
above). It was actually a WWII pistol belt. The harness is known as "suspenders". For the pilot it looked like it was painted white rather than use a
"parade" belt which is white.
With slight changes, the uniforms seen in this pilot were used in the 2nd.