A suggestion, if I may. The term "warp core" is used a few times in this adventure. If you want to keep an Original Series feel, you may want to consider changing that to a generic "warp engines" or a more '60s technobabble "dilithium chamber."
Risk... risk is our business! That's what this starship is all about... that's why we're aboard her!
I normally do more pulp combat sci-fi so this is going to be something different for me, and I'm looking forward to it.
I've just read through it and this is my current feedback.
I'm going to add in a Scene 5. I think after the Lexington escapes the Klingons the adventure ends too abruptly with too many loose ends. I'm planing a very short scene, no more than ten minutes, where the ship arrives at Dourap IV and finds a Syndicate freighter in orbit, which will answer when hailed. They're surprised to see the Lexington and, realising that their plan has failed, will be keen to get away. While the Syndicate ship is hard to track it can neither outrun or outfight the Lexington. If implicated in the sabotage or if the Lexington attempts to impound their ship they will attempt to bargain. They'll claim it's all been a mix up and that they'll leave and conduct their own investigation into what happened, but will donate the medical supplies they have on board as a sign of good faith. To make the offer more appealing I'm going to say that, since the lost some, their aren't enough medical supplies on board for all of the colonists on Durap by removing the ability to make more medicine while in orbit as it says in the mission brief. If the Lexington attacks anyway they'll dump the medicine and run. The medicine will soon burn up in the atmosphere so the Lexington can either choose to chase the Syndicate ship or beam up the medicine and save all the colonists.
One small alteration to the starting primes too. My players are big scifi fans and while it is from the movies the Motion Picture was a bit iffy with the tech continuity. So instead of starting the mission with the "Wormhole" bit I'll use the excuse that a violent instability of the warp field overloads the control circuits causing the ship to go faster and faster until the engines blow, similar situations happen a couple of times in TOS. Counting up the warp speed should add to the tension as they try and shut down the engines and the ship and systems explode around them under the strain. I'll let the engineer player know that there are safeties in place to prevent this kind of failure from happening, but of course the safeties weren't design to handle sabotage.
John: The use of "warp core" as opposed to "warp reactor" was probably my fault. It might have been introduced in editing, but it was more than likely me and my bad habit of using the terms interchangeably for the last 20 years...which, incidentally, is about how long ago I wrote my last adventure for, well, anything.
Andrew: I'm sorry you don't like the opening, but I can understand. The additional scene you describe is something that I had in mind, but I ran out of word count, and I was more concerned with surviving the encounter. Basically, mea culpa; it does end rather abruptly, but a good GM can fix a lot of problems caused by newb writers....
Geoffrey: The episodic "feel" is just what I was going for; I'm glad you like.
An odd question came up when my players were going through the materials for the Lexington - Why is Security being handled by Helm? I'm not the biggest Trek fan in the group, but even I am pretty sure that Sulu wasn't called on for Security concerns. If anyone on the bridge, I would have thought Checkov handled that sort of thing.
Would it be game-breaking were I to shunt Security off to Navigation/Communications/Sciences?
The logic is that it's something that needs to be overseen from the Bridge, so someone on the Bridge has a responsibility for Security, but the responsibilities covered by the Tactical station in TNG and Voyager (which we know covers Security, because Yar, Worf, and Tuvok are all Chiefs of Security) seem to be spread across the Helm and Navigator consoles (both stations have weapons control). Now, the bridge stations in the playtest are somewhat ad-hoc, created quickly to provide something usable. Depending on the layout of your crew, place the Security Oversight actions on whichever single station seems most fitting (depending on which character seems most suited to oversee Security on the ship).
As it happens, though, Chekov was Chief of Security (in addition to being Navigator) for at least part of his time on the Enterprise and Enterprise-A (mainly in the movies).
Game Development - 2D20 System
System Design - Star Trek Adventures