Posts By Cmdr.Hunter

Building a Science Fiction Universe: Beginnings

What’s this universe for, anyway?

Ok, so you want to create an SF universe – what’s it being used for?  I want to tell the story of a ship, the UES Achilles.  It might be a novel, or a tabletop RPG, or a series of novels.  Fortunately, many of the worlds built for role-playing are also good for novels – they lend themselves to the media format switch well since both are basically a print media, and telling a story over a period of several (or several dozen) hours.  The major difference is when crafting gaming supplements, which should not railroad the players into one specific path – not a consideration for a novel, where the narrative is whatever you set it to.  So basically, we need to get down to the details of what should be in this universe. (again, the purpose of this site is to illustrate the process I am taking to create my setting, take or leave what you will of this)

In my case, I want something which is reasonably hard-SF.  Something “harder” than the BSG reboot, or The Expanse.  Something that spans multiple star systems, and something where travel takes a fair amount of time, but typically not years.  A big part of that is going to be the jump drive.  Jump drives are fairly common in SF.  Battlestar Galactica and Babylon-5 both have them, and they can basically be engaged at any time – and the Galactica used it frequently to get out of sticky situations.  The parameters of the jump drive in BSG were not clearly-defined, but it was damned accurate if you had a good plotter to set the coordinates, and it couldn’t generally be used for “tactical” jumps – we only see it used in that fashion a couple times in the series, and it’s not clear whether that was due to the other ships in the fleet being civilian ships, or some other reason.  Another type of jump drive is the one found in C.J. Cherry’s “Alliance-Union” setting. (In “Downbelow Station”, the “Chanur” books, and “Cyteen”, among others) I am a big fan of Ms. Cherryh’s books, especially “Tripoint”, “Rimrunners”, and “Hellburner”.  Jump drive in the “Cherryh-verse” involves making one’s way to a “jump point” to another system (there is one for each linked system) which is not clearly defined, but once there, you go into jump space and travel in a straight line until the gravity of the destination star pulls you out into normal space.  You have to be drugged unconscious or jump space will drive you mad, and it takes a month or more to get there. There’s a lot of additional details, but basically that’s it, plus the “jump vanes” on your ship can be pulsed to speed up or slow down prior to or after jump – which gives you a lot of ∆V (Delta-V) for free and greatly reduces travel time.  The combination of sleeping in jump space and occasional relativistic travel means that characters who are in space a lot are younger than their stationside age would otherwise indicate.  In Tripoint, Tom is 23, ship-time, but he was born almost 40 years ago as stationers keep time.

One big change allowed

They say that in “good” SF, you’re allowed to change one major thing and still hold the reader’s suspension of disbelief.  (typically most SF authors agree you can also sweep 1-3 minor items under the rug) For most settings, that’s a Magic Space Drive (TM) – frequently some form of FTL – and in my case, it’s the jump drive.  My details can be found here, but that page doesn’t explore all of the nuances.  Here’s a couple of mine, with the key details repeated:

  • No explanation: I don’t want to have to explain why jump drive works.  So I don’t.  An object crashes on Earth in 2158.  Or maybe 2058, who knows.  It’s filled with 15 metallic spheres packed well enough to survive impact. (another dozen are damaged / destroyed) No one survived the impact, but the ship contained extraterrestrial bipeds.  The impact is in northern Canada, and once the major world powers get there and look around, they immediately lock it down.  The ship is taken apart and disappears into several research sites, and the world’s major powers publicly blame each other but secretly share research and eventually figure out how to make more of the devices, which acquire the name “jump governor”.
  • Instant FTL: Jump drives travel to another star almost instantaneously, taking microseconds to move light years.  They seem to require only a few kilowatts per tonne to jump, and it means that the fastest form of communication between stars is a sort of Pony Express. (Traveller would call it the XBoat network)
  • Size limits: Jump drives have several thousand parts inside, and many can’t be made smaller than a certain size.  The distance between components matters also, and so the parts can be scaled in a linear fashion until the point where they are too far apart for the jump governor to work.  This means there is both an upper and lower size limit to the governors.  A governor of a given size can move a certain range of mass, so this also means ship size is similarly constrained – from roughly 1,500 tonnes (that’s “metric tons” for you unrepentant Imperialists) to about four million tonnes.  No jump fighters in this setting, and no Star Destroyers. Also, larger ships exit and enter farther from the star or planet than smaller ones. (as gravitational force doubles when ship mass doubles – 4x the mass = twice the distance)
  • Repeat jumps take time: The drive takes several hours to cool down, forcing a limit to how fast jumps can occur.
  • Tactical FTL: Any gravity gradient of a certain strength (force, not acceleration) will haul a ship down out of jump space back into our reality – including brown dwarfs, Jupiter, Ceres, or even a small moon – although for small asteroids, it would cause a ship to exit jump space close enough to overlap with the asteroid itself, causing an impressive explosion.  This means a ship which jumped to Sol and exited jump at the jump space boundary (typically 1.5-2AU from the Sun) could spend 6 hours cooling the drive and then jump directly to Jupiter. (assuming it was outside the sun’s jump limit, and that a straight line to Jupiter didn’t cross the boundary again)
  • No WMD: It’s a simple fact that any reactionless drive or technology that allows ships to move multiple kilometers per second = a weapon of mass destruction, based on kinetic energy alone.  Rick Robinson puts it this way: “An object impacting at 3 km/sec delivers kinetic energy equal to its mass in TNT.”  Meaning a 33,000 tonne warship (one of my bigger ones) moving at 10km/s = would hit with the force of 100 kilotons of TNT – equal to 5x the power of the nuclear weapon dropped on Nagasaki, Japan.  That’s bad enough, and could still happen without a reactionless drive – the Apollo missions returned from the moon at 10-11km/s, but were a lot smaller.  My jump drive avoids that by forcing a ship leaving jumpspace to enter normal space at rest respective to the gravity peak which caused it to exit jump space.  In the case of Jupiter or Saturn, you are immediately at rest respective to that planet, but far enough out that your ship may naturally fall into an orbit around it, (due to the Sun’s gravity) depending on your entry vector.  In the case of the Sun, you fall straight towards it, but not very fast.

So, what are some of the ramifications of this?  That’s a good question.  One thing it does is allow me to get around some of the limitations of my propulsion system. (see below) Since ships can basically jump to an outer planet or very close to one of the large main belt asteroids, I can retain a setting with realistic propulsion systems and still get from Earth to Jupiter in months rather than years.

Speaking of engines… (propulsion)

Atomic Rockets has a great list of engine types and expected performance. In an ideal world, I would select something with the ∆V and thrust ratio that I wanted, and build from there, but most of the propulsion types cataloged not only don’t exist today, but their engineering details haven’t been worked out.  We know the limits from a scientific perspective, (such as chemical rockets being limited to no more than a specific impulse of about 500 seconds) but we haven’t worked out the engineering details – can the reaction chamber take the pressure at this level? How much waste heat is produced, and will that melt the nozzle? Will the cooling requirement mean huge coolant pumps?  Things like that.  Incidentally, this is one of the things which the game Children of a Dead Earth excels at – allowing you to change all the details of your engine to figure out exact performance and what will and will not work – whether your ship runs on Hydrogen and Oxygen, or Methane, Decane, or other fuels.  Basically, the two “performance” options are Chemical Propulsion, or Nuclear Thermal Propulsion (NTP).  In either case, my ships will likely have somewhere from 3kps-10kps total ∆V – probably a methane NTR, and there will be a lot of methane tankers running around the Solar System.  This assumes, of course, that I don’t build ships with Nuclear Pulse Propulsion (NPP), like the 1960s Project Orion. Orion-style NPP engines have 3x-6x as much ∆V as NTR, but they also use up the very bombs the military might want to lob at other spaceships. It’s also worth pointing out that we’ve built and tested an NTR on the ground, whereas Orion never made it past proof of concept.

Summary so far…

  • My major change: FTL travel in the form of a jump drive
  • Jump drive size limits: 1,500 tonnes – 4,000,000 tonnes
  • Instant travel, with a delay before traveling again
  • No “planet-buster” relativistic rocks (Buy the T-Shirt of this from Ken Burnside!) – the Magic Space Drive (TM) should not allow 100kps planet strikes
  • Cheap travel to the outer system
  • We don’t have to explain how the Magic Space Drive works, because… someone else built it and we’re just trained monkeys
  • “normal” travel is still with “realistic” technology – NTRs and chemical drives, and possibly Orion.

Consequences

So, what does all the above mean?  First off, I have a spreadsheet I created to do the math for the jump drive.  Ships can’t initiate a jump if the force due to gravity is above a certain limit, (I’m still defining the exact limit) and that limit means if you’re inside the boundary of that sphere, (let’s call it the jumpshell) you can’t enter jump space.  If you’re outside the shell, then when you contact it, your ship falls out of jump space at that exact point, and re-enters normal space completely stationary in regards to the object that caused you to exit jumpspace.  This means you can’t hit something at light speed. (or indeed, at all, with one exception) The Jump Shell Boundary (JSB) distance depends on the gravitational force, not gravitational acceleration.  Take 2 bricks – a 1kg brick (2.2lbs, fellow Americans) and a 4kg brick.  If you drop them off a building at the same time, and stick around to see it, (and no one calls the cops) then they will hit the ground at the same time – acceleration is constant, because accel = force / mass. (derived from F= M\cdot{}A ) There is 4x the force, however.  Gravitational force is found by F=G\cdot}\frac{M_{1}\cdot{}M_{2}}{ r^{{2}}}  meaning that the force is quadrupled if you either quadruple the mass or half the range. (and the inverse of that is true – to get 1/4 the force, quarter the mass, or double the range)

So basically, a ship 9 times as massive has to travel 3x as far from the sun before it can jump.  I want UES Achilles to mass about 18,000 tonnes, because it’s about the size of a US Navy cruiser or a large submarine. (I might change this later, but it’s my aiming point) My spreadsheet does the math according to the Gravity equation, to calculate what range gravitational force exceeds the limit for jump.  For my target ship the Achilles (which I previously called a “Cornwallis Block II Frigate”) that is 7Mkm from Jupiter, or 758LS (light-seconds) from Sol. (roughly the orbit of Mars) Recycle time after a jump is about 6 hours.  During that time, the ship would “fall” towards the central object that pulled it out of jump space.  In 6 hours, (21,600 seconds) that would be about 600km towards the Sun or Jupiter, or whatever – assuming nothing is done.  Actual gravitational acceleration is about 0.0025m/s2, (1/400g) so countering that acceleration would be trivial – it would cost around 0.055km/s of ∆V if we wanted to “hover” – that’s practically a rounding error. The jumpshell distance varies with the mass of the ship, so it could be an issue if one were to miss the Jupiter SOI and hit the solar jumpshell at the distance of Jupiter directly in front of it, since Jupiter circles the sun at 13km/s.  Also, the ∆V to get to the inner planets inside the jumpshell will not be trivial, but it would be within the fuel load of a given ship if a low-fuel trajectory is used.  This means a travel time in months to the inner planets, unless your ship is small enough that the jumpshell is inside Earth’s orbit. (your ship must be lighter than about 8,500 tonnes)

What this means is I have created a setting where the following is true: ships that are smaller than 8,500 tons can jump from lunar orbit (as long as they steer 30,000km clear of Luna itself) to anywhere farther out – Mars, Jupiter, Saturn, the belt.  They can do it for very little energy, using no fuel, and can jump again after 6 hours.  This makes travel very, very easy once out of Earth’s gravity well. (which as Heinlein said, is half the effort to get anywhere) Meaning a spaceship less than 1/6 the size of Paul Allen’s yacht can go pretty much anywhere – now we have a reason for tramp freighters.  Passenger ships would more closely resemble airliners, or perhaps Amtrak – sleeper cars which would let you travel in relative luxury, getting to your destination in no more than a few days. (6 hours per jump means 8 jumps in 2 days)  I’ll talk about it later, but this SF setting will have lots of modular ships, so it’s likely some of the transports would be a jump “carrier” which can accommodate several (or dozens) of modules and move them from one location / station / whatever to another.  imagine something the size and shape of the Destiny lab on the ISS which you live in (maybe with 1-3 other people) and that you own.  The module would be your house, similar to in this award-winning design (by a Toronto high-schooler, no less) for a space station – Asten.  Asten would have thousands of these living modules (see pages 19-20) based on NASA’s inflatable Transhab concept.  Now imagine that the modules could be inflatable like those, or rigid like Destiny, and that you could disconnect from the orbital station and be attached to a chemical rocket, then thrust to another orbit where a tug would again detach your house and link it to a jump carrier.  Zip!  Now your house is in Mars orbit, or Saturn, or Tau Ceti e, or Wolf 359.  That’s the kind of future I want to write about.  Not everything would be modular, but the modules would be what allows a huge and mobile society.  It’d be as if the shipping container house fad that’s currently in vogue were extended so that you were loaded on a truck, then a ship, then you’re living in West Africa, or Hawaii, or Singapore.

This type of jump drive also means space “patrol” ships are practical.  Not the traditional “space fighter” (which I didn’t want anyway) but something analogous to a Coast Guard cutter or a corvette – a small, limited-duration ship – because they can get closer to the inner planets now, instead of 6 weeks (or 6 months) from now. They also would be able to stay close to a base and not devote a lot of volume/mass to things like crew amenities. It also means piracy is practical under certain circumstances. If you want to move large amounts of material in bulk, then there needs to be a large cargo port further out – Saturn would be a good location in the Solar System for one where you could jump Supertanker-sized cargo ships.  In general, however, the economics at first glance would seem to favor somewhat smaller ships.

Next up – Modular Space, it’s not just for the 1970s anymore…

Next post I’ll go into the whole “modular” thing, and what I think that means.

Building a Science Fiction Universe: Sources

(pic source: Marvel’s “Guardians of the Galaxy”, copyright 2014 Walt Disney Studios)

Whether or not you intend a SF universe to be “hard”, that is, reflecting actual science and eliminating things we know won’t work given our current understanding of the real world; or “space opera”, in which anything goes (for the most part), your reader/player/viewer/consumer will expect you to establish some ground rules and to be consistent.  In Star Wars, we know there are certain ground rules regarding The Force, and we know that hyperspace requires calculations, can’t be entered while sitting on the ground, and takes time to travel through.  Star Wars takes it pretty loose, though – slightly harder is Star Trek, where there are rules as to how fast a ship can travel in warp, transporters have a certain range, etc – although the rules with transporters got looser and looser with each new series or movies.  In the latest films in the Abrams canon, transporters seem to be limited solely by plot requirements, which is a quick way to lose the respect of your SF audience. “Harder” settings like Battlestar Galactica or The Expanse have a lot more rules, and have weapons, defenses, and sensors approaching what exists in today’s world.

My “UES Achilles” setting is intended to be “harder” still, and that means lots of research.

I started creating this setting under the name “Spacelanes” in 1995.  I have several hundred megabytes of data dating back to the beginning with lists of ships, details of star systems, the jump network, history, deckplans, maps and 3D renders – all kinds of stuff.  During the past 22 years, I’ve changed what I wanted to create several times.  I was going to write an RPG, then a novel, then a wargame, then a series of novels.  It’s been my “goofing off” project since Navy boot camp in 1987 when it was a more space operatic setting with a reactionless drive.  I’m finally taking steps to create the setting proper, and write one or more novels, probably self-published.  For the purpose of providing an example for would-be authors, I want to walk through the process, and much of my prior history with this creation, so that other content creators can draw ideas for their own works.  Partly because I want to, and partly because I believe there are very few SF spaceship creations which have a “realistic” feel, or which explore the consequences and ramifications of their technology, sociology, thermodynamics, economics, and energy.  We’re going to break a few rules along the way, but the plan is to know when and why we’re doing so, to call it out, and to keep it to a minimum.  There’s a few references I’m going to make heavy use of, because they are top-notch:

Atomic Rockets – Winchell Chung’s original claim to fame was a drawing of a tank – The Ogre, a futuristic tank created by Steve Jackson Games.  Later, he penned other notable gaming illustrations, and in the late 90s, he started the first serious reference for Starmapping – 3D Starmaps.  Not long after that, he began working on Atomic Rockets as a repository of knowledge on creating spaceships.  It was something I always wanted to do and never got around to – and I’ll always be a bit jealous of that.  Atomic Rockets is unmatched as a resource on its niche topic – Winchell Chung has possibly one of the greatest private collections of spacecraft articles, designs, and artwork informing his site.  We’re going to make extensive reference to his site, because he’s laid a lot of groundwork.  I’ll note that I am not an unbiased observer – I contributed a fair amount of discussion on sfconsim-l (see below) during the early days of Atomic Rockets which eventually made it into the site in one form or another.  I’m still referenced by name in the section on crew.

Traveller – Mark Miller’s Traveller is a game known among almost any “old school” tabletop gamer for its “harder” take on SF. (and among many literary/grammarian folk for its misspelled title) The old “black book” 8-1/2″ x 5-1/2″ original version holds a special place in gamers’ hearts, and in addition to spawning 5+ versions of the game, has also influenced novels, movies, and TV shows.  A Firefly line uttered by the character “Wash” (“Hang on, travelers”) may well be a reference, and the Firefly universe closely resembles many aspects of the Traveller game, including the vast difference in tech levels on the Core worlds versus the frontier.  The Expanse universe could easily be used as a Traveller game setting, and indeed, The Expanse was a series of Role-Playing Game sessions before the creators wrote the books. (which is why the crew of the Rocinante feels so much like the traditional RPG “party”)

Ad Astra Games – Ken Burnside has been creating outstanding space settings since at least the late 90s, and prior to that worked on a number of Starfleet Battles products.  He’s the creator of the most realistic tabletop space wargame on the market – Attack Vector: Tactical.  AV:T was the first space wargame to make 3D Newtonian space combat PLAYABLE.  I’ll note I am particularly biased on this front since I helped develop the setting, did massive amounts of proofreading and some minor editing of the rules and settings books in versions 1, 1.5, and 2, and playtested many of the scenarios. (and wrote a few for follow-on products)  That said, I know of no other game where I can fire and track (realistically) multiple salvos of coilgun rounds and missiles at 2 enemy ships while manuevering in 3D space and do it without a computer and without it taking 6 days to finish the game.  Ken has also written three outstanding pieces dealing with orbital mechanicsthermodynamics, and weapons in space which should be mandatory reading for anyone trying to create a believable setting in space.  Ken also developed a version of the AV:T system for the Honor Harrington universe, and currently markets a “generic” space wargame called Squadron Strike which allows you to fly ships from ANY universe, and answer questions like “What would happen if I took the Galactica and the Enterprise 1701D up against some Star Destroyers and the Andromeda?”

Children of a Dead Earth – I don’t know much about Zane Mankowski / Q Switched Productions, but I will say that he’s created the most awesome videogame of realistic space combat ever made.  I have quibbles with the official Setting, but ship design and realism are top-notch.  This is the flipside of Attack Vector: Tactical, and they are the top of the realism field for tabletop and computer wargaming, respectively.  It’s interesting, because Burnside started with a set of preconceptions and aimed to make them realistic, whereas Mankowski started with no preconceptions, yet both did the math, and ridiculous amounts of research, and came to roughly the same conclusions – the primary difference being that Burnside’s main propulsion is an undefined form of fusion with an implausible amount of Delta-V. (from an engineering standpoint – it’s well within the limits of physics)

sfconsim-l – The Science Fiction Conflict Simulation List was created on Onelist by Chris Weuve in 1997.  Onelist became part of eGroups in 1999, and was acquired by Yahoo in 2000.  Sfconsim-l was moved to Yahoo Groups sometime in 1999.  Chris is a professional naval wargamer, and an SF wargamer, and teaches strategy and several other subjects at conferences involving senior strategists and naval notables.  The list he created has gone on to host hundreds of fantastic discussions which ironed out the basics of realistic space combat, and dashed the dreams of many a gamer, reader, or writer who hoped that the Death Star could work, stealth was possible in space, or that reactionless drives had no serious repercussions. Participants on the list come from all over the spectrum of careers, and the discussions have had input from actual physicists, astronomers, aeronautical engineers, authors and game designers, and people from dozens of random but related fields.  If you want to know what’s “realistic” or not, this is a great place to ask. (although beware of frequently-discussed arguments on the list which have been discussed to death with entrenched sides, the aptly-named “Purple/Green Arguments

Solstation.comChView, and the works of C.J. Cherryh – Jo Grant and Ben Lin are major fans of C.J. Cherryh’s writing, (as am I) and in the late 90s they created an awesome visualization tool called ChView. (Cherryh Viewer) Jo and Ben were very active in the Cherryh fan mailing lists online at that time, and it was the first real tool for viewing the stellar environment from a “3rd person view” rather than an Earth-centric one.  Other tools have come and gone since then, most notably Astrosynthesis.  I still use ChView, however, because I use a MacBook, and ChView will run under WINE.  Astrosynthesis will not. (Astro also has a number of irritating UI quirks – sometimes the simpler tool is better for the job) C.J. Cherryh is one of the great SF authors, and her books are rich with setting and character, and other than jump drive are reasonably “hard” SF.

Rocketpunk Manifesto – Rick Robinson is a freelance writer who over the years has been a frequent participant in sfconsim-l and quoted often on Atomic Rockets.  Rick has a lot of great ideas to spur discussion, and has coined a number of terms and called into question the traditional “naval” model of SF military vessels. I’ll be quoting him from time to time, and I highly recommend checking out his blog and having a look around.

High Frontier – Phil Eklund is a minor legend in the boardgaming community, unless you have certain specific interests, in which case he is a major legend.  High Frontier is Phil’s masterpiece of interplanetary travel and space mining, a strategically DEEP game, and not for the feint-of-heart. Phil also did some early background work on Attack Vector: Tactical, among many other projects.  High Frontier contains a lot of references to various space technologies which can be hard to find elsewhere – although Atomic Rockets now also has most of the information and references that High Frontier makes use of. There is a 3rd Edition which was published by One Small Step Games.  Phil Eklund recently reacquired the rights to High Frontier and is working on 4th Edition incorporating additional space technology not present in the prior versions.

I’ll likely add more to this list as we go along.

Jump Drive

Jump drives are pretty common in SF – most recently they appeared in the remake of Battlestar Galactica.  BSG ships could jump every 33 minutes without problems, but I wanted something with more restrictions than that.  I envision something closer to the jump drive in the Traveller RPG, or in C.J. Cherryh’s “Alliance-Union” setting.  Other than jump drive, I wanted everything to be very “hard” SF – meaning keeping the more futuristic elements to a strict minimum. Basically, I settled on this:

Jump Requirements

  • Jump drives need to somehow “recharge” (at least 4-6 hours before the next jump)
  • Jump drives should be small
  • Jump drives shouldn’t need much power to activate (but still need to “recharge” somehow)
  • Jump drives should work for ships larger than a few hundred tons, but no larger than a million tons (may be adjusted if I decide to expand/restrict that)
  • Jump drives shouldn’t be effective for distances longer than about 7-8 light years
  • Military ships can jump farther
  • There are consequences if the jump is not perfect (or at least “good enough”)
  • Jumps are instantaneous
  • Jumps should not be possible next to a planet, too close to a star or gas giant, attached to a station, or in an atmosphere
  • I shouldn’t have to explain how they work, just the limitations
  • Jump drives should be difficult and expensive to manufacture, so that they aren’t ubiquitous

My notes below have the details, but basically, you have to be far enough away from a mass for gravity to be below a certain force in order to start a jump, and the jump goes in a straight line until you hit another sufficient gravity well that pulls you out of jump space.  I get around explaining how they work by making them alien technology – ship crashes on Earth, crew all dead, carrying multiple jump drives onboard (basically a freighter with a small crew) – and fortunately if you take the drive apart and manufacture the components exactly, you can build something that will work once it’s activated (passed through a jump).  Also fortunately, if you scale the drive up, it will work on bigger ships, up to a point.  Details are below.

These are my raw notes for how Jump Drive would work in the “Achilles” universe:

For accurate jump:

  • Need to know mass of ship and mass distribution – specifically the location of CoM in relation to the jump governor
  • Need to know position and velocity in relation to the system primary or system barycenter (multiple star systems are less accurate)
  • Need to know exact bearing to the jump target

All objects create “bumps” or indentations in the sheet of spacetime – gravity peaks (the reverse concept of gravity well). Jump is possible if the gravity gradient is sufficiently low – 21,870.1337N or less. The actual distance out from a star, gas giant, or other large body is dependent on the masses in question. The larger the ship, the greater the distance. Close in, the mass of the primary (or primaries) will dominate, but for outer planets, the driving factor will be the planet, moon, or asteroid the ship is near. Jumps are unrestricted in open space when sufficiently far from large bodies.

Jumps are effectively instantaneous, and a ship travels along a jump vector governed by the jump axis. The jump vector must intersect a gravity peak before the jump field becomes unstable – if the vector does not encounter a gravity peak, the ship reappears in “normal” spacetime when the jump field collapses. (a mis-jump) Since it’s not an orderly exit caused by intersection with a gravity gradient, the field collapse will not be uniform and the exit position and velocity may vary significantly from expected values. Typically this will be 9-15LY from the point of origin depending on the mass of the ship and several other factors, but a small percentage of the time, it can be significantly further. For an on-target jump, the maximum safe jump distance is 7.454 LY – and this is regarded as the “normal” maximum range. Military vessels have more crew and better support systems maintaining the stability of the jump governor, and their maximum range is slightly more than 7.6LY. In practice, military ships and the desperate rarely attempt jumps longer than the maximum safe distance of 7.454 LY.

Misjumps, in addition to missing the target and having a randomized exit point and exit vector, will typically damage or destroy the jump governor and any “spare” jump governors kept onboard. In the rare event that the jump governor is not damaged, a jump can be again attempted once the jump drive has cooled.

The jump axis runs through the center of the jump governor. This controls the creation of the entry field which transitions the ship into jump space. Ideally, the jump axis should pass through the center of mass – when it does not, the jump vector will precess (“wobble”) around the axis of mass, creating a less accurate path through jumpspace. The jump governor is typically mounted on 3-axis gyro wheels to allow the governor to be rotated so that the jump axis can be centered on the mass axis. This reduces jump error to the precision of the gyro wheels in pointing the jump axis, and typically is 1 arcsecond or less.

Jump itself doesn’t use a lot of energy – maybe a few kilowatts per thousand tons to initiate the jump. At the completion of the jump, there is a lot of thermal energy in the jump governor, which prevents another jump until the governor cools. Cooling generally cannot be accelerated without causing thermal shock that cracks components and destroys the governor. Cooldown is typically on the order of several hours. Large jump governors for large ships can have some external cooling, which allows cooldown times to remain fairly constant regardless of size. If a second jump is attempted before cooldown, the ship may fail to jump entirely, or might succeed and be lost on entry when the governor fractures, or might complete the jump successfully and merely destroy the jump governor.

Jump drive origin: An unknown vessel crashes on Earth. Onboard are hundreds of jump governors, along with other technologies, most of which cannot be used, but many of which lead to breakthroughs in power storage, thermal management, metallurgy, physics, and various engineering disciplines. The vessel is recovered by the Canadian government, and quickly a consortium develops between Canada, the US, Russia, China, the UK, and Norway (all of which had fragments of the ship after impact) and several large aerospace and tech companies (Boeing the most notable). The knowledge of advanced alien life spurs an alliance which eventually develops into United Earth, and the corporate alliance led by Boeing eventually develops into the defense/tech megaconglomerate of Federal Dynamics – a public/private partnership with the UE government. Within 20 years, the secrets of jump are unlocked, UE/FD discover how to make more of them, and the first exploration ships are outfitted and begin their survey work. Over the next century, routes are opened to dozens of star systems.

Size limits: There is a practical size to how small the jump governor can be – this directly determines the lower size limit of a starship. On the larger end, there are several conditions which interact to create a maximum jump governor size. A given jump governor can jump a ship up to 1/4 – 2x the governor rating. The “sweet spot” is 0.0093165 of ship mass. This means that ships with large mass fractions may be unable to jump when most of their reaction mass has been spent, unless the ship has a second (smaller) jump drive.

Jump range of effect: Jump affects the entire ship and anything contained within, attached to, or in direct contact with the ship at the time of jump. Items which are within inches of, but not touching the ship, will be left behind.

Jump drive manufacture: The savant Bartholomew Matthias initially discovered how to disassemble and catalog the components of the jump governor. He successfully created several devices, none of which worked. Jelenn McKitry performed initial remote testing of the devices in space, and discovered how to initiate them.  After several remote tests, the decision was made to build a manned vessel for additional testing.  The UES Asimov (XS-1) carried 17 crew, including Captain Alistair Flint, Pilot Jelenn McKitry, and Dr. Irene Bhattacharya, an experimental physicist. Bhattacharya had obtained one of Bartholomew Matthias’ jump governors, and used it to determine the best points for monitoring equipment. She ran extensive tests before and after the jump with the onboard equipment, and discovered variations in the results of Matthias’ governor before and after the jump. The initial manned test was a run to Jupiter from just outside the solar jump radius. Previous tests of the Matthias governors had not been as detailed, so the differences had not been detected. After the jump, the results of the Matthias governor matched the installed governor (of identical size) in every respect – the jump had somehow “activated” the Matthias jump governor. While many of the Matthias governors had been lost over the intervening years, his meticulous documentation of their creation was intact, and Federal Dynamics was able to manufacture additional units and “activate” them on subsequent tests. Experimentation showed that they could be made larger or smaller, to a point.

Jump distances: Jump distances are limited based on pointing accuracy. If aiming at a star 7.5 light years away, if you can point the ship (or the drive if the axis is misaligned) to an accuracy of 1 arcsecond, then the circular error of probability (CEP) is between 2 and 3 astronomical units (AU). Most ships jumping to a sun-sized star would fall out of jump within 1-5AU of the star. As long as the CEP is less than the jump distance limit, there is no chance for the ship to “miss”. If the CEP is larger, then there is a chance to miss – so there is a practical limit to the distance that can be jumped, which depends on being able to properly target your destination and accurately point the ship (or the drive). Additionally, since the ship’s center of mass and axis of mass can cause inaccuracies, it means that the ship can’t be doing things which change those parameters at the time of jump – things like crew moving around, engines firing and burning fuel or causing water or fuel to slosh in the tanks, moving cargo, firing ordinance, or anything else that would muck up the jump.

end of raw notes

Final Notes

This is a work in progress, and additional info and commentary will be added over time.

 

Welcome to tau ceti space!

Ok, here we go – this is my site to document the following:

  • A SF novel about a slower-than-light (STL) mission to Tau Ceti.
  • A SF series of novels about the Starship Achilles, a fictional military spaceship in a universe I’ve been working on periodically since about 2000. It has faster-than-light (FTL) capability.
  • Tau Ceti the real star system (what we actually know), and the fictional references to it.
  • The problems involved with Interstellar travel (both STL and FTL).
  • My process of developing the items above

Over time, I imagine there will quite a bit here, but in the interim, it might be a little sparse.