Monday, June 27, 2011

BlueMax blog - realistic spacecraft design

Have a look here.(Update: this link no longer has the original destination.  The designs are still available in places like RPGnow, the the Zan Qing link below)

This gentleman has thought through spacecraft design very deeply.  I have picked up one of his very reasonably priced designs on RPG now (I love instant gratification).  The Zan Qing is a very plausible orbital patrol craft; I am certain I will have direct use for it, and it is great inspiration as well.  I believe it is designed for D6 Space; but reality is not bound by a rules system.

Manually organizing the database

I am learning a lot from using SQL to interpret the strings in which spectral information is provided.  I have, in fact, interpreted spectral class (thats the OBAFGKM part) on more than three-quarters the stars, and luminosity class (the sd/Ia-VII part) on more than a third.

I am now asking myself if I want to take what I have learned and go back a couple of steps to clean up some details and to code the thing as a single program.  I think I do.  There is no deadline or business case standing in the way of a high-quality result and I will have to live with this for a while.  The thing to keep track of is that I need to get to system mass data so that I can plot transit routes between the interesting stars.

Thursday, June 23, 2011

A bit more progress on the database

I have managed my first trial load of the database.  It is certainly easier to assess the distribution of things with SQL available.  The load was simplistic so took quite a while, but query response is quite solid.

Unfortunately I have miss-coded the association of desingations with stars so a bit of re-work will be called for tomorrow.  The key next step for this are:
  • Spectral parsing
  • Star detail generation
  • The visualization tool.

Wednesday, June 22, 2011

FTL Limits and otherwise

One thing I have been trying to get my head around is a sensible distance limit to FTL travel; something that can be vaguely justified in the same way as the FTL rules around flat space and potential energy can be.

One thing I will try is not limiting the distance, buy limiting the precision.  In other words, a rule something like:  "You can jump to any star you want provided that there is no star closer to your start point and within 20 degrees of arc of your destination as seen from your start"  Angle would go up or down with risk, technology, prep quality, etc..  Once I have the database ready (getting close) I will see what this means for communications maps.

I have also been thinking of having the actual jump take zero time.  I want to have as few rules as possible for "jump space" and not spending any time there makes that simpler.  One of the implications is that one could have FTL ships (or drones) jumping back and forth between stars transmitting and receiving message traffic at both ends; a process that could make communications time to a distant colony as little as 24 hours assuming FTL transit points are 2-3 light-hours apart.

I'm not sure I see this as a problem.  It would not be cheap, it would be easy to cut off, and it does provide some justification for a "strategic player" getting some information from the frontier in a timely manner.

Sunday, June 19, 2011

Another one for your reading list.

Packing for Mars, by Mary Roach is a delightfully entertaining but still serious and accurate book about human factors and space flight.  I picked it up and finished it yesterday; hilarious but I learned a lot about social interactions in confined spaces, the need for gravity to preserve bone mass, the possible application of the hormones produced by hibernating black bears, and a dozen more points that I will have applications for; and I laughed out loud more than one while I was reading it.

Rethinking the timeline

I gave a set of future-history criteria in an early post.  What I have started thinking through is a contradiction between the requirement to have cultural continuity (so that current nations are recognizable) with a major ecological crisis including large-scale population die-off and large scale migrations, all with a 500 year horizon.

So, a slightly different progress:
  • Climate change, freshwater exhaustion and population rise are severe stresses 50 years from now.  The situation is serious but (just barely) manageable.
  • About 2070, an alien species that has migrated permanently away from planetary surfaces establishes a fuel processing center around Saturn.  Part of their strategy is to increase custom by contracting to locals for food supplies (still cheaper to grow on a planet) and to trade for technology that will get those customers into space and thus buying fuel and equipment.
  • The drive for space is to establish humanity on other worlds so all our eggs are not in one basket.  Colonists would be people with a wide range of objectives from political and religious idealists to those planning to become the privileged aristocracies of new kingdoms.  The bulk of the people eager to migrate, however, would be landless and displaced peasants of the developing world and displaced industrial workers of the rich world.
  • First colonies by 2100 (if not earlier).
  • Now add a few hundred years; but not too many.

Looking more at rockets

First, I dug out my spreadsheet of acceleration and potential energy that drove the rules for jump from earlier posts, and found that the radius I had set for Sol earlier was 1.5e15 meters (10 AUs) so just outside Saturn's orbit.  Lets use that, and the average chord of a sphere of that radius is (4/3)r or 2e12m. as the transit distance.

That gives our revised time vs acceleration table, with delta-v added:


g deta-v time (days)
0.1 2.73E+06                  32.74
0.2 4.00E+06                  23.15
0.3 4.90E+06                  18.90
0.4 5.66E+06                  16.37
0.5 6.32E+06                  14.64
0.6 6.93E+06                  13.36
0.7 7.48E+06                  12.37
0.8 8.00E+06                  11.57
0.9 8.49E+06                  10.91
1.0 8.94E+06                  10.35
2.0 1.26E+07                    7.32
3.1 1.55E+07                    5.98
4.1 1.79E+07                    5.18
5.1 2.00E+07                    4.63

Rolling out the Tsiolkovsky equation  we can work out the engine exhaust velocities we need for a range of mass ratios (that is, mass at the start of the transit over mass at the end)


m0/m1   0.1 g    1.0 g 
                 2 4.0E+06 1.3E+07
                 3 2.5E+06 8.1E+06
                 4 2.0E+06 6.5E+06
                 5 1.7E+06 5.6E+06

These are high. but not inconceivable, velocities.  Basically, we have to master some pretty fancy fusion technologies to make it work.  I'll have to do a detailed wok-through to see if I am on the right track, but so far the only outright impossibility I am talking here is still FTL.

Friday, June 17, 2011

Progress report

Last night, I completed the DDL for the tables to hold the basic HYG data.  Tonight I will proceed with the code to populate them.  That should give me enough information to start playing with visualization tools.

Thursday, June 16, 2011

Time and travel

Lets say for the sake of argument that the average distance to the FTL transit limit is equivalent to the orbit of Jupiter; we'll also assume that in each system we have to cross the system (that is, travel twice the Jupiter semi-major axis) to get to the right place to transit to the next star, and that we start and end that crossing at zero velocity.  Lots of assumptions there that the final software will do in detail; and we are ignoring trade stops and refueling.  Given all of that, here's a data table:


Time .01G .1G .2G .3G .8G 1G 2G 3G
sec 8E+06 2E+06 2E+06 1E+06 9E+05 8E+05 6E+05 5E+05
min 1E+05 4E+04 3E+04 2E+04 1E+04 1E+04 9E+03 8E+03
hour       2,192     693     490     347     245     219     155     127
"days"             91       29       20       14       10          9          6          5









max V (kms / sec) 4E+02 1E+03 2E+03 2E+03 4E+03 4E+03 6E+03 7E+03

This gives transit time for various accelerations, as well as the maximum velocity reached at turnover. Our trip to Iota Persei, from this earlier post and taking the actual FTL time as zero would take eight times the numbers above.  If we have a military-grade engine and remass tankage that can sustain 3Gs we can make the colony from Earth in about 40 days.  Slowboats had better freeze the cargo: at 1% of a G it will take 2 years.  This suggests that to have the scale of empire I want, even traders will need sustained boost capability over .2G, and the more the better.

It also means that if interstellar war (or even pirates) are a real threat we will need adequate local forces to deal with a threat and provincial governors with enough discretion to use them.

Wednesday, June 15, 2011

Knowledge is power

Or at least a trade-able commodity.  The problem is what knowledge is available to whom, where and when.

Lets say Explorations Inc discovers a nice habitable world (lets call it Thrixx) with a thriving non-human population on the rimward edge of Human space.  The ExpInc ship returns to a human world, and sells this information "Knowledge is Us" a known-space-wide information consortium.

A bit later Uplift Unlimited wraps up a technology uplift contract on the coreward edge of known space.  The local UU rep contacts the local KiS office and submits a data request for possible customers.  Will the ExpInc data on Thrixx and all those excellent potential customers be there for the UU rep to buy?

This is an interesting problem.  We have a database with all sorts of information in it, plus all kinds of other events going on.  Part of the interest of a realistic star-spanning environment is dealing with the propagation of information (and dis-information while we are at it).  A solution to this will (IMHO) be a critical success factor for the game aspect of this little enterprise.  For a novel, you can keep notes on the few things that matter; for a game how to you anticipate what will be important?  I expect you have to track anything that *might* be important.

Tuesday, June 14, 2011

Seriously cool little program

At work, I use visio to toss together small design diagrams.  But that costs money - money I could use for important things like miniatures.

But it looks like I have found my home use tool -- yEd.  It is the first free program I have found that lets me toss together a good-looking crow's-foot notation ER diagram.

Sunday, June 12, 2011

Coordinates

Note to self: The systems in the Hyg database are in earth equatorial coordinates.  Ill convert to Galactic and center at Sirius (about the brightest local star) for a less human-centric world view.

Risk and space travel

Looking at some air safety stats, it seems to me that travel has to be pretty risk-free for people to consider it safe.  To have a functioning interstellar economy, especially given the length of voyages and the fact that all the time is spent in in-system travel apart from the FTL risk, and jumps are going to have to be very safe indeed - of the less than 10^-7 deadly failures per jump.  Indeed, I am inclined to think of the FTL drive is a fail-safe device.

However, there is something that has been bugging me about the FTL-drive concert  I have now.  Once you reach a range limit for the technology (you note we have not nailed that down yet) the borders become very certain and solvable.  Two technology levels might offer very different graphs of the transit routes, but in the end it is a very certain graph.  However, if we let risk enter the transition equation then the borders become uncertain.

Insured private ships will only operate at low-risk ranges (say one failure in 100,000 with one in 1000 of those "fatal").  So will military ships in normal operations.  But if I can push an extra parsec out of the fleet by taking a one-in-10,000 risk and so effect surprise would it be worth it?  Is it worth taking a series of one-in-1000 risks will get word of the alien invasion to the nearest base 3 months earlier, is it worth the risk?  If bypassing three border system and transiting right to a friendly location is all that will save your battle damaged butt, is it worth a 1-in-10 risk?

The price has to be sharply exponential, or we might end up with no frontier regions at all; but a fuzzy frontier is worth a bit of work - IMHO, YMMV.

We interrupt this future history blog

for a brief gloat about an alternate past.

yes, I played Turkey.

Saturday, June 11, 2011

When in doubt....

I expect that the 26th century will still see Marines.  They will be found wherever nations whose traditions include distinct land-operating military (British Royal Marines, Russian Naval Infantry) have ships and project force ashore from them.  That would be Earth, and any planet that has enough water to be worth building a warship there.

For operations in and from space, you will not be "sending in the marines."  For Cislunar forces the exact terminology we will use will be "Space Assault Forces." I am basing it on the prototype of the Russian Vozdushno-Desantnye Voiska mostly because this is a distinct arm of service within the Russian military.  Since the forces would originate from the contributing polities, each with its own traditions, individual formations may hold that their transitions originate with Marine, Airborne, or Army units; but new traditions  would doubtless form rapidly.

In this model, the mission of the SAF would center around:
  • Operations involving planetary assault or raiding from orbit against primarily human-habitable targets.
  • Conduct of planetary operations on habitable but unearth-like environments.  This makes adaptability and flexibility a key requirement.  SAF aircraft, for example, would have to be configurable for multiple gravities and atmospheric pressure profiles; and adaptability that would probably come at a cost compared to craft optimized for the environment.
  • SAF would probably also have formations (and elements within larger forces) that are true space combat specialists, concentrating on shipboard, zero-gravity, and domed-colony assault work.  These would probably also form teams for ship security and boarding actions.
By the way, this does not mean that I think that ships in space battles are going to pull alongside one another and swing across with cutlasses in their teeth.   Ship boarding operations happen right now.  That mission is not going to go away when it comes to spacecraft.

Neither, for that matter will search and rescue, or support for civil authorities.  The exact combination of forces that will perform such roles will depend on the polity.  Many states have certain military (like the US National Guard) or paramilitary (the French Gendarmerie nationale, the Internal Troops of the Ministry of Internal Affairs of the Russian Federation) forces that perform more civil-directed action.  Which a given polity or colony world might use would depend on population and on the traditions of the main founding polities.



The space-based polities - Jupiter and Saturn and their subject objects - would probably not have extensive ground troops, while individual combat specialists would be purely of the space-based types.  Large domes, like Luna Farside, would need internal security troops, but these would be more of the Paramilitary Police type.

Thursday, June 9, 2011

Visual presentation of astrographic data

Lets assume for a moment that we will be dealing with something like 100-200 thousand star systems.  Each important system will have data about what is there, but lets ignore that for now.

Looking at the star maps in Project Rho, it's my feeling that  much more than 30-40 stars in a single map of 3D space projected onto 2 dimensions is pushing the boundaries of human comprehension.  It is also a requirement here that we use flat 2-D images - I am not making assumptions about technology available to players or readers.  Really, some level of the presentation would have to work as a map in a printed book.

With say 150K objects, splitting them up into "subsectors" of average 30 systems each, we would be talking 5000 individual subsector maps - it it were all cubical, then 17x17x17 subcubes.  Of course, we don't want to issue players with a 5000 page atlas to try to work their way around.  We can generate any where we really need detail on the fly, but we need top-level maps.



So here is a "top level" map of Europe, courtesy of the CIA. What does it tell us?  Well, quite a lot.  It shows centres of population, oceans and land, mountains and rivers (strategically significant since they constrict and direct movement) political boundaries and relative national sizes.

All the key stuff, strategically.  We can get a rough approximation of travel times, of constricting terrain, of key objectives and obstacles.  If it were 1944, you can't plan D-day from it, but you can get a pretty good idea of the progress of the liberation of Europe.  It excludes, but could add, symbols for transportation routes, industrial and resources regions, and lots of other types of data.

So, for our star map, what sort of data could be displayed?  Well, the simplest thing is Polity capitals.  Transportation routes (with width indicating flow volume and color indicating polity) are another.



For multiple polities it might be too dense, but the boundaries of a single species could be shown by all the systems with worlds inhabited by that species.  Or if we consider a graph of a Delaunay tessellation in three dimension of all stars controlled by an empire, we could display small  dot in the middle of a line connecting a controlled start with an uncontrolled.  This also bring up a question of what might constitute "controlled" or "inside a sphere of influence.  Good thing Graph Theory is fun.

For ship routes, although most would look more like a railway timetable, strip maps are worth a glance.  Here's one from the AAA. In case you think the AAA invented them, comparable maps were used to describe routes in Europe from at least the 16th century.  The advantage of the strip map is that not only does it show the core route, but it also gives diversions from the route.  This could be useful for a planner who had developed a core approach, but wanted to look at local alternatives to avoid particular problems.  This sort of data could be presented as a 3-d map or as a classic shape and line graph - which in fact is what a road map is.

Anyway, quite a few ideas to try -- I must get back to that star data -- but I am open for more suggestions.

Software, support, and what is this all for (yet again)

OK, so I want an star/system/logistic management system to manage notes for a novel, notes for an RPG, and data for a strategic game.

There are a number of functions that are obvious, such as route and time determination software and system creation.  For a game there is certainly logistics tracking.  Also subsector map generation and the like.  Those are functions I need on my own desktop; data products like travel itineraries or images of maps can be produced and distributed as needed.

For a low-intensity function like an RPG the software is probably fine just on my desk.  For a full, formal strategic game I would have to pick one of two choices:
  • Abstract the system to the point where results can be worked out "in your head" -- which, when you get down to it, would not be a horrible bear.  It is probably safe to assume that I could also distribute player data in the form of spreadsheets - there are simple APIs for spreadsheet output.
  • Provide software for player use to allow full calculation, but only with data he can see.  The program could also generate order files that could be processed by my GM software.  The real downside to this is development time and support effort.  Do I want to take it on myself and do I want to impose it on others?
There is a third choice -- a "strategic RPG".  The players would have strategic roles within various polities and interact with one and other and the GM as they would in an RPG, but one of the outputs would be the strategic inputs to what would basically be a solo game at a low level.  I think this would be a valid option.  The players would essentially  (in addition to other RPG play) receive briefings and proposals from their subordinates and review and approve or modify operational plans at a high level.

A strategic RPG is also less sensitive to player coordination -- as a "solo game with outside inputs" instead of a conventional multi-player it can clog on without direct player supervision.  This is especially true if each side has multiple players.

I like this last one.  What do other folks think?

Wednesday, June 8, 2011

Data modeling

Two things.

One is that I did a bit of poking into the state of Object Relational Mapping.  The conclusion that I have come to (which is slightly odd for someone who has been working with OO concepts for more than 15 years) is that I want to focus on a relational design for the core star data.  SQL is a mature and widely understood technology that is superior for exploring data than the object based approaches that I am familiar with.  While maintenance and mapping apps will need object models, these might be best customized for purpose rather than aimed at generality.

The other is that, while a blog is a great place to discuss ideas in general, it is not a great tool for organizing and re-organizing design documents.  I have two choices there: I could use standard word-based design documents, or I could set up a Wiki.   Wiki interfaces are very good but are not the same bandwidth (at least for me) as a word processor.  On the other hand, they do allow easy sharing of results, much as a blog does.

Wednesday, June 1, 2011

Force shields

In an early post I speculated about "shields" as an acceptable technology; it prolongs space combat, gives the heroes more survivability, and also provides a way to justify otherwise pretty unreasonable engine exhaust velocities.

I have been re-reading the "defenses" page of Atomic Rockets and re-thinking that position.  Whatever hand-wave we might want for the engine, keeping the weapons systems effective and dramatic is probably a pretty good idea.  I have been reading sections of The Fighting at Jutland and I was impressed at how the most dramatic stories were those of the most damaged ships.

If there is a question, it is what are the most viable platforms?  Large ships with extensive defenses or small craft, but many, with big-ship-killing weapons?  I must think through my technological assumptions and come up with something that works for me.