PV-91 - Interstellar Travel Without Jump Drives

April 28, 2022 ⌦ MothershipPV-91Game Design

We recently rebooted my home group’s Mothership campaign and I decided to give travel a bigger role in my setting (PV-91). In previous game systems, I felt hyperspace and interstellar travel was either hand-waved or over-simplified.

Seeing as rules for ship building and travel are going to change with the forthcoming Mothership 1e ruleset it seemed like the best solution would be to strip Jump Drives from ships. Without making travel unbearably long, turning every mission into a generational adventure, it seemed the best solution was…

Ring Gates

Cowboy Bebop, 1998

Heavily inspired by things like Cowboy Bebop, The Expanse, and Stargate, I decided to replace jump drives from Mothership’s core (0e) rules with Ring Gates.

Rules as written, Mothership 0e’s Jump Ratings are pretty helpful. They give a great sense of the expansive scale of the universe and how long it takes to travel between worlds and solar systems.

0e Travel Table, (PSG, pg. 27)
Speed Interplanetary Interstellar Intergalactic
10-30 Weeks Years Millenia
31-50 Days Months Decades
51-80 Hours Weeks Years

PV-91 Ring Gate Rules for Mothership 0.5e

Using this as a starting point, I used Drive Ratings to determine:

  1. How many Gates would be at a Jump Point?
  2. What distance do the Gates cover? and
  3. How long does it take?
Rev. 1.0

These rules are somewhat in flux as we play and I see what makes sense and what works at the table. For now PV-91 is locked at a Jump 5 Tech Rating.

PV-91 Ring Gate Table
Ring Count Distance Duration Die
1 Interplanetary Weeks d10
2 Interplanetary Days d10
3 Interplanetary Hours d20
4 Interstellar Months d10
5 Interstellar Weeks d5
6 Interstellar Days d10
7 Interstellar Hours d20
8 Intergalactic Years d20+
9 Intergalactic Months d20

Gate System Notes and Procedures

As the crew no longer can jump whenever and from whenever they like, Ring Gates location carries an increased value. This is something I plan to use in the near future for strategic faction play and as adventure hooks. I love attacking the character sheet when designing and I plan to use Ring Gates the same way.

Interstellar Technology

Using Ring Gates also presents an opportunity to use technology as a plot point. Running through an adventure I wrote for an upcoming release (this isn’t a spoiler) a derelict ship has a massive hole in the center which originally housed an ancient Jump Drive.

As the PCs and Characters both know that Ring Gates are the established, universal technology, they immediately were filled with questions.

It also give me the opportunity to use new tech as future adventures. “A new mysterious megacorp wants to hire you to test their new ring system or deliver a gate system to a previously unexplored region.” Pretty solid adventure hook with a high risk, high reward to pay off the millions of credits of debt they owe on their ship.


One problem that Ring Gates presents is in the reality of hyperspace. Much like a VPN or data encryption, there’s not a shortcut or off ramp to get out early. Once you’re in a jump, you’re stuck until you pass through the gates at the receiving end.

This first came up in a playthrough Sean’s Board With Life Actual Play. It was probably one of the best adventures we’ve ever done in Mothership (using the WIP 1e rules) but the new nature of Hyperspace presented some challenges.

Spoilers for the Board With Life AP ahead

After the crew had docked with Moser’s ship from an alternate reality, the de facto pilot asked if they could leave hyperspace at least twice.

While this might have been a convenient solution for the crew I fell back on the established tech of the Ring Gates to keep verisimilitude. In a way, this also establishes a canonical reason for why Moser would be stuck in hyperspace in the first place.

End of Spoilers

I was worried that this might have felt overly restrictive but as we discussed the session in our post-op2 everyone agreed that it made sense within the scope of how Ring Gates operated. As that tech was established in our zero session, the pilot was clarifying how the technology worked.

So even though the boundaries established by this type of FTL could be a barrier, it seemed like one we could still work with and even use to frame our style of play. Which allowed me to focus on another hyperspace trope…


I love the concept of requiring Human/Organic life be in cryo for the duration jumps but I haven’t quite worked out why. Mothership 0e notes that it’s a habit because “those who stay awake during hyper sleep have reported strange and conflicting stories about the experience” (Player’s Survival Guide, 27.2).

It’s entirely possible it’s a myth or old wives tale tale left over from the days of early jump tests and ship-based testing. With the advent of Ring Gates, the mind bending effects of FTL might be a thing of the past that most spacers aren’t willing to take chance on.

Ideally, being awake during jumps would have a mechanical implication: hallucinations, mathematical epiphanies beyond understanding. I haven’t quite figured out what that would look like. I think I’ll need a cryo-nap first.

  1. Fuel is probably the easiest to track at the table.↩︎

  2. This isn’t a formal practice we have, just a habit of years of playing together. Talking about the game, how it went, and highlighting our favorite, stand-out moments.↩︎