slowboating

[TRADE MARK]

What are the mechanics of travelling by manoeuvre drive only?
I believe there was a published adventure that featured such a concept but can't recall it. I post the subject because I have encountered situations where a ship misjumps into a blank hex perhaps many hexes from a world and has no other option but to fire thrusters and accelerate at maximum G towards occupied space. All fuel gone and life-support powered down the usual procedure was to go into low berth and hope that the state of suspended animation would last the journey.
However, if all fuel is spent in the misjump how can the freezers and manoeuvre drives be supplied?
Is it simply a lost cause if a ship misjumps unfortunately into nowhere?
Also, what about slowboating as an alternative method of space travel. E.g. robot crewed ships for whom the enormous time periods mean nothing. Or even a species of star-faring life=form which ships itself in embryo stasis thaws out and grows in an artificial automated 'womb' at the appropriate time for it to develop to maturity upon arrival at the destiation system. The other ship functions being computer controlled.
I suppose this would give rise to the possibility of relatively lower tech level societies becoming star travellers.

 

[TRADE MARK]

Ive just realised that a thread already deals with a lot of this issue.Low berths. Never mind, it would be interesting though to discover a way out of the misjump dilemma. Perhaps using the power plant fuel as a separate tank reserve to power the minimal systems required to keep a crew frozen for an extended period.

 

[Icosahedron]

I have always used Power plant fuel to power the ships systems, life support, low berths, M-Drive, etc. In fact the only thing jump fuel is used for is jumping, so a misjump would have no effect on the M-drive. That's the way I read it from day one.

When dealing with interstellar distances, the acceleration/deceleration time is negligible. Just use half your M-fuel (288/2 x 10mins) for acceleration and save half for decel. Figure out your max speed and divide it into your distance to give the time taken. With everything powered down, the ship will quickly reach near-cryogenic temperatures anyway, so only a tiny power input should be necessary to keep the low berths running.
Your best defence against misjump (apart from prevention) is a jump-capable lifeboat. I have those IMTU. Oh, and always register a flight plan so someone knows you're missing.
You could also install a reserve fuel tank.

 

[mike wightman]

STL travel between the stars is mentioned a few times:

the Islands Cluster in Trillion Credit Squadron was settled by Terran colonists using STL colony ships

the Sky Raiders in the FASA adventure tilogy used STL to cross the great rift to flee from the Vilani

ships in the Imperium an Dark Nebula boardgames can cross from system to system using their sublight engines (achieving 0.9c), but it takes years...

 

[princelian]

In "reality," if you had a fusion power plant, it would require some minimum fuel consumption rate to keep the reaction going, and so an interstellar voyage of even one parsec (let's assume you have enough separate M-drive fuel to reach 0.25 c, so it's 13 YEARS in deep space) is going to burn up all fuel long before that.

If you had a system where you could power up the power plant (with near-100% efficiency), recharge the batteries, and then run the low berths off the batteries while powering down the fusion plant (again with near-100% efficiency) you could work out how long the fuel keeps the low berths running. I just don't think you could do it that way.

Instead, you'd need to build a Bussard ramjet so that you can refuel as you go. A ramjet is a huge electromagnetic field that draws interstellar hydrogen in to the fusion motor (which has to be away from the crew spaces so the relativistic protons don't irradiate your crew to death).

In one of my past TU's (IMPTU?) that was set during the dawn of J-drive, the equipment to create a ramjet was stored on warships as standard equipment because the J-drives weren't terribly reliable - misjumps (often into empty hexes) were common. The usual usage was to refuel the ship with them (a process taking months) and then jump home, but if the J-drives were damaged, then it was a longer way home.

 

[parmasson]

As a ref just say that low berths all have an RTG that can power the L.B.s for a few decades.

Take as long as you need.

 

[princelian]

RTG?

 

[mike wightman]

radioisotope thermoelectric generator (RTG) - often shortened to radio-thermal generator these days

 

[princelian]

Ah, of course, of course. Pu-238, it would generate 50%+ power for almost a century.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">1-(0.5^(1/87.7)) = 0.787% power loss per year.
= 99.213% power retained per year.

0.99213^100th power = 45.3% power.</pre>[/QUOTE]So if you were to design it with 3x required power when the Pu-238 is newly purified, it'll be rated for 100 years of life support.

Wanna bet that the low berth power cells is something that gets skipped in the maintenance done by tramp merchies?

"Oh, 70 years is *plenty* of time."
"But sir, it'll take 96.4 years to reach the next system with available fuel!"
"I see...."
<gunshot>
"Lucky for me there's two power cells I can tie together for my low berth, isn't there? And the Merchant Academy said I should work more on my Broker skill and not worry about T/Electrical..."

 

[Merxiless]

I always have ruled that a ship that misjumps, with no system in the misjump destination hex, abnd no spare fuel tankage that survived the incident is a total write-off, including the crew.

Thus, a group of characters in my campaign should not risk misjump, ever.

But if they can jump into a system with ice asteroids, or even a world with a miniscule water content in the atmosphere, or a gas giant, they can eventually jump out, if the ship wasn't too badly damaged in the misjump.

This brings to mind an idea..finding an old wreck of another crew that misjumped, except that the crew got killed, and perhaps some scant fuel survived...or something. But really...kill 'em off, I'd say.

 

[Maladominus]

Yes, I agree.

In the first place, misjumps are supposed to be RARE. Maybe about as rare as a modern commercial airplane crash. Less than 1 percent? Anyone have statistics for either?

But when a misjump does happen, the base assumption is that the crew will not make it back home. The odds are completely against them. It is not cruel for the Referee to simply assume that they are as good as wiped-out. Gone. No mas. Kaput. Hasta la bye bye.

Yes, it's possible to misjump into a heavily-populated system. This is especially true in sectors like the Solomani Rim, where most systems are literally inhabited by billions. But we should never assume that the crew would be this lucky.

 

[Icosahedron]

I assume Merxiless and Maladominus do PBEM. If I'd made a ruling that severe in my old gaming circle, I'd have needed a pistol in my belt IRL!

 

[aramis]

Based upon Imperium, somewhere around 1.5C.... (0.5Pc hexes 1 per year, IIRC.)

MT is one of the safest; jump errors are 1 in 36 aggrivated, and with typical crew with Stat 7 and 1 level in all relevant skills, taking extra time, that's 4+, so Nat2 is ONLY 2d mishap; so that's 3/36 for the 11+ fumble level required to actually misjump to the wrong place.

1*3/36*36=1/12*36=1/(360+72)=1/432 of jumps go astray.

Now, if the crew does NOT take extra time, the chances go WAY up, you need a natural 5+ to jump (7+ with DM+2), a Nat 3 forces a 2d mishap, and a nat 2 forces a 3d mishap...
So..
For The Nat 2: 1/36 * 88/216 = 88/7776 = 11/972 for misjump and 1/36 * 20/216 = 20/7776=5/1944 chance of destruction
For the Nat 3: 2/36 * 3/36=(2*3)/(36*36)=6/6^4= 1/6^3=1/216 (Or 36/7776)
combined: (36+88)/7776=124/7776

When we go hasty, well, lets just say, it's a lot worse. It becomes hazardous (always 3d) and fateful (any fail is a mishap)... and you're shooting for 11+ with DM+2; or 9+ natural... or 26/36 chance of failure, and 88/216 chance of misjump on fail with 20/216 chance of destruction on fail... So destroyed is 520/7776 , and misjump is 728/7776 overall chance on hasty jumps.

So
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Safe Jump MJC=18/7776 DC=0/7776
Normal Jump MJC=124/7776 DC=20/7776
Hasty Jump MJC=728/7776 DC=520/7776</pre>[/QUOTE]

 

[princelian]

This is exactly why the ships in my "early J-drive" campaign were equipped with Bussard ramjet systems.

In T20, the odds of a misjump are entirely dependent upon your T/Astrogation skill. It's a DC 15 check in normal circumstances, which for someone with a 14 Edu means 12 skill ranks are needed to make it automatic. (If you're Navy and took T/Astrogation as your primary military occupational speciality (PMOS feat), you can take 10 and need only 3 skill ranks.)

However, if you're rushed (+5 DC) and in uncharted territory (+10 DC) and the ship's computer's on the fritz (+5 DC), you're looking at a DC 35 check. For a 20-level character who took maximum ranks each level (23 ranks) with an 18 Edu (+4 bonus), he'd need to roll an 8 on d20. (Definately a time to hope he DID take T/Astrogation as his PMOS.)

A more realistic number would be rushed (+5), which is a DC of 20. The non-PMOS astrogator with a 14 Edu needs 17 ranks to make this automatic. The PMOS astrogator needs only 8.

The "average" T20 character after Prior History is roughly 8th level, and let's assume you hire an astrogator who took maximum ranks (11) and is fairly well educated on a high-TL world (16, +3 bonus). Such a person is 100% likely to plot a successful Jump under normal conditions (no need to roll as skill checks in d20 don't automatically fail on a natural 1), and 75% likely to do so under hasty conditions.

If the T/Astrogator has someone assisting him (+2 bonus if that DC 10 check is successful) and has "Masterwork" (i.e., expensive) astrogation programs that give a bonus to the check, he can handle a more difficult jump safely.

In previous Traveller campaigns, we had every character with the Navigation skill (which is now T/Astrogation in T20; Navigation is planes and boats) roll separately and if we didn't ALL come up with the same J-course, as well as the computer, we'd go back to the drawing board. That way, two or three people AND the computer would ALL have to fail their checks to plot a misjump.

But I always felt the high chance of misjump, from CT through MT and beyond, made the paradigm of the single-man scoutship (with the Scout with Nav-1) improbable if not impossible, so I usually house ruled misjumps out unless the circumstances were unusual in some way: less than 100D from the world, damaged systems, hasty course calculations, etc. Misjump HAS to be rare or the universe-as-presented doesn't work.

Taking Aramis' calculations for a safe jump, megacorporations lose one 400kton megafreighter out of 400 every time they jump. Let's assume they have a fleet of 4000 of them and they make jump once a month (then three weeks in port trading/unloading/loading/maintenance). That means they lose 120 per year through NO OTHER CAUSE THAN MISJUMP. I can't believe it's that high.

 

[veltyen]

Page 92: T/Astro
Page 354: Misjump section

Without the jump being rushed, then anyone can take a 10. I dunno about you, but considering my life depends on it, I'm going to let the astrogater take as long as they like. This allows an apprentice belter (level 1, 4 ranks in T/Astro, 12 Edu) happily make a standard jump plot with no chance of failure.

From Page 354 then there is a zero chance of misjumping without broken equipment (damage result), jumping in a gravity well, or using unrefinied fuel. This is a seperate roll to the astrogation plot.

 

[aramis]

That's not counting, veltyen, the ones which are off time... (mishap rolls of 7-10) and could be early or late by several days .

BTW, that was the very type of calc we used in playtest... no time limit, no damage Level 1 charater, +1 from attribute.

Taking a skill focus for +2 additional was a possibility at the time....

 

[kafka47]

Slowboating between the Stars? The most that I ever attempted was interplanetary and most players get bored of that very quickly - they are not possessing that Right Stuff. But, every so often there is an alien race or long lost expedition that causes concerns and the troubleshooters must go and find out what it is.

 

[Lochlaber]

I have several systems that are using slowboats or rather drones of some sort, traveling in normal space.

Basically, the systems involved had a colony on a 3rd world that was placed there by their last jump ship before it broke down. The home systems knew that their jump ships wouldn't last forever, planned for their eventual breakdown and to secure a constant flow of incoming resources.
Huge magnetic accelerator rings were built in space to launch the drones which were filled with and built of, processed ores, rare earth elements, etc., all of which could take bruising gravity from the initial surge and years of zero gravity and without being affected by vacumn.
Similar rings in the home system would deaccelrate the ships and send them to orbital refineries for processing. Occasionally a drone would be re-used, sending new equipment and the like back to the 'thriving' colony.

This gives me the ability to have a system that forget about the incoming drones because of a problem in say a century's courses which is then fixed, or somebody forgets to send goodies to the resource system which has died out but there is still a few years of goods enroute and of course, the arrival of a jump ship which can always beat the slow boat on delivery times.