Gearhead Challenge!

[veltyen]

high recycleability of materials

I worried about this myself, until two thoughts occured to me.

First off, the material scooped for refining includes other material. Considering the ammount of fuel required, these trace ammounts of material add up to a large pile of useable atoms other then hydrogen available. Most of these will be quite light, but since you are looking for CHON anyway that should be fine.

CHON is Carbon, Hydrogen, Oxygen, Nitrogen. These are the elements that make up nearly all organic chemistry. Sure trace other things are needed, but in nowhere near the same quantities.

The second thought (which involves ignoring the first point entirely

) is that the ships will probably be using fusion reactors for power. I cannot think of anything canon about the disposal of fusion reactor byproducts, the most fuel sparse method is 4H -> He, but anything below Fe gives out energy from fusion, meaning that engineering can boil up nearly any elements that you need on demand. Most of these byproducts would be non-radioative. Transferric materials might be somewhat more difficult to boil up, the occasional side trip to eat an asteroid wouldn't go astray.

Suddenly the ship is no longer an anywhere near closed system, and you can throw away anything you don't want to jump with aboard.

There is the point that the ship would need to rebuild itself up to 15 times (600 year round trip) over before it returns to imperial space. Fabrication facilities well beyond the toolshops on most vessels are going to be required.

 

[Fritz_Brown]

Tekrat04, you are right! Of course, now, I have to find my copy and re-read it....

My only difficulty with this whole idea is the assumption of finding useable source materials fairly regularly.

 

[veltyen]

My only difficulty with this whole idea is the assumption of finding useable source materials fairly regularly.

Surely there are things to find in an intergalactic gulf.

If need be you can use the New Guinea method. Sure it takes a while.....

To explore New Guinea there is a non-unique problem, it occurs anywhere there is thick equatorial jungle. The plants grow back to nearly full size in 24 hours. Hacking your way through jungle takes time, for example in the denser jungle you can only make about 5km per day. The way to explore further inland is to either carry everything and only go one way (which tends to be fatal) or to hack out that 5km path every day and leave a cache at the end. This is an extraordinarily tough thing to do, and not terribly successful at the best of times, there is a reason that the great rift valley was the last human first contact.

In traveller terms this involves many (and by many I mean MANY) fuel tankers poping backward and forth to set up a chain link of fuel caches. Using this method a gap of any distance can theoretically

be traversed. The main problem is time. This is laborious, constructing a bridge of this type over 6000 parsecs of rift space is no small enterprise, as little as one near permanent fuel source will speed things up immensely.

With enough ships...... My calculator is having troubles computing 3^3000, which is about half the number of ships required to cross 6000 parsecs continuously using this method. The number is arround 10^1200 which is well past the number of atoms in the Universe (about 10^80). These missing ships would have to be replaxed by extra time, which my best estimates would push it well past the end of the universe.

 

[veltyen]

Damn. I was trying to illustrate it was possible. Back to the drawing board

.

 

[Fritz_Brown]

Yeah, I think the question was asked elsewhere (a while back) about how much fuel is required to jump enough fuel (dTons for the fuel, anyway) for another jump. That would give you your discount for the tankers. I have done refueling chains in real life (I flew KC-135s), and the reality is that you have to have a stockpile at the intermediate points, so the tankers can be refueled, so they can refuel the mission aricraft. It took 5 tankers to redeploy 8 Marine fighter aircraft from Norway - 1 to haul cargo and act as an intermediate tanker for part of the trip, 1 to pass gas to the fighters until Iceland, 1 in Iceland to refuel fighters and the cargo/tanker, and 2 in the states to bring them down the East Coast. And, yes, some of that was extra, in case a support tanker didn't make it. But, that adds up to 700,000 pounds of JP4 to move 8 fighters and 1 cargo plane with total capcaities of less than 400,000 pounds of JP4. (Takeoff capacities of the 9 a/c were lt 250,000.)

 

[Fritz_Brown]

I will have to rely on someone else to run the numbers (my LBBs are not with me), but this does bring up the idea of putting the scientists, et al, in smaller ships, and making the massive mothership nothing but a gastank.

Yes, it might take longer to refuel the large ship, but it could traverse non-linearly to gather fuel, while the other ships could move directly across. If you had two refueling ships, 1 would go off-track to refuel, while the other provided resources to the convoy, then switch.

 

[mike wightman]

Originally posted by Bhoins:
That is one thing that needs handwaving. Here is the other. The Black Prince (EA1001) needs Jump fuel yet it has an Anti-Matter Powerplant. Grandfather's ship (Secret of the Ancients) doesn't require jump fuel and the powerplant is powered by a pocket starsystem. Since the jumpdrive isn't using Fusion to power things up (or you could use anti-matter for jump drive as well as powerplant) how does a Jump drive actually use the hydrogen? Is it the equivalent of an internal combustion and it burns it?

The reason I am asking is a rather interesting concept I had for this ship. Stick a Jump drive on a Dyson Sphere. That way you are taking a whole eco system with you.

The Ancient ship in Adventure 12 does use fuel for its drives - it is mentioned in a few places. It gets this fuel from a limitless supply inside the pocket universe it is conected to.
Using MT/T20 to design this ship at TL17 you would still need hydrogen fuel for the jump drive, while antimatter could be used in the power plant.

By TL21(MT) the antimatter power plant is increadibly efficient at producing energy, but the jump drive still requires hydrogen fuel - although at a much reduced amount.
You can build jump projectors as weapons.

How about using a white globe to provide the jump bubble at TLs beyond 21? Then you could have an antimatter powered jump drive

According to the expanded TL charts in Grand Census and the MT Referee's Companion mobile worlds via jump space are possible at TL21.

Hmm, jump capable Dyson spheres...

I'm borrowing that one, if I may

 

[flykiller]

Hmm, jump capable Dyson spheres...

which would be more impressive? a jump-capable dyson sphere, or the manufacturing facility that could construct it?

 

[mike wightman]

Definitely the Culture that can build them

 

[daibaka]

Sounds to me that in addition to the huge mother ship, you're going to need high-jump capable scouts and tankers to lay out the network of fuel caches and an additional military contingent to make sure they stay where they are put!

 

[veltyen]

My current back of envelope fleet

A dozen 500,000 dTon J6M1 colony ships. Each has 20 1000dTon J0M2 resource recovery and landing vessels with enough low-berth space to accomodate 12,000 people, as well as habitat and factory facilities. Each of these has a small fleet of squadron jumping J6M1 scout vessels (about 10 per ship, but they might need more) that will be minimum possible size (300-500dTon).

The minimal weaponry carried should be enough to forestall any directly opposed military action. The scouts and colony ships all have the highest possible rating of sensors and communications available, generally they should get the drop on any foe. Minimal weaponry includes a small meson spinal on the colony ships as well as mining and beam lasers on the (armored) resource vessels.

I am assuming an escort of military vessels to the edge of the imperium, and possibly further. A couple of AHL's as escort for example may be useful.

Maximum population of sentients for the fleet is arround 400,000, though any more then 100,000 people awake at any one time would be a problem.

The plan includes the possibility of vessel loss from enemy fire or accident without seriously affecting the mission. Of the 12 leaving imperial space one or more vessels is expected to fail on the way to the target, the colony ships in the worst condition will be left as the basis for a colony, and the remaining ships will return to imperial space. There is also a possibility of leaving a colony in the rift, depending on the failure mode of damaged colony ships on the way there and back.

 

[flykiller]

There is also a possibility of leaving a colony in the rift, depending on the failure mode of damaged colony ships on the way there and back.

this is indeed a point. the expedition will have to be equipped to put down and start a colony, if necessary.

 

[Enoff]

Sounds like all the resources of the empire are being diverted on a questionable return of investment. Unless the high command is as incompetent as the Austro-Hungarian General Staff I don't see how this operation would be sanctioned.

Perhaps this is a political group of questionable loyalty and orientation fleeing to exhile? aka the Pilgrims fleeing to American from persecution in England or Huguenots from France? Doesn't mean they have to leave in a rush perhaps the Empire wants them to leave and provides some support.

 

[veltyen]

I don't know about return on investment. Even a fleet of 12 500kdTon ships isn't that much. Fully equiped for 5TCr or so.

To put this in perspective that's about the same as 2 dreadrons.

Because of the expected mission there are no ongoing costs, after the initial outlay the Imperium just sits back and watches. Some way to ensure that a ship returns would however be a nessecity.

This for several 100 years (potentially 1000 years) of research and exploration by fanatics, as well as the chance to put Humaniti even further from harms way.

Never mind what objective worth the anomaly has.

 

[Enoff]

Don't take me seriously, I was being jokingly critical. I am reading David Weber's book "In Death Ground" which is about a sudden stellar invasion of human space by an awful group of bugs.

My mind set was when I was reading the suggestion of outposting so many ships off to nowhere was that I might need them to stop a rebellion or invasion elsewhere. Budgets are tight even in Stellar Empires.

Look at us Americans, we have one of the richest economies on the planet and already we are in the hole by 500 billion just because of the last couple years of overspending.

 

[veltyen]

Budgets are tight even in Stellar Empires.

Depends on the reward for investment.

Look at us Americans, we have one of the richest economies on the planet and already we are in the hole by 500 billion just because of the last couple years of overspending.

I'm not going to reply to this directly, that would have to go to the political forum.

Indirectly though think of this as the equivalent to landing someone on the moon. It one-ups a rival (the zhodani core expedition) and while expensive most of that money just gets plowed back in to the Imperial economy. Many shipyards are going to do quite well out of this endevour.

 

[TheDS]

Wow, popular thread! Half a dozen comments added whilest I was typing out my first, which I thought was going to be like #4.

Anyway, I assumed MT/FFS1 as the basis, since that's what I'm most familiar with, and that uses 5% per jump, and that is why for all ships I was able to specify that they would EASILY be capable of TWO J6's without need to refuel.

Reading over the comments so far, I have realized that there DOES need to be extensive manufacturing support, which I managed to forget somehow. How about one machine shop? Oh, more than that, yes, you will basically need a mobile A-class Starport with you. How's about another 250,000 ton ship, then? This ship would be mostly framework and machine shops, allowing - during periods where it was going to take longer than 1 week to find the next jump coordinates - ships to rotate in as their maintenance schedules come due.

I have little doubt that ships will be required in many cases to go a long period between annual maintenance.

The ship used for carrying the passengers needs a bit of update as well. I don't know why it didn't occur to me that this century-long journey would require the bulk of the passengers to be low-berthed. We will also need plenty of spare people.

Ok, first off, the warships will have frozen watches. Normally, the military contingent will not need people to man weapons and stuff like that, so probably 3/4 of the crew can be frozen watch. Get into trouble, and you can pop out as many as you need when you need them.

Secondly, all ships will want to rotate people over the course of the trip. Normal operations will provide for the minimum possible number of people to be awake at any given time to achieve the - probably desireable - ratio of 1 person awake per 19 asleep mentioned earlier. The warships will be able to get away with a slightly lesser amount by rotating through the frozen watch.

Other tech: I assumed fusion would be the way to go, since it's the best power source that's "free". Antimatter must be MANUFACTURED, and since there is always loss, and since you'd need a seperate power source to make it, why have two engines? The point of an antimatter power plant would be to save space, right? But if you have to have an even LARGER plant devoted to MAKING it, you lose much more than you could have gained. Antimatter power plants assume an existing infrastructure where you can refuel anywhere, kind of like modern day gasoline. Hydrogen, on the other hand, can be found just about anywhere, and require little more effort than GG skimming or melting an ice body. Radioactives (for fission) require mining and refining; why waste the space?

We WILL need a mining operation, though, unless we run into aliens willing to sell us raw materials. Where to get all those parts? We must build them from raw materials. Anyone intending to use type-5 life support (full habitat with plants and animals) is STILL going to need to replace losses in the recycling cycle, things like fertilizer. Even cows just standing there still waste energy by resisting the pull of gravity and giving off body heat. You can't recoup all they eat from their droppings.

If we were smart, we'd do this right by patiently building up a string of colonies to serve as way-stations, like the Zhos did. They didn't go to the Core the first time, they spent a great deal of time and resources to build a series of island supply bases, and that is the way to go about a journey that is so very far beyond your capability - you break it down into journeys that ARE within your capability.

 

[mike wightman]

Hmm, so where is the Earth getting all of its new materials from. All those cows using up energy

You make new fertilizers from the products extracted from your waste - nothing is thrown away, everything is recycled.
In a closed system all materials can be recycled, providing you can put in the energy to do so - and the magical Traveller fusion power plants provide all the energy needed to do so
As to taking along machine shops etc. if you build your ships at TL of 16 or above then they are magically self maintaining - either that or it's all Darrian propoganda

The Zhodani began their Core expeditions at a much lower TL and hence had to adopt a "fleet and resource base" approach.
The Imperium could build TL16 explorers on many of its worlds in 1115, even hybrid TL16/17 craft can not be ruled out since:
a) a TL16 world could have some technologies as high as TL19 (CT Grand Census/MT World Bulder's Handbook)
b)there are ships like this already in operation by the Imperium as far back as the Fifth Frontier War

I'm going for a TL16/17 ship, probably about 1Mt in size, jump 6 but with enough fuel for 2 jump 4's, fusion powered (unless I can find room for 150 years worth of antimatter fuel ). Sentient computer, robot maintainance crew and frozen watch, scientists and their families fully awake throughout so that they can carry out research enroute. Colonists in cold sleep, robotic manufacturing units to build colonies as and where needed...

 

[veltyen]

I think the single ship idea has a simple flaw.

One thing goes wrong and its all over jimmy.

Misjump, unlucky asteroid hit, surprise enemy fire and all the other things that cannot be accounted for in hundreds of years of travel.

Population growth. Whether you want it or not its something that will need to be taken into account. The cost of keeping all scientists and crew on anagathics put even the most splendiferous ship to shame. That means you need replacement people, even if you limit yourself to the longer living subgroups of Humaniti.

Since you probably want to drop colonies along the way, it may be something you want to encourage. A 2% growth rate doubles the ships awake complement every 35 years or so. At a 5% growth rate you could drop off a colony the size of the ships compliment every 15 years.

On the flipside you may want a more stable population to deal with. Apart from intruding somewhat into the crews personal lives a more pressing point is what do you do with children that are ... less then perfect.

 

[mike wightman]

Here's a thought... how about a living ship

The Solomani Rimward explorations are the most recent high tech missions, the last Zhodani mission having been 350 years ago.

The Solomani sent 17 individual base ships (I'm assuming each was the base for a mini fleet) in different directions.

An Imperial Inter-galactic exploration could follow the same logic, launch several high/extreme stellar tech base ships (each one the core of a mini fleet) in the hope that one or more would be successful.

Both Vincennes and Depot, in the Deneb sector, are capable of producing such ships.

And I intend to have more than one jump drive and maneuver drive installed on each base ship