What drives your starship?

[atomicfloozy]

I'm working on a story about a Xeog destroyer & have been researching starship propulsion and my head really hurts from the math & physics.  Anyway, how do your spaceships move about the Galaxy?  Fusion Drives, anti-matter, warp drives, jump drives, Ion drives?  And how do you handle shuttles, drop ships & small ships that also maneuver in atmospheres & have to contend with a planet's gravity well?

I know, I'm overthinking this.

The next problem I have to work on is astronavigation and how to calculate a fixed point in space.  Being earth-centric, we use earth as the origin point, but what would civilizations from several world's use as the origin point for their calculations?  The Basics would probably use Gaea Prime, but what about a civilization that no longer has a home world, such as the Xeog?

So far these questions haven't kept me up at night.  But, man oh man, am I way behind on my understanding of astrophysics.

[orangejello]

Would the galactic center work as a standard astrogation reference point?
The galactic core in relation to known black holes and pulsars for astrogation reference points?
Just spit-balling really.

[atomicfloozy]

What I've found out so far is that as far as we know, there is a Central Massive Object (CMO) at the center of a galaxy. The CMO will either be a Nuclear Star Cluster (NSC), a Supermassive Black Hole (SBH), or both. Galactic coordinate system used by our planet uses the center of our sun as the center of a spherical coordinate system. A line from the center of our sun to the center of the CMO defines the primary direction or 0 degree longitude. The plane created by this line is the fundamental plane or equator. The coordinates of each object is catalogued with particular attention paid to the location of Neutron stars or pulsars. Each pulsar has a unique radio pulse. With a database of these coordinates, a starship would only need to find three points to calculate its position in space & the position of its destination.

Each race would use its own home world to build its own coordinate system for navigating the the Galaxy. Since the radio signals from pulsars act as a signature for each pulsar, a translation program would be able to translate the coordinates of one race's star charts into the coordinates of another race. (Kind of like the Universal Voice Box.)

So Orangejello nailed it on the astro-navigation.

I'm still working on propulsion systems for my Xeog destroyer and its 2 assault boats. I'm leaning toward hybrid fusion drives for the assault boats & a fusion drive for the destroyer to use in a star system with a warp drive to travel between systems. I'm thinking Ion drives might be great for some freighters, but not practical for military use. And I still need to read up on scram jets and jump drives.

[easyeight]

From 5150 Fringe Space:

The Known Space of the 5150 universe is more a function of the technology of interstellar travel than actual stellar cartography, organized into the nine “Rings” of civilization. Most interstellar travel is conducted via Jump Lines, and Jump Gates known as “Automatic Transfer Points.” These Automatic Transfer Points (ATP) allow movement between star systems by exploiting a network of Cosmic Strings (aka “Jump Lines”) -- fault lines in the universe --that twist and wind their way across the galaxy from star system to star system.

So in 5150 interstellar travel is done via known networks of Cosmic Strings. Here's something I wrote for Fringe Space that didn't see print, comments welcome:

A BRIEF HISTORY OF JUMP LINES

Many species have discovered the ability to access Jump Lines while pursuing some form of Faster Than Light travel that involved warped-space or “warp bubble” theory. For example, Professor Kaalani of the Gaea Prime homeworld was working on practical applications of “fold space” theory when the test vehicle simply vanished after the experimental drive was activated only to be discovered 2 months later when its transponder signal was picked up outside the home solar system. She was baffled by the incident and after painstaking review found that the craft had not exploded, nor achieved FTL…it had “jumped” down a Cosmic String before the drive failed and the craft exited into normal space.

Further research led to the first Gaea Prime interstellar expedition. While they expected they would be able to quickly travel to nearby star systems, in reality a star that is practically a neighbor may not have an accessible Jump Line. This meant that the actual position of one star system to another was relatively meaningless – sure, you could spend decades traversing interstellar space at a fraction of the speed of light to get to a nearby star, but why bother when a Jump Line got you someplace interesting very, very quickly?

Another surprise was that the best transit points to and from a Jump Line occur fairly closely to stars and planets. The mass of an object, the extent to which it warps local space-time, helps determine how many Jump Lines there are in a star system and how far they are away from stars, planets and other bodies in a star system. This meant that once a ship entered a star system it usually wouldn’t have a long transit time to its destination.



[MAP OF LOCAL SPACE VS JUMP LINES]



ABOUT SHIPS AND ATPS

Very large ships like Heavy Capital ships (Dreadnaughts, Battleships and Carriers), and special Exploration and ATP Construction Ships can mount the types of expensive power plants and special Jump Engines required to open a wormhole that accesses a Cosmic String, giving them the flexibility to travel along any Jump Line they could access.

But there was a cheaper way to get around, which led to a boom in interstellar travel and commerce –  using an Automatic Transfer Point (ATP).

An ATP is essentially large space station with massive power plants and Jump Engines, placed at the proper point in a star system to access a Cosmic String. It can utilize its massive Jump Engines to open a Wormhole to allow another starship to travel along that Cosmic String to another known ATP in another star system located along that Cosmic String.

The network of these ATPs and Cosmic Strings is known in general as Jump Lines, and are usually referred to by their relative importance in terms mimicking ancient train network terminology – Main Lines, Branch Lines, and Spur Lines.


This means the known “Rings” of civilization are more an estimate of development and proximity to other developed worlds rather than a fixed area of space, since the “Rings” are actually bands of stars connected by the ATP Jump Gates.

Almost all interstellar travel and communications happens through the ATPs, making them the focal point for transportation, communications and combat. Given the critical importance of ATPs to all races, only very rarely is one deliberately destroyed, and those responsible can expect heavy sanctions and actions in retaliation by the interstellar “community.”

As for what method of "jump" or warp tech was used, I was thinking it to be based on the concept of the Alcubierre warp drive, which creates a bubble of warped space around the ship, and then simultaneously contracts space in front of the ship while expanding space behind it. That ends itself to Star Trek style free form movement, so fit the idea of the 5150 'verse with jump lines this tech works to let the ship "warp" via a cosmic string to another star system or location.

[atomicfloozy]

That first line reads like typical Gaea Prime human propaganda! "The Known Space of the 5150 universe is more a function of the technology of interstellar travel than actual stellar cartography, organized into the nine 'Rings' of civilization." Maps I've seen of the nine rings all have the "A" line, or fundamental plane extend from the center of the Galaxy through the sun of Gaea Prime & then out through the rest of the rings. "Civilization" is defined by Gaea Prime, an empire set on claiming all of the first three rings for itself.

"There are three evils in the galaxy - the Hishen Empire, the Gaean Empire and the bugs - it is the duty of the Sisterhood and Xeogs everywhere to resist these instruments of chaos." - Commander Tayeon Sea

(My Xeog character chafes against the notion of allowing humans to set the boundaries & rules of civilization - she like many green skinned officers secretly wishes the cold war with Gaea Prime would heat up.)

[kstanley81]

Listened to a book, called the science of science fiction, was pretty good, talked about the faster than light particles theory and how it might work, lots of interesting ideas and how things would work

[stryderg]

"she like many green skinned officers secretly wishes the cold war with Gaea Prime would heat up."
Don't we all! pew-pew

It's all fun and games until the actual bullets start flying.

Depending on what you want in your stories, I see 2 basic choices:
Point to point travel (wormholes, space lanes, transition points, jump lines, etc) - well defined entry/exit points to/from systems. Makes exploration more dangerous (using non-standardized tech to explore new systems to find out if there is a transition point or not. Also kind of forces space battles to be at those points; if you control the transition point, then you control the system.

Free form travel (bubbles around the ships, plot a course and engage the hyper drive, etc) - any ship with enough power and big enough engines can plot a course and show up anywhere at any time. Transit times can be reduced via FTL super drives or slipping into hyperspace where distance has no meaning. Leaves space battles open to where ever you want them, including sneak attacks. Also may have a much higher risk of losing ships in transit or finding new and strange areas due to hyperspace storms, sling shots around black holes, etc.

[easyeight]

Unsurprisingly, I'm a rules writer so I have drafted "free form FTL rules based around Alcubierre type warp drive tech. It makes for a very different type of game. It was initially written for the Terran Trade Authority universe as a 5150-related product with miniatures, but after negotiating with the license holder they got greedy and decided to do their own rules and box game...that was 3 years ago and needless to say, their effort went nowhere and there's no interest right now in picking this back up. But the core mechanics are sound and I'll probably use them again at some point in a new setting.

This version has the "light" FTL rules, just intended as a fast way to get from encounter to encounter - but also includes the nuke weapons and energy weapons described in the TTA 'verse. I have more detailed movement rules in rough draft, including a transit time chart between actual RL star systems.



Here ya go: sbminisguy.files.wordpress.com/2017/11/5150-fighter-command-terran-trade-authority-rules.pdf

[bigwalleye]

As easyeight points out, the conventional map of the 5150 universe is not based on observable Hubble space. Rather, it is based on hyperspace travel time and direction. The nearest stars are those with the shortest travel time. The ring structure is imposed by hyperspace travel limitations, while the sectors are an artificial construct that provides a rough index of travel time within a ring. Within each ring, stellar densiities are, on average, the same – as measured by travel time. (A better, but aesthetically unpleasant model would be a series of nine stacked cylinders, connected by the Sector One “Conveyor”.)

This topology has important implications, both economically and miiitarily. Economically, the most advantageous locations are in Sector One of Ring Five. This location provides the lowest average travel time (and travel cost!) to any randomly chosen system. This confers significant trading advantages on a polity based there.

Militarily, there is certainly a defensive advantage to a position in the outer or inner ring. But this is offset by the limited expansion opportunities. A strong military presence in Sector One of an adjacent ring effectively confines military expansion to a single ring. A polity with control of the three outer rings could be stymied by a strong military position in Ring Four, Sector One. At this point, the longterm future of the Ring One polity becomes bleak. They have access to the resources of three rings, while their rival has access to six rings. Economic, and military, domination by the inner-ring polity becomes inevitable.

In practical terms, while a Ring-One polity may affect an attitude of dominance and inevitability, the truth is that topology is against them. Longterm survival is virtually guaranteed, but hegemony is likely to be transient.

[atomicfloozy]

Where is sector 1? The map I have has the sectors labeled A through H.

[bigwalleye]

Mar 16, 2020 13:16:32 GMT atomicfloozy said:

Where is sector 1? The map I have has the sectors labeled A through H.

Yes, there is a well-executed map, a pdf file named 5150 Galaxy Map, which designates 8 sectors per ring, labeled A -H clockwise. Inter-ring jump points are located in the A Sector of each ring. I don't know the provenance of this file.

5150 Fringe Space, which is the ruleset I generally base my gameplay on, specifies 6 numbered sectors per ring. The inter-ring jump points are specified to be in Sector One. No sense of direction (clockwise or counterwise) is specified, although I arbitrarily use clockwise.

There is a gazetteer in pdf format, with the filename 5150 Galaxy Map - Tables. I don't know its provenance either. It follows the 6-sector comvention, and provides details of quite a few systems. The header shows that the information is compatible with Fringe Space, Urban Renewal, Fighter Command, and Star Navy. Of these, only Fringe Space explicitly specifies a 6-sector map.

Some of the gazetteer information is inconsistent with the map. Hishia Prime, for example, is listed as being in 6,1 while the map shows it in 6,D. One of these is clearly incorrect.

With the exception of the jump-linked sectors, the two sectorizing systems are completely arbitrary. Both are equally valid. As long as the number and direction of sectors is made clear, any sector nomenclature is suitable for astrogation.

[bigwalleye]

Upon further review, I realize that the map - 5150 Galaxy Map.pdf - contains an oddity which is likely to cause a lot of confusion. The map shows regions of hegemony which extend across multiple rings in various sectors. Such a hegemony is only meaningful in Sector A, where the inter-ring jump points lie. In any other sector, two systems in different rings are absolutely isolated from one another. Travel between systems in the same sector in different rings is possible only by first traversing the jump point in Sector A. The apparent proximity of such systems is an illusion.

For example, the Zhuh-Zhuh secondary system in 1,C is actually far closer to Gaea Prime (1,A) that to the Zhuh-Zhuh secondary in 2,C. Travel time to Gaea Prime is 1/3 the time to 2,C. Since time is money, it is far cheaper to ship to Gaea Prime than to the sibling system.

[zonk]

Where is this map - pdf file named 5150 Galaxy Map
And where is this gazetteer - gazetteer in pdf format, with the filename 5150 Galaxy Map - Tables

inquiring minds wish to know

[Ed the Two Hour Wargames Guy]

[bigwalleye]

Here's the map. The table is 2.7 MB, too big to attach. I'll split it in 3, but that will have to be a separate post..

5150 Galaxy map.pdf (841.76 KB)