How To Cross A Rift...

[Spinward Scout]

Greetings Gentlebeings,

I've had an odd thought on my mind lately. When I look at a map of Charted Space, I keep looking at the Great Rift, specifically Reft Sector. At about 4 subsectors wide, it's maybe 30 or 40 hexes across. I keep thinking of a way to cross this and set things up to continue to cross the distance. I'm also thinking about how to do it where Jump-1 ships can cross it too. Now all I can come up with is to have a series of tankers set up across Reft Sector.

But how to go about getting them there.

I'm looking at the 5000 ton Hercules Heavy Merchant from The Traveller Adventure to do this. 510 tons fuel, and 2911 tons cargo. It also talks about how you can put up to 3 500-ton demountable fuel tanks in the cargo hold of the ship. But how many ships would it take? Surely less than 100. Or should I just Jump into the first empty hex with my Tanker and form an Empty Space Fueling Station (ESFS) and have a giant tank (I'd say 10,000 or 20,000 tons) towed nearby or built near the tanker. Ship in unrefined fuel and build a refinery next to the tank. And then when I have that established, start another in the next system?

How would you go about this?

Scout

 

[Malenfant]

Realistically speaking, those empty hexes aren't empty - they're full of rogue planets, subgiants, and brown dwarfs and probably M V stars too. So if you can detect and find those then you can use those to build refueling bases. If you're looking at a rogue jovian (but not a brown dwarf) then you've got a fuel source right there. I've written a couple of articles on these worlds in JTAS if you subscribe to that...

 

[aramis]

Well, assuming MT or TNE rules, one can make a 3J3 (60% fuel) design. For CT, T4, and T20, assume a 3J2 design, and substitute for it.

Process, on each step, 2 leave
Arrive at a point. All three have 2j3 remaining.
Ship 1 loads back to 3J3, and ship 2 to 1J3; 1 jumps on, 2 jumps back, resulting in:
Ship one has 2J3, and ship 2 has 0J3 and a refuel.

You can scale this as far as you want. Divide the distance by the J#, subtract 1, and then raise 2 to that power, and 3Jx can cross any distance IF YOU ALLOW EMPTY HEX JUMPS. Many Refs don't.

So, crossing that distance of 30 parsecs with 3J2 needs 2^14 ships... crossing it with J3 needs 2^9 ships.

In CT, you can, just barely, make a 2J4 ship. so an 8 hex is merely hard to cross. anything greater is not doable without drop tanks or massive refuel flotillas. Or finding dark objects in empty hexes and stripping them of fuel.

Under MT, you can get 3J4 or 2J6 performance on specialized couriers. 2J6 can croiss the canon rifts by the various small isolated worlds. The Islands cluster is only J8 at closest point for a through route.

That 3J4 can cross the 30 hex "True Void" with only 2^7 ships.

 

[rancke]

Originally posted by Malenfant:
Realistically speaking, those empty hexes aren't empty - they're full of rogue planets, subgiants, and brown dwarfs and probably M V stars too.

That's the real universe you're talking about. It is abundantly clear from the background that the Traveller Universe differs from the Real Universe in this respect. The empty hexes are either almost devoid of dark worlds and brown dwarfs or they are as plentiful as you say but so difficult to spot that in over a millenium no one has found it practical to find enough of them to set up a route across the Great Rift. Take your pick. Yes, both options are implausible. As I said, take your pick. But 'Plentiful and as detectable as they would be in Real Life' is not an option. It would ruin too much of the background.

The Traveller Universe may resemble the real universe on most points, but never lose sight of the fact that it is not identical to it.


Hans

PS. I don't really feel that I should have to mention this, but experience tells me that I'm wrong: What I said above is 1) an opinion and 2) only applies to the Official Traveller Universe. If you want it in YTU and somehow feel you ned my blessing, you have it.

 

[Malenfant]

This is where I grumble about how JTAS articles in print get "canonised" but JTAS Online articles don't

 

[mike wightman]

A lot of the stuff in the printed JTAS was variant rather than canon.
The online JTAS has two problems being canonized:
1. if it ain't in print, it ain't canon (some would argue that if you can't find it written on vellum in crayon by MWM's fair hand it isn't canon either

);
2. GT isn't authorised canon for the OTU, only for the alternative universe/variant the is the GTU

, and most people consider online JTAS to be GTU only

 

[aramis]

One side note: it is implied STRONGLY in The Traveller Adventure that empty hexes can be jumped to; part of the adventure revolves around finding demountables to cross a gap.

Likewise, it can also be inferred those rifts lack the density of the "dim matter" in the same manner that they lack bright matter; hence in Atlas of the Imperium, the lack of numbers in the hexes.

 

[Malenfant]

well we know that the OTU astrography isn't like the real universe anyway because the rifts don't exist in reality - there are no areas in reality anywhere near us that have a total lack of stars or other objects.

 

[lightsenshi]

(there is the minor detail of finding out these little things for those of us who only have the t20 book)

 

[daryen]

The Traveller Adventure did not imply that you could jump into an empty hex. It flatly states it. No only do the adventurers acquire demountable fuel tanks to cross a J2 gap with a double jump, but one of the adventures involves the hijacking of a Tukera calibration point in an empty hex.

There is no implication; it is canon fact.

Also, we do have at least one canon reference to the idea that empty hexes don't have to be empty: the secret Darrian base. The base is built on a rogue comet in an "empty" hex.

Finally, the nature of all of those Regency calibration points was never fully explained ...

 

[Malenfant]

It does seem that empty hexes are only empty as long as canon suits it .

I mean, we've got Deep Space refuelling stations in the empty hexes in the Scout Cruiser EA, the recalibration points in the RS, and I think there's one somewhere in the Sword Worlds subsector too...

They don't appear to be a real barrier to exploration if a group is prepared to make some effort to find things in them to build their bases on (or build ones from scratch).

 

[SlightlyLyons]

Well, in reality it would hardly mater if the rift was "empty" there would be enough stray hidrogen in deep space to ba captured and used to fuel a ship, it would just take a long time.

 

[Malenfant]

Originally posted by SlightlyLyons:
Well, in reality it would hardly mater if the rift was "empty" there would be enough stray hidrogen in deep space to ba captured and used to fuel a ship, it would just take a long time.

Too long to be remotely practical (unless you had Bussard Ramjet ships travelling at significant fractions of the speed of light)

 

[BetterThanLife]

Since mass goes up as speed increases as you approach c it is uncertain that you could ever generate enought thrust to mass ratio to attain or maintain enough velocity to make a ram scoop work. (The concept is too much like a perpetual motion machine as it is.) I am aware that regular air breathing Ram Jets have been tested and work but they still require fuel. With the Bussard RamJet you don't even need fuel once you get to velocity. (At least in theory.) I think the H-Bomb engine has more promise. (The ship rides the shockwave or energy of the blast, usually using multiple bombs ejected behind the craft for accelleration but the radiation and EMP would cause other problems.

)

Originally posted by Malenfant:
</font><blockquote>quote:</font><hr />Originally posted by SlightlyLyons:
Well, in reality it would hardly mater if the rift was "empty" there would be enough stray hidrogen in deep space to ba captured and used to fuel a ship, it would just take a long time.

Too long to be remotely practical (unless you had Bussard Ramjet ships travelling at significant fractions of the speed of light) </font>[/QUOTE]

 

[Malenfant]

Well, I wasn't saying anything about the veracity of the Bussard Ramjet concept . I think the concept was to get up to a sizable fraction of lightspeed by conventional thrusters, then turn on the "hydrogen ramscoop" which makes a very large magnetic field (much larger than the physical ram itself) that pulls in hydrogen atoms in the interstellar medium to power the drive. Or something.

Of course, since Traveller is based on 70s and earlier scifi concepts, maybe it can somehow work in the OTU

.

My favourite from those old designs was the Daedalus probe - to quote from the summary at http://sfwrg.org/d001.html

The Daedalus project was a study by the British Interplanetary Society in the early 1970s into the feasibility of an unmanned interstellar mission to Barnards Star. One of the requirements was that the probe should use current technology, or technology which was likely to be available in the near future. The propulsion system was based on that developed by the US in the 1960s for the Orion project. However, where the Orion project used nuclear fission, Daedalus was designed to use nuclear fusion. Small pellets of helium-3 and deuterium would be bombarded by electron beams from emitters mounted round the edge of the pusher plate, and would explode, the resulting plasma providing thrust. The propulsion system was dsigned to fire 250 pellets a second for four years to reach a cruising speed of 12% of the speed of light, or about 36,000 kilometers per second. The spacecraft was designed as having two stages, each powered by the same thermo-nuclear pulse engine giving a specific impulse of about a million seconds. The first stage would be dropped after two years acceleration at about 7% of the speed of light, the second stage completing the acceleration phase.

The launch mass would be approximately 54,000 tons, of which 450 tons was the scientific payload, and 50,000 tons fuel. Protection from interstellar dust was provided by a beryllium disk in front of the payload bay, and by an artificially generated dust cloud some 200 km in front of the probe as it entered the denser regions close to the target system. The Daedalus probe carried sub-probes which would be released up to seven years before fly-by, each fitted with nuclear powered ion propulsion systems.

And on top of this, it looked dead cool

http://www.daviddarling.info/encyclopedia/B/BarnardsStar.html
http://www.aemann.pwp.blueyonder.co.uk/spacecraft/daedalus/daedalus.html

IIRC there were rules in FF&S for all of these propulsion systems...

Er, we now return you to your regularly scheduled topic

 

[spank]

It really depends on where you want to cross to and from. If you just want to cross from Tobia to Cyril the furthest gap you have to cross is about 9 hexs. It also depends on what jump feul consumption rules you want to uses, CT is a flat 10% per hex for feul, TNE is jump drive size * 5 / max jump number, for a jump-6 ship this works out to 5.8% displacement per hex.

 

[BetterThanLife]

So for a CT design, and coincidentally for a T20 design you would need 90% of your displacement to be fuel. (Like that is possible.) Actually with huge droptanks, about 60% of your hull, dropped to make a jump 4-5 for the first leg then the next leg on internal fuel, I suppose it would be possible but excessively expensive. And you would be carrying about a J6 Engine just to keep the thing moving without dropping the tanks.

Interesting, back to the drawing boards. Naval Rift Courier coming up.

In MT a Jump 5 drive is about 6% of your hull and J5 fuel about 30%. So I guess you could manage it. But there is only 34% left to cram in all the other crap you are required to have in MT. That is of course if you want to make 2 jump 5s.

It would have to be a fairly large ship to take advantage of scale. (After all some things don't change size with the size of the ship.)

Originally posted by spank:
It really depends on where you want to cross to and from. If you just want to cross from Tobia to Cyril the furthest gap you have to cross is about 9 hexs. It also depends on what jump feul consumption rules you want to uses, CT is a flat 10% per hex for feul, TNE is jump drive size * 5 / max jump number, for a jump-6 ship this works out to 5.8% displacement per hex.

 

[BetterThanLife]

How to cross a rift. Or how to cross parsecs of enemy held territory. (Same problem.)

Are there any Rifts in the OTU that don't have a place that can be crossed with no more than a 12 parsec gap?

Here it is thanks to Andrew Moffett for his excellent High Guard Shipyard.

Ship: Hawkwing
Class: Hawkwing
Type: Rift Courier
Architect: Bruce Hoins
Tech Level: 15

USP
FC-A1626F2-040000-50000-0 MCr 735.210 1 KTons
Bat Bear 4 3 Crew: 24
Bat 4 3 TL: 15

Cargo: 30.000 Fuel: 660.000 EP: 60.000 Agility: 2 Shipboard Security Detail: 1
Fuel Treatment: Fuel Scoops and On Board Fuel Purification

Architects Fee: MCr 7.352 Cost in Quantity: MCr 588.168


Detailed Description

HULL
1,000.000 tons standard, 14,000.000 cubic meters, Needle/Wedge Configuration

CREW
10 Officers, 14 Ratings

ENGINEERING
Jump-6, 2G Manuever, Power plant-6, 60.000 EP, Agility 2

AVIONICS
Bridge, Model/6fib Computer

HARDPOINTS
10 Hardpoints

ARMAMENT
6 Triple Beam Laser Turrets organised into 3 Batteries (Factor-5)

DEFENCES
4 Triple Sandcaster Turrets organised into 4 Batteries (Factor-4)

CRAFT
None

FUEL
660.000 Tons Fuel (6 parsecs jump and 28 days endurance)
On Board Fuel Scoops, On Board Fuel Purification Plant, 600.000 ton drop tanks

MISCELLANEOUS
19.0 Staterooms, 30.000 Tons Cargo

USER DEFINED COMPONENTS
None

COST
MCr 742.562 Singly (incl. Architects fees of MCr 7.352), MCr 588.168 in Quantity

CONSTRUCTION TIME
120 Weeks Singly, 96 Weeks in Quantity

COMMENTS: The ship is only capable of 1G maneuver and Jump 3 with tanks retained. (Though it can make 2 jump 3s and one jump 1 without refueling in this configuration.)
If the start of the 12 hex trip, across a rift for example, is a Naval base then the tanks can be recovered, reconditioned, refueled and ready for the next trip, saving a fortune.)
If a midpoint is also a naval base the same applies.

Without tanks it is still a jump-6 2g courier.
Room for 5 passengers and 30 tons of Priority cargo. Means that the ship can be used to transfer Admirals to various parts of a command area and avoid high threat areas between start and end points. (But it would need a significant fleet presence, at either end, to ensure safety of the Courier.)

 

[BetterThanLife]

Teh best thing about that design is you don't have to put expensive to maintain refuel points in the middle of a rift. You just put a naval base at either end, and if neccessary one in the middle. You could cross the rift in Corridor sector in 4 weeks and only stop for fuel at a place where there is fuel.

If you think about it, to supply a deepspace refueling point for couriers would require a second deep space refueling point. SO your fuel can be transported on Jump 3 ships. (WHich might actually have a useful load.) Using this Jump-6x2 ship you avoid the refuel point. And if you start and stop at naval bases you even save the cost of the expensive drop tanks.

 

[daibaka]

On the subject of Bussard Ramscoop ships in Traveller, there was the Contact: Hhkarr(?) article in Challenge that described the arrival of a bunch of territorial, chain smoking lizards that turned up at their previously abandoned home worlds and set about massacreing the Vargr that had moved in during the intervening millennia. They apparently had a natural facility with gauss technology and their original colony ships were described as having bussard ramscoop drives. They had migrated at STL speeds to and from someplace outside of Julian space.

Sorry for the OT intermission...