I’d pick Traveller for budgeting psychic power, or Dark Heresy for risking harm with every use. In Traveller, spending PSI can make later attempts harder. In Dark Heresy, rolling three psychic dice gives you a 27.1% chance of triggering Psychic Phenomena - even if your power works.
I compare four costs: resources, recovery time, falling reliability, and fallout. The choice comes down to whether your group prefers planning around limits or dealing with danger that can affect everyone.
Quick Comparison
| Cost | Traveller - Mongoose Second Edition, Update 2022 | Dark Heresy - First Edition |
|---|---|---|
| Resources | Successful powers spend listed PSI; failed attempts cost 1 PSI. | No power-point pool; attempts cost an action and carry risk. |
| Recovery | Regain 1 PSI per hour after a three-hour wait without use. | No psychic pool to refill; harm may require more than rest. |
| Reliability | Lower PSI can make later checks harder. | More dice help powers work but increase the chance of Phenomena. |
| Fallout | Usually failed activation and lost PSI. | Even success can bring Perils of the Warp and harm allies. |
For my table, I’d settle one question first: Do we want power that runs low, or power that can go wrong?
Traveller vs Dark Heresy: The Cost of Psychic Powers
Traveller: Part 7 - Psionics
1. Traveller - Mongoose Second Edition, Core Rulebook Update 2022
In Traveller, gaining psionic ability costs more than using it. You’ll need referee approval, testing, and training. Testing generally takes two weeks and costs at least Cr5,000. Training takes four months and costs Cr100,000.
Immediate cost
Each successful talent spends its listed PSI cost. Failed attempts still cost 1 PSI, so keep some points in reserve for your key powers.
Recovery time
PSI returns at 1 point per hour, beginning three hours after your last use. Use it again, and that three-hour wait starts over.
Reliability under repeated use
Checks use your current PSI modifier. As your PSI drops, later attempts become harder.
Consequences of failure
Traveller focuses on depletion rather than backlash: failure drains PSI instead of causing psychic harm. Choose it for useful powers held in check by resource management, not catastrophic risk. Dark Heresy shifts that tension from scarcity to danger.
2. Dark Heresy - First Edition
Where Traveller drains a resource, Dark Heresy tests your control.
Immediate cost
You spend an action, not power points. Roll up to your Psy Rating in d10s, then add the total to your Willpower Bonus and modifiers. You must meet or exceed the power’s Threshold. Higher-tier powers also require a minimum Psy Rating - a good roll won’t let you bypass that requirement.
Recovery time
Psy Rating isn’t spent, so you can keep attempting powers. However, errata limits you to one Focus Power action per round. The cost comes from Warp risk, not a dwindling resource pool.
Reliability under repeated use
Your dice pool stays the same, but each attempt brings another chance of Psychic Phenomena. More dice make it easier to reach the Threshold. They also increase the chance of rolling at least one 9: 10% with one die, 19% with two, and 27.1% with three.
If your Willpower Bonus is already close to the Threshold, rolling fewer dice can reduce the risk while still giving you a chance to succeed.
Consequences of lost control
Missing the Threshold and triggering Psychic Phenomena are separate outcomes. A manifestation die showing 9 can trigger Phenomena even if the power succeeds. High Phenomena results can escalate to Perils of the Warp, with consequences that include daemon attacks or the psyker being swallowed by the Warp.
How Psychic Costs Affect Play
The rules above set the price of psychic power in each game: points, time, reliability, or fallout. Those costs shape whether psychic scenes feel like rationing, gambling, or both - and influence the campaign trade-offs that follow.
Immediate Cost: Spend Points or Risk Fallout
Traveller charges points for power; Dark Heresy puts risk on the table. In Traveller, each attempt draws from PSI. In Dark Heresy, activation and dangerous fallout are separate possibilities.
Recovery Time: Restore Points or Deal With Harm
Recovery sets the pace. Traveller requires pauses to restore PSI, while Dark Heresy leaves players to deal with harm that rest alone may not resolve.
Reliability Loss: Lower Modifiers or More Exposure
Traveller gives players a reason to conserve PSI: spending it can weaken later checks. Dark Heresy instead lets players trade better activation odds for more exposure to danger.
Forced Consequences: When Success Still Causes Harm
Traveller usually makes players pay through depletion. Dark Heresy can make even a successful power dangerous, with collateral harm to the psyker or others.
| Cost type | Traveller - Mongoose Second Edition, Core Rulebook Update 2022 | Dark Heresy - First Edition |
|---|---|---|
| Immediate cost | Successful talents spend their listed PSI cost; failed attempts cost 1 PSI. Players must budget resources for every attempt. | No universal power-point cost. Roll manifestation dice to meet the Threshold; failure and dangerous fallout are separate possibilities. |
| Recovery time | Recovery starts three hours after the last use, at 1 PSI per hour. Using a power again restarts the wait, so planned pauses help. | No spent psychic pool to restore. Wounds, fatigue, and lasting consequences each need recovery or resolution; rest alone may not resolve them. |
| Reliability loss | Falling PSI can lower later check modifiers. Using power now can mean less capability later. | Repeated use does not deplete the dice pool, but each use adds exposure. More dice improve success odds while increasing the chance of triggering Phenomena. |
| Forced consequences | Ordinary failure means failed activation and PSI loss, not automatic psychic backlash. Individual talents may specify hazards. | Rolled 9s trigger Phenomena; results of 75 or higher escalate to Perils. Even success can endanger the psyker, nearby allies, or the scene. |
Campaign Benefits and Trade-offs
These mechanical costs shape campaign pacing, not just individual rolls. Traveller rewards planning beyond the next power use. Visible PSI reserves make each casting a choice between an immediate gain and fewer options later. When downtime is limited, recovery adds pressure to the mission.
Work recovery into travel, watches, or downtime. Keep depleted characters involved through skills, equipment, and social encounters. The goal is to slow power use - not stall the campaign. Dark Heresy creates a different pace by putting uncertainty, rather than resource management, at the center of play.
Dark Heresy makes psychic risk a concern for the whole table. Before play, agree on expectations for uncertainty and consequences that affect everyone. Shared risk supports horror, but players who prefer tightly planned missions may find the disruption frustrating.
Here’s how those trade-offs compare.
| Game | Advantages | Trade-offs | Best-fit campaign tension |
|---|---|---|---|
| Traveller - Mongoose Second Edition, Core Rulebook Update 2022 | Visible reserves help players budget power and choose when to use it. | Heavy use weakens later options and slows operations. | Scarcity, preparation, exploration, and mission logistics. |
| Dark Heresy - First Edition | Even success brings suspense and complications. | Fallout can disrupt plans, injure allies, or permanently harm the psyker. | Horror, investigation, corruption, and crisis management. |
For Dark Heresy, use the published consequences as written. State the objective and any group-wide stakes before the roll. After fallout, give everyone a way to respond: contain the disturbance, aid an ally, or retreat.
Choose Between Scarcity and Risk
After weighing the costs above, choose Traveller if you want psychic power to reward careful budgeting. PSI is limited and recovers slowly, so every use matters. The cost comes down to scarcity and recovery.
Choose Dark Heresy First Edition if you want psychic power to remain dangerous with every use. Pushing for success increases your exposure to Psychic Phenomena, and even a successful attempt can cause collateral harm. Here, the cost is escalation and fallout.
FAQs
How can I stay useful when my PSI runs low?
When PSI runs low, save powers for moments that change the outcome. In Traveller-style systems, spend scarce Psionic Strength on tasks your team can’t handle any other way. Avoid fights so you can still take damage and stay effective.
In high-risk systems, disengage or stabilize as panic or stress builds, before spending more resources. Plan time to rest and move into safer positions so you’re not forced to use powers under pressure.
How risky is repeated psychic use in Dark Heresy?
Repeated use of psychic powers in Dark Heresy is high-risk: it can trigger dangerous psychic phenomena and Perils of the Warp. Powers don’t just consume resources. Continuing to push them increases the chance of severe, potentially harmful outcomes.
How can our group handle psychic collateral damage?
Shared resource pools promote teamwork and push players to balance the cost of psychic powers against the group’s stability. Tension tracks or stress meters show rising danger and psychic strain before a crisis hits. When a psychic check fails, resistance rolls or spending stress and other resources can soften the fallout or change how it plays out.
