STA Dev Blog 003: A Guide to Star Trek Adventures

By Nathan Dowdell, 2d20 System Developer

Basic Rules: Momentum and Threat

At the heart of the gameplay of Star Trek Adventures are two resources which will be generated and spent during play. These are Momentum and Threat.

  • Momentum represents the opportunities and advantages that come from success and cooperation.
  • Threat represents the unknown perils that await in space, the unforeseen challenges that will arise to meet you, and the uncertain consequences of action.

All tasks can generate Momentum, but only a group of player characters can save Momentum for later use. Only the gamemaster has Threat, but NPCs can spend Momentum to add to Threat, and player characters can add to Threat in some ways.


When you succeed at a task, any successes you score beyond the minimum needed to match the Difficulty become Momentum: each excess success becomes one point of Momentum. When you generate Momentum in this way, you have two choices: spend or save.

Any Momentum you spend right there and then can be used to improve the outcome of the task you just succeeded at. This can be done in a variety of ways, and the rulebook explains numerous different options, but one of the most common is to Obtain Information, where each point of Momentum spent lets you ask one question about the situation and get a true answer. You may spend Momentum like this one at a time, seeing the effect before you choose whether to spend the next point; with Obtain Information, that would let you ask a question, and hear the answer before you decide whether you have more questions or if you want to save the rest of your Momentum.

Some Momentum options are listed as Repeatable. These can be used as many times as you want. Other Momentum spends can only be used once per task, or once per round in a conflict (which we’ll discuss in a future article).

Any Momentum you save goes into a group pool, and up to six points can be saved in total. This pool of Momentum can be used or added to by any member of your group – it is a shared resource, so your successes can benefit your allies, and their successes can benefit you. A Starfleet officer knows that cooperation makes a crew greater than the sum of its members, and a Klingon warrior is only as strong as those who stand side-by-side with them.

With most uses for Momentum, you can only spend saved Momentum in situations where you could already spend Momentum – immediately after a successful task – but some Momentum uses are listed as Immediate. These can be paid for at any time, spending directly out of the group pool, or even paid for by adding directly to Threat. The most common examples of this is buying additional d20s for a task, or paying to increase the Difficulty of an opponent’s action.

Momentum needs to be maintained, however. At the end of each scene, the group pool loses a point of Momentum, as the passage of time allows opportunities to pass and the urgency of action fades a little. Momentum is there to be used, and if you don’t use it, it’ll fade away.

Using Momentum

It’s a common instinct for new players to hoard Momentum, saving it up for that situation where they really need it. This isn’t necessarily wrong, as saving a couple of points for an emergency can make all the difference, but it’s useful to temper that instinct. Momentum can be generated quite easily, and spending Momentum to buy extra dice can often result in some of that Momentum coming back, especially if the character is highly skilled.

In addition to being easy to generate, Momentum will fade if not used, and there’s a maximum amount you can save, so hoarding Momentum is more likely to result in it being wasted. A proactive approach to using Momentum helps avoid that wastage.


Threat is all the things that could go wrong when exploring the unknown or facing a challenging situation.

In many ways, Threat is a lot like Momentum in how it is used during play: the gamemaster spends Threat to benefit NPCs in the same ways that players can spend Momentum to boost their player characters, and NPCs can save their unspent Momentum as Threat in a similar way to the player characters saving Momentum.

But there are a number of key differences.

Adding to Threat

While the gamemaster will begin each session with a small amount of Threat (normally 2 per player character), that supply is unlikely to last long. However, there are a number of ways that Threat can grow during the course of play:

  • Complications suffered by the player characters may result in 2 points being added to Threat instead of some other immediate problem occurring – in essence, this trades an immediate problem for a later one.
  • Player characters can pay for Immediate Momentum options, such as buying bonus d20s, by adding to Threat instead of spending Momentum, representing the character taking a risk to gain a benefit.
  • NPCs may spend Momentum from their tasks to add to Threat, mirroring how player characters can save their Momentum.
  • Some actions, such as using lethal force, or entering a situation with high-powered weapons such as rifles, can add to Threat, escalating a situation and making things more dangerous and unpredictable.

There can be other situations which add to Threat as well, but the four above are the most common.

Spending Threat

While Threat can be spent in the same ways Momentum can be used, those aren’t the only ways the gamemaster can use Threat. Ideally, the gamemaster should be using Threat in small quantities fairly regularly throughout each scene, rather than allowing it to build and build. The gamemaster should manage the Threat pool – spending it down or saving it up accordingly – to reflect the desired level of tension and peril in the adventure: lots of Threat signals a difficult challenge ahead, while little Threat means fewer things going wrong.

  • Threat can be used by NPCs in all the ways Momentum can be used by the player characters.
  • Some NPCs may have options or abilities which require spending Threat, such as equipping an enemy with a disruptor rifle instead of a disruptor pistol.
  • The gamemaster may create a complication for the players by spending 2 Threat. This complication should make sense for the situation, and be something that could logically happen.
  • The gamemaster can spend Threat to introduce additional opponents into a scene: enemy troops beaming down from their ship or responding to a disturbance, an enemy vessel arriving suddenly or decloaking.
  • The gamemaster may also spend Threat for story reasons, introducing new problems and challenges to overcome.

Players and Threat

While we’ll deal with interesting ways for the gamemaster to use and manage Threat in a later article, it’s useful to approach a common concern with Threat: how players interact with it.

Players, especially new ones, are often unduly worried about Threat building up, fearful of what the gamemaster could do with it. This is especially the case in groups where the gamemaster doesn’t spent Threat often, as the pool will build and build, deepening the fear of what it’s building towards. In truth, a point of Threat is no more menacing than a point of Momentum, and often as useful for the players as the gamemaster.

If your group is low on Momentum, there’s nothing to stop you from buying a die or two by adding to Threat, boosting your odds of succeeding… and better yet, if you do succeed, that Threat might produce Momentum for you to use so that you don’t need to add to Threat so much later. Similarly, adding to Threat might give you an edge in the short-term which is necessary to overcome a particularly imposing challenge or deadly foe. Using Threat occasionally and decisively can mean victory against impossible odds, and that kind of calculated risk-taking is entirely in keeping with the traditions of Starfleet and the Klingon Empire: as James Kirk once remarked, “Risk is our business.” 

Thanks for reading this article, and thank you for your interest and support of Star Trek Adventures! Keep your frequencies open for additional STA development blogs on a wide variety of game-related topics in the coming months.

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