“You’re using Star Wars and physics in the same sentence….”

I had an unusual exchange on Twitter the other day. Unusual because I (frankly) was a bit of a jerk to @beltalowda_ and unusual because I let popular sci-fi get under my skin.

First, the exchange:

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I cut off my response because I was a bit of a jerk and talked down to @beltalowda_ (hey, if you’re reading this, sorry!).

The main point I was trying to make (on Twitter? I must be crazy!) is that science fiction and science fact don’t mix well, especially in the realm of gaming. Star Wars is nominally science fiction (I would argue it is more science fantasy but that is another, fruitless, discussion) and the games related to the franchise reflect that origin. Star Wars: X-Wing Miniatures Game today is ranked as the #63 game overall on BoardGameGeek as well as the #7 Customizable Game (interestingly, Star Wars: X-Wing Miniatures – The Force Awakens Core Set is ranked #4 in the Customizable Game category). These games use what gamers often refer to as “cinematic movement,” i.e. they fly about in space like airplanes. This is far different from what space combat will likely look like. Atomic Rockets, IMNSHO one of the best sites on the internet, devotes a whole section to Space War and what is closer to reality. For me, one of the hallmarks of a hard sci-fi game is the use of vector movement, ala (loosely) The Expanse.

Overall, The Expanse is better at hard sci-fi than many shows but even here there is a good deal of “handwavium” involved. Scott Manley on YouTube has made one of the better explanations so far:

My personal gaming experience has shown the same conflict between hard and popular sci-fi. I have bounced between hard (realistic?) sci-fi and more cinematic portrayals. Here is a list of a few games in my collection and how they looked at space combat:

Finding the right balance between popular sci-fi and hard sci-fi gaming is tricky. For myself, games like Star Fleet Battles and its derivatives are fun because of the theme since when playing these games I am choosing theme over mechanics. Some of the more hard sci-fi games are fun with a bit or realism thrown in (like Mayday) but some go too far (Squadron Strike: Traveller) where the fun has a hard time overcoming the difficulty of rules and play.

The upside of all this is that the gaming scene is broad enough that either preference, cinematic or vector, can be accommodated. It’s a matter of choice, and the game industry is healthy enough to give us that choice. Even if I am choosing not to play.

Hattip to @TableTopBill who commented on my tweet with the title of this post.

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Random Gaming Thoughts (Good & Bad) on the First Weekend in May 2018

Sort of a hodgepodge post today. More a collection of random gaming (and beyond) thoughts than anything in particular.

Travel Gaming – Took along several solo games to play while on the road this week. Only got to play one – Merrill’s Marauders: Commandos in Burma 1943-1944 (Decision Games, 2016).

RPG Gaming – Gypsy Knight Games had their May the Fourth Sale going on so I picked up the new Manhunters: Bounty Hunters in the Clement Sector (2018). This has a very Classic Traveller RPG and Firefly-like vibe to it. I also picked up Uranium Fever: Asteroid Mining Rules for the Cepheus Engine (Stellagama Publishing, 2018). I really need to get back into RPGs. I am still awaiting my now-delayed Cortex Prime: A Multi-Genre Roleplaying Game by Cam Banks from Kickstarter. As much as I like Fantasy Flight Games Star Wars: Edge of the Empire RPG I probably should pick up the “generic” Genesys RPG.

Speaking of Star Wars – I hear that FFG is going to be publishing X-Wing Second Edition. This one will be app-enabled.

I think I’ll wait for Ares Games and their Battlestar Galactica version instead.

Speaking of Kickstarter – In April I backed No Motherland Without, a 2-player card game about North Korea since 1953. It really looked interesting. I had really high hopes. It was cancelled – for all the right reasons I am sure. I hope they come back and try again, maybe with a stronger publicity campaign. Personally I watched The Players Aid review and was sold:

Veterans in The Expanse (very mild spoilers for S3E4) – I like The Expanse TV series but one line got me going last week. Alex states he has done his time and is an honorably discharged veteran. His implication is that he is special. As an honorably discharged veteran myself I resent this attitude. Unfortunately, I see it everyday – too many veterans who believe that since they served they have a special privilege above “mere” civilians. They grouse when a place does not offer a veterans discount or the like. Being a veteran does not make you a special citizen. This is not the world of Robert Heinlein’s Starship Troopers (the book, not the horrible movie) where only veterans are citizens. Veterans get many privileges; be humble not an entitlement baby!

Narrowing #TheExpanseBoardGame – or – Expecting too much from theme

IMG_2055My first impressions of The Expanse Board Game (WizKids, 2017) were less-than-favorable. In the few weeks since I have been able to sit back and reappraise my feelings towards the game. I now see that I focused too much on theme and not enough on game play. If I remove many of my feelings about the theme, the game that emerges is a good influence-placement game using the theme of the The Expanse TV series.

I will be the first to admit I am not a hardcore fanboy of The Expanse, but I do like the TV series (Seasons 1 & 2) and have enjoyed the first few books. I came to the franchise backwards, seeing the TV series before I started reading the books. In several ways my perception of theme is colored by the TV series. The Expanse Board Game draws almost exclusively from the TV series, so in my first impressions I inevitably compared the two. In my first impressions I didn’t like the game because I kept trying to see the game as a replay (or version of) the TV series. The Expanse Board Game, though based on the TV series, is actually a very different look at the franchise. I should have paid more attention to the front matter in the rule book:

The Expanse is a game of politics, conquest, and intrigue for two to four players. Players spread their influence through the solar system onto important Bases using characters and events in the Expanse Universe, and must make clever use of their special faction abilities to gain an edge.

But even this summary is a bit misleading as I believe there is little “politics,” no real “conquest,” and very limited “intrigue” in the game. What The Expanse Board Game does deliver is a (sorta) asymmetrical influence-placement game based on The Expanse Universe.

Politics – When I see a political game I expect negotiation or a focus on indirect warfare (the Diplomatic, Intelligence, or Economic factors). The Expanse Board Game has no real negotiation element, a bare nod to diplomatic (i.e. the UN Diplomat cubes) and only a limited nod to economic (each factions key resources).

Conquest – Unless one conflates the definitions of conquest and influence there is no real conquest in The Expanse Board Game. Even when there is “confrontation” the result is limited to removal of fleets or influence cubes. Sure, fleets must be rebuilt but the relatively non-violent nature of the confrontation does not make it feel like a conquest to me.

Intrigue – Intrigue to me comes across as some form of secret plans or the like. Certainly, there is an element of secrecy in The Expanse Board Game but even that element is minimized as the game has almost no hidden information. Indeed, the game is mostly open information with cards on the Action Track visible to all and Kept Events remaining face-up in front of the players.

Asymmetrical Abilities – What The Expanse Board Game does well is using theme in the asymmetric abilities of the factions. From the UN being able to use superior planning to take the second card on the Action Track at no cost to the Martian battleships and the like, the use of theme to differentiate the factions is the most successful part of the game. This trend continues to a degree in the Faction Special Tech Cards that enter after different scoring rounds. These special abilities all are keyed to the placement – or
removal – of influence.

Influence – What The Expanse Board Game comes down to is influence. The game
is actually very simple; have the most influence at the right time for Scoring. Influence has two elements – orbital control and bases. Given the somewhat secret element of Bonus Sector selection, the players are challenged to have the right influence at the right times in the game. Players may find they need to “shift” influence around during the game as they try to guess (or manipulate) where the next Bonus Sector will be scored.

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Courtesy syfy.com

Rocinante – The Rocinante was actually the part of the theme I had the most trouble wrapping my head around. In the TV series the Rocinante and crew are the focus; the narrative element through which the story is told. In The Expanse Board Game the Rocinante has a far different role. With control of Rocinante going to the faction with the lowest Control Points, the ship becomes more of a pawn than a true protagonist. It is a bit disconcerting (disconnected from theme?) to see the ship only be used as a fleet (albeit one that can’t be removed) with special abilities that only come into play during Scoring. The special abilities also still very limited. Of the four, I actually find the Amos Burton ability the most powerful (“Remove 1 opposing fleet in the Rocinante Orbital for each friendly fleet there (including the Rocinante)”) which, to me, again doesn’t quite square with the TV Series where James Holden (special ability – “Place 1 influence anywhere”) comes across as the central character. I also have a bit of thematic dissonance when the Rocinante is controlled by the Protogen faction. So great is this dissonance that I have to rationalize the situation by telling myself that the Rocinante was not really being “controlled” by Protogen but more properly is being “manipulated” by the corporation.

Reappraising The Expanse Board Game

By reducing my expectations of theme, my respect for The Expanse Board Game has actually grown. The game is about placing influence – and little else. It uses the theme of The Expanse Universe to derive the asymmetric abilities of the factions. The Rocinante – a ship and crew with a key role in the TV series and books – has a lesser role in this game. In the end, The Expanse Board Game delivers what it promises – an Expanse-themed influence-placement game playable in around 60 minutes.

#FirstImpressions #TheExpanseBoardGame (WizKids, 2017)

From the publisher’s blurb:

The Expanse, a board game based on the Syfy television series of the same name, focuses on politics, conquest and intrigue similar to the board game Twilight Struggle, although with a shorter playing time. The card-driven game uses key images from the show, along with action points and events that allow players to move and place “Fleets” and “Influence”. (BGG)

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Authors collection

It is not often that a publisher’s blurb captures a game so completely as WizKids has done for The Expanse Board Game (TEBG). After purchasing the game and playing it a bit, I am torn in my feelings for the game. To me, TEBG feels very much like a “classic” Eurogame – in a negative connotation of the definition; great mechanics with a pasted on theme.

The BoardGameGeek Wiki defines Eurogames as follows:

“Eurogames (or alternatively, Designer Board Games or German-Style Board Games) are a classification of board games that are very popular on Board Game Geek (BGG). Though not all eurogames are European and not all of them are board games, they share a set of similar characteristics. A game need not fit ALL the criteria to be considered a Eurogame.

Most Eurogames share the following elements:

  • Player conflict is indirect and usually involves competition over resources or points. Combat is extremely rare.
  • Players are never eliminated from the game (All players are still playing when the game ends.)
  • There is very little randomness or luck. Randomness that is there is mitigated by having the player decide what to do after a random event happens rather than before. Dice are rare, but not unheard of, in a Euro.
  • The Designer of the game is listed on the game’s box cover. Though this is not particular to Euros, the Eurogame movement seems to have started this trend. This is why some gamers and designers call this genre of games Designer Games.
  • Much attention is paid to the artwork and components. Plastic and metal are rare, more often pieces are made of wood.
  • Eurogames have a definite theme, however, the theme most often has very little to do with the gameplay. The focus instead is on the mechanics; for example, a game about space may play the same as a game about ancient Rome.”

TEBG hits all of these points, but with mixed results.

TEBG does a good job of capturing the feel (theme) of The Expanse TV series. Using Eurogame mechanics the players place influence (tracked using small wooden cubes) on various bases throughout the Solar System. To place influence usually requires a fleet in the orbital above the base. Although the game mechanics are simple, each player/faction has unique asymmetric abilities which allow them to “break the rules” in thematically appropriate ways. For instance, while is usually cost 1 Control Point (CP) to take the second action card, the United Nations (UN) player has Planning as their initial Technology which means the first two action card slots cost 0 CP. As the game progresses, more thematically-appropriate technologies are gained by each faction.

“Combat” in TEBG consists of removing influence or fleets (which can be rebuilt). This is not a cooperative game; ruthlessly building your influence while reducing your opponents is the real core mechanic.

TEBG uses much artwork from The Expanse TV Series. Although this makes the game appear like The Expanse, some of the artwork does not have a clear connection to gameplay. For instance, the action card Scopuli can be used for 2 Action Points or as an Event by the Martian Congressional Republic (MCR) or UN. The Event states, “Place 1 influence on each Saturn Base where you do not have influence.” I do not see how this is related to the Scopuli in the TV series which is [SPOILER ALERT]:

…a Martian light transport freighter from Eros that was in service to the OPA. One of its crew was Julie Mao and it was attacked by the Stealth Ship Anubis. It was later used as a lure in the ambush and destruction of the Canterbury.

To me this is a thematic disconnect. I think Scopuli should be used as an Event to the advantage of the Outer Planets Alliance (OPA) or ProtoGen. Granted, most of the action cards have a picture that ties well to the event described, but I think to make the connection one must be a real fanboy. If a player is not knowledgeable of The Expanse the immersion into the game will not be served by the graphics.

The full impact of all these design and graphics decisions is an area control game that looks like The Expanse. The game comes across as very functional; simple game mechanics with some asymmetric differences in a kinda staid, plain package.

Finally, I have an issue with the component quality in TEBG. The board uses a non-glossy finish that, while good for pictures, has already shown rubs and scratches after just two plays. I also have a major problem with the Quick Start Rules which use white text on a semi-transparent background over a starscape page. The font, smaller than that used in the main rule book and the third layer of printing has lost all its edges and is nearly impossible to read.

It is going to be interesting when The Expanse Board Game lands on the Family Game Night table. All of the RockyMountainNavy Boys know a bit about The Expanse, but none are fanboys, Thus, the success of this game will stand not on theme alone (which appears to be much of the buzz around the game) but on its ability to blend graphics and gameplay into a enjoyable gaming experience.

 

#RPGThursday – Ship Files: Atticus Class Freelancer (Moon Toad Publishing, 2017)

 

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Courtesy RPGGeek

Ship Files: Atticus Class Freelancer, Written by Ian Stead, All Artwork and Layout Ian Stead, Compatible with the 2d6 SCIFI OGL and The Cepheus Engine SRD, Copyright © 2017 Moon Toad Publishing.

Atticus is my first Moon Toad Publishing (MTP) Ship Files book. I am a fan of Ian Stead (@biomassart on Twitter) and greatly enjoy his work for Gypsy Knight Games and their Alternate Traveller Universe/Cepheus Engine Setting Ships of the Clement Sector. I had seen several other MTP products but it was not until very recently that I made the connection between MTP and Ian.

Atticus is a 100 dTon fast (Jump-2 / 6G acceleration) multi-use vessel  – a perfect ship for a small group adventure in a small-ship universe setting. But what really sets the Atticus apart from the usual slew of Traveller/Cepheus Engine ships is the fact it is a tail-sitter! This makes Atticus a design closer to hard scifi than the usual “airplane in space” found in so much space opera. It also harkens back to classic Traveller RPG designs such as Broadsword or Azhanti High Lightning where the decks were stacked. In some ways I have to wonder if Atticus is Ian Stead’s version of Rochinante from the TV series The Expanse. Regardless, Atticus is an interesting design that can be dropped into any Cepheus Engine adventure from space opera to hard scifi.

The Ship Files book is a 24-page full color pdf. The file book starts with an in-universe description of the Atticus that right up front addresses the unusual configuration. This part is not to be skipped for there are many little details that a referee (or player) could use as adventure seeds. Statistics using Cepheus Engine are provided, as well as many line and color drawings and deck plans. Actually, there are two variants presented; the standard and a non-jump version. An example crew is also provided; three instead of the usual four members because, “it is currently one person down, the crewman having left over an argument about pay” (p. 16) Speak about an adventure seed!

MTP Ship Files books also include a two-page Spacecraft Record sheet. This sheet lays out the ship statistics in a much easier to understand manner than the simple table usually presented in Cepheus Engine.

I was very pleased to see that Ian took advantage of several Cepheus Engine products beyond the basic System Reference Document in creating this ship. Ian used the spectacular Anderson and Felix Guide to Naval Architecture (2E) published by Gypsy Knight Games as well as the recently released Cepheus Engine Vehicle Design System. I am very glad to see third-party publishers taking advantage of each other’s products; it builds community and gives us customers a better product!

Ship Files: Atticus is not without its flaws. Page numbering is laid out as in a book but the pdf file is sequential meaning page “2” of the pdf shows “1” at the bottom. This makes the table of contents one page off from the search function. The first Spacecraft Record sheet shows the class name as “Polixenes” which I take was a previous Ship Files product. Neither of these flaws are egregious nor in any way degrade the overall superior quality of the product. This product is also a real steal at $3.99 on DriveThruRPG.

Recommendation: MUST BUY!

 

#TheExpanse Ships in #TravellerRPG

Watching “Home” (The Expanse, Season 2, Episode 5) with the Rocinante at high-g burns got me back to thinking about the ships of The Expanse and how they could be portrayed in tabletop RPGs. I previously looked at the Epstein Drive and how it might be translated into game terms for use in Traveller RPG or Cepheus Engine or Orbital 2100.

**WARNING – Minor Spoilers Ahead**

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Courtesy SyFy

Going all the way back to the first book in the series, Leviathan Wakes, the small shuttle Knight gives us some insight into the technology of The Expanse:

It wasn’t long before Alex called down, “Okay, Boss. It’ll be about a four-hour trip flying’ teakettle. Total mass use at about thirty percent, but we’ve got a full tank. Total mission time: eleven hours.”

“Copy that. Thanks, Alex,” Holden said.

Flying teakettle was naval slang for flying on the maneuvering thrusters that used superheated steam for reaction mass. The Knight‘s fusion torch would be dangerous to use this close to the Canterbury and wasteful on such a short trip. Torches were pre-Epstein fusion drives and far less efficient. (Leviathan Wakes, Chapter 3)

From the book we know that the trip covers 50,000km. Working with classic space travel time equations, we can compute the Knight is traveling at about 1.0368 m/s or just over .1G acceleration.

Later in Chapter 5 we see the Knight running flat-out at 2G acceleration. At this speed the same 50,000 km trip should take only 53 minutes, which is a bit shorter than the approximately 70 minutes obliquily stated in the book. At this point it is unclear if the 2G speed is the upper limit of the teakettle or the fusion torch at low power.

The Knight does eventually clearly light it’s torch:

“Roger that, XO. Bleeding-g burn-and-flip laid in. Angled approach course so our torch won’t burn a hole in the Cant. Time to rock and roll?” Alex replied. (Leviathan Wakes, Chapter 5)

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Courtesy NBC Universal

Here we have to interpolate the fusion torch acceleration based on Holden and his apparent weight. When lighting the torch Holden weighs 500 kilos. Assuming he is an average 75 kg to begin with, this works out to almost 7G. Interestingly, from the novella The Drive we know that 7G is the instrument limit on Solomon Epstein’s ship that he installed his new drive on, indicating that the fusion torch may have an upper limit of 7G.

In summary, we can say the shuttle Knight has maneuvering thrusters (teakettle) that operate efficiently at .1G. The shuttle also has a fusion drive (torch) that can accelerate it at up to 7G.

The Knight‘s torch drive could deliver a lot of thrust, but at the cost of a prodigious rule-burn rate. But if they could save the Cant, it wouldn’t matter. (Leviathan Wakes, Chapter 5)

The missiles that are fired at the Canterbury are also very impressive:

As if in answer, six new objects appeared on his radar, glowing yellow icons appearing and immediately shifting to orange as the system marked their acceleration. On the Canterbury, Becca yelled out, “Fast movers! We have six new high-speed contacts on a collision course!”

“Jesus H. Christ on a pogo stick, did that ship just fire a spread of torpedoes at us?” McDowell said. “They’re trying to slap us down?”

“Yes, sir,” Becca said.

“Time to contact.”

“Just under eight minutes, sir,” she replied. (Leviathan Wakes, Chapter 5)

For these six missiles to cover 200,000km in 8 minutes means their acceleration has to be around 150G!

In Leviathan Wakes, Chapter 51, Holden tries to remember how fast the Roci can go:

He tried to remember the Roci‘s maximum theoretical acceleration. Alex had already flown it at twelve g briefly when they’d left the Donnager. The actual limit was one of those trivial numbers, a way to brag about something your ship would never really do. Fifteen g, was it? Twenty? (Leviathan Wakes, Chapter 51)

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Courtesy solotalkmedia.com

In the episode “Home” if I caught the screen correctly it looks like the Roci was accelerating just over 17g. This again is in line with the book; and way faster than the 6g of Classic Traveller or Cepheus Engine and far ahead of the technology in Orbital 2100 where the alternative Nuclear Pulse Fusion Drive tops out at 1.2g! Compared to the Traveller RPG or Cepheus Engine universe, the ships and weapons of The Expanse are way faster and likely far more deadly too.

As late to the game as I am, I look forward to reading more of The Expanse series and seeing what further ship secrets are hidden within.


PS: The math for figuring time and acceleration is actually easy, but to help there is an EXCELLENT site at http://www.transhuman.talktalk.net/iw/TravTime.htm that does the math for you!

 

 

 

#TheExpanse #TheDrive in Orbital 2100 – #TravellerRPG & #CepheusEngine Mods

In a previous post, I discussed the role-playing game Orbital 2100 – A Solar System Setting Using the Cepheus Engine Game and how it could possibly be used for playing in The Expanse setting. In The Expanse, the Epstein Drive is the engine that powers spacecraft across the Solar System. But just how does the Epstein Drive perform, and how could it be portrayed in the Orbital: 2100 setting using Cepheus Engine?

When playing Traveller or today’s Cepheus Engine games like Orbital 2100, I tend to be (using Marc Miller’s definitions from T4) a “Detailed Role Player.” I stray into the “System Engineer” role at times, like for this post. Part of my intention here is to show RPG players and referees/GMs that “this isn’t rocket science” – between the setting, game rules, and the internet (and with the help of a spreadsheet/calculator) it is actually fairly easy to do this analysis.

Fortunately, we have a “canon” story that we can draw inspiration from. The novella The Drive (published in 2012 and available for free online) takes place 150 years before the events of the first novel in the series, Leviathan Wakes. The Drive tells the story of Solomon Epstein, the inventor of the Epstein Drive. It is a very short novella coming in at a mere seven pages. Those seven pages, however, give us plenty of information that can be used to derive the performance of the Epstein Drive.

“By the way, we’re accelerating at four gravities. Five. Six. Seven.”

“He wonders how much above seven he’s going. Since the sensors are pegged, he’ll have to figure it out when the run is over.” – p. 1

In the first pages of the novella, we find a common language between the novels and the Orbital 2100 setting. Like Cepheus Engine and the Traveller RPG it derives from, spacecraft performance is expressed in g’s of acceleration. One g (1g) of acceleration is 9.8 meters/second/second. [Cepheus Engine and Traveller round this to 10 m/s/s…but we will use the actual value for the purposes of this discussion] Seven g’s of acceleration works out to 68.6 m/s. Since Sol’s “sensors are pegged,” this passage also establishes an instrumentation limit of the time.

“The yacht is built for long burns, and he started with the ejection tanks at ninety percent. The readout now shows the burn at ten minutes. The fuel supply ticks down to eighty-nine point six. That can’t be right.

Two minutes later, it drops to point five. Two and a half minutes later, point four. That puts the burn at over thirty-seven hours and the final velocity at something just under five percent of c.” – p. 1

These passages help determine a fuel consumption rate.

  • Using the 90% full tank as a beginning, and given that after 10 minutes 89.6% remains, we see that .4% was consumed in that short time for an hourly consumption rate of 2.4%.
  • “Two minutes later,” or after 12 minutes of total burn, the tanks are 89.5% full; meaning that .5% has been consumed at a rate of 2.5% per hour.
  • Finally, after 2.5 minutes more – or 14.5 minutes total – the tanks are at 89.4% full, or .6% consumed for a rough consumption rate of 2.4% per hour.

Using the 2.4% rate, 90% divided by 2.4% gives us 37.5 hours of “burn” endurance – right in line with Solomon’s “over thirty-seven hours” statement.

The later passage helps compute the acceleration performance of the Epstein Drive.

  • The speed of light – c – is 299,792,458 m/s. Five percent (5%) of c is 14,989,623 m/s.
  • The formula for acceleration is a=v/t where a equals acceleration in m/s, v is velocity in m/s, and t is time in seconds.
  • Plugging in our numbers for velocity (5% of c) and time (37.5 hours or 135,000 seconds) we get an acceleration of 111.03424 m/s.
  • Dividing this by 9.8 m/s, we get 11.33g acceleration.

Eleven g’s of acceleration is quite a lot, even for Cepheus Engine/Traveller where a top-grade maneuver drive is no more than 6g performance!

“Only the acceleration isn’t the problem either. Ships have had the power to burn at fifteen or even twenty g since the early chemical rockets. The power is always there. It’s the efficiency necessary to maintain a burn that was missing. Thrust to weight when most of your weight is propellant to give you thrust. And bodies can accelerate at over twenty g for a fraction of a second. It’s the sustain that’s killing him. It’s going for hours.” – p.3

NASA and the military conducted many experiments in the 1950’s and 1960’s that established a 20g human limit to acceleration. Sol is obviously in pain, but in terms of Cepheus Engine and Orbital: 2100, just how much damage is he taking?

There are no specific rules in Orbital 2100 for acceleration effects on characters. Looking at “Falling and Gravity “in Cepheus Engine (p. 164), we see that on a 1g world, the character will get 1d6 damage per 2m of fall. The rules further specify that for higher g worlds, multiple the 1d6 by the planet’s gravity number. The Epstein Drive accelerates at 11g, which we can compute as 11d6 damage. The question is the time period in which this damage takes place. Falling is assumed to be instantaneous, but declaring 11d6 damage per combat round (6 seconds) does not seem to fit the events of The Drive. This seems excessive because an average character in Orbital 2100 (7 Strength/7 Dexterity/ 7 Endurance) only has 21 damage points until death. The “average” damage from 11d6 is 44, meaning the character is dead twice over!

Perhaps we should assume the 11d6 damage takes place every space combat round  (1,000 seconds/16.6 minutes) instead. This better reflects the painful, but non-instantaneous death like Solomon Epstein experiences. It still seems like an excessive amount of damage, guaranteeing character death.

Looking around for a solution, and not finding one in the rules, I suggest a “house rule” that acceleration couches absorb some of the damaging g forces. In This New Ocean: A History of Project Mercury, acceleration couches in the Mercury spacecraft were designed to absorb 9g (assumed to be the maximum g at reentry). If we use couches to absorb 9 of 11g, the character will have only 2g of damage (2d6) per space combat round. This means an average human may  last as long as three space combat rounds, or about 48 minutes, before sub-coming to the strangling g forces.

“Even as he struggles to make the terminal respond, he’s also thinking what the drive means practically. With efficiency like this, ships can be under thrust all through a voyage. Acceleration thrust to the halfway point, then cut the engines, flip, and decelerate the rest of the trip. Even a relatively gentle one third g will mean not only getting wherever they are headed much faster, but there won’t be any of the problems of long-term weightlessness. He tries to figure how long the transit to Earth will take, but he can’t.” – p.5

Ah, here we can use the classic formula for interplanetary travel time where a ship constantly accelerates to a midpoint, flips over, and then decelerates at a constant rate to the destination. The formula is t=2*SQRT(d/a) where like before = time in seconds, = distance in meters, and = acceleration in m/s/s. (see Cepheus Engine, p. 104)

Unlike Solomon, we do not have 11g’s of force crushing down upon us, so we can solve for the time it would take an Epstein Drive spacecraft to travel from Mars to Earth.

To figure distance, one must first realize that both Mars and Earth orbit the sun differently and the distance between the two planets is not constant. At opposition, the two can be as close as 56 million kilometers (Mkm); however, at conjunction the two can be as far as 401 Mkm apart!. On average, Mars and Earth are 225 Mkm apart.

[Interestingly, in Cepheus Engine, Chapter 6: Off World Travel, Interplanetary Travel, Table: Common Travel Times by Acceleration, there is a listing for “Far Neighbor” with a distance of 255 million km. This is close enough to the Earth-Mars average distance that I think it was the source for the entry. Orbital 2100, Chapter 6: Operating Spacecraft, Travel Times, Travel Between Inner Planets, uses a different process to determine distance (p. 71). In Orbital 2100 you start with the Basic Distance of 80 Mkm (Inner Planets: Basic Distance Table) PLUS seven squares of travel on the Travel Between Inner Planets chart (using the recommended starting setup). This works out to a total travel distance of 290 Mkm – within reason but a bit above the average.]

For the purposes of this example, lets use the 225 Mkm average. Using that average distance (225 Mkm), and Sol’s stated  1/3g (3.27 m/s acceleration), the formula gives us a travel time of Mars to Earth of just over 3 weeks. This may be a normal pre-Epstein Drive trip, given the 3.27g falls within the previously noted 7g instrument limit.

“The United Nations ordered that all shipyards on Mars shut down until an inspection team could be sent out there. Seven months to get the team together, and almost six months in transit because of the relative distances of the two planets in their orbits around the sun.” – p. 6

From this passage we can assume that Sol is telling us that the average transit time between Earth and Mars is about six months. The is an important figure to remember for later.

“And the war! If distance is measured in time, Mars just got very, very close to Earth while Earth is still very distant from Mars. That kind of asymmetry changes everything.” – p. 7

Once again, lets assume the Earth to Mars distance d to be 225 Mkm. Using the Epstein Drive with an acceleration of 11g ( a=111.03424 m/s) and solving for time t gets 12.5 hours. This is a major difference from the six months Sol was thinking about earlier. It is orders of magnitude better performance!

Think for a moment about Jupiter like Sol does. Assuming the Earth-to-Jupiter average distance is 588 Mkm, using the Epstein Drive the trip would take 1 day and 16 hours!

In Orbital 2100, the best TL 9 Nuclear Thermal Rocket (NTR, p. 41) can only travel a maximum of 330 Mkm per month, meaning it takes 1 month and 23 days to make the Earth to Jupiter transit. Even the best alternative TL 10 Fusion Drive, or Nuclear Pulse Fusion (NPF, p. 61), has an acceleration performance of 12 m/s for a travel time of 5 days and 21 hours. Even the best performing Maneuver Drive in Cepheus Engine (6g or 60 m/s acceleration – p. 122), takes 2 days and 7 hours to make the same trip.

Unfortunately, as much as we can learn from The Drive about Epstein Drive performance, the novella lacks other details like the size of the drive or the volume of fuel required. This means we will have to look elsewhere for that information, like maybe Leviathan Wakes.

In summary, the Epstein Drive is very efficient compared to the NPR and NTR in the Orbital 2100 setting. Even compared to maneuver drives available in Cepheus Engine the Epstein Drive is superior. The major drawback, as Sol discovered, is the crushing gravity of acceleration. In the default Traveller setting, the Original Traveller Universe, this is overcome by using handwavium acceleration compensators. In The Expanse, 150 years after Sol’s invention, you have “the juice.”

The juice was a cocktail of drugs the pilot’s chair would inject into him to keep him conscious, alert, and hopefully stroke-free when his body weighed five hundred kilos. Holden had used the juice on multiple occasions in the navy, and coming down afterward was unpleasant. –Leviathan Wakes


Leviathan Wakes, Copyright (c) 2011 by Daniel Abraham and Ty Franck.

The Drive (A Novella for The Expanse), Copyright (c) 2012 by Daniel Abraham and Ty Franck.

Cepheus Engine: A Classic Era Science Fiction 2D6-Based Open Game System. Copyright (c) 2016 Samardan Press.

Orbital 2100 Second Edition, Copyright (c) 2016 Zozer Games.

“The Traveller game in all forms is owned by Far Future Enterprises. Copyright 1977-2016 Far Future Enterprises.”