On the bridge in-jump

[GypsyComet]

If you really want to draw attention to the Oort and Kuiper Zones in systems, you can do it a couple different ways.

A fairly benign way is to add "Space Gypsies" to the setting. Their settlements are way out in the Black, where no star becomes a Sun. Their expansion and culture mirror those of the "normal" Traveller polities, but much thinner, living in the larger rocks out beyond the Heliopause.

More neutral is the unoccupied Vast. Rocks, iceballs, dustbombs, and the occasional boilerpot, all beyond and between the realms of Man. Think "The McAndrew Chronicles"
http://www.fantasticfiction.co.uk/s/charles-sheffield/mcandrew-chronicles.htm

For a more paranoid look, consult Lovecraft, look up the Nightbrood of Spacemaster/Silent Death, or read Jeffery Kooistra's "Dykstra's War". There are things in the Oort you do not want to awaken...

Of course, these zones are so big and diffuse that you could do all three...

 

[rust]

I think we just disagree a little on the degree of "occasionally" for the first and perhaps more so on "rarely" for the second

A matter of assumptions. In my view the combination of an Imperium of
more than 11,000 inhabited planets with the number of starships required
for the interstellar trade of this Imperium, the average number of jumps
per starship and year and the average length of a jump tends to produce
a very high number, which could well balance out the extremely low pro-
bability of any jump accident involving a rogue planet. Therefore I tend
to guess that one event per Imperium and year is not unlikely.

 

[Jak Nazryth]

For relatively minor objects as has been discussed floating around in the Ort clouds of star systems, a simple solution as a GM could be to explain (and introduce a possible plot thread) that an ort-object (is that a word?) is the very thing that caused a characters ship to miss-jump. Ok, sure it was simply the player not rolling high enough, but as the GM, you could use the bad roll as any type of object interdicting the jump space with it's gravity bubble. Just have the miss-jump happen as the ship leaves the system inside jump space itself as apposed to miss-jumping instantly at the time the jump bubble is created.

 

[BFalcon]

rust: Why not?

Because the mathematicians have yet to develop a method for precise
solutions of n-body problems, and at the moment they are rather con-
vinced that such a solution is not possible.

Given the scale of the matter, if you know the mass and density of the item, you should be able, if needed, to extrapolate the position of the items you need to track with enough precision to be able to make a precise-enough position possible - remember that anything that doesn't impede on the area in question either directly or indirectly can be dropped from the calculations. Anything in the region would be shown with a sphere of influence and error, which would be larger the more out of date the information was.

Remember we're talking about a civilisation that uses Jump Drives regularly and to whom grav-tech is about the same as steam or internal combustion is to us...

I do wonder, to be honest, if any ship's navigation computer would hold more than the current subsector and (possibly) the surrounding subsectors (which may be out of date if it's a rarely-visited area).

 

[rust]

Anything in the region would be shown with a sphere of influence and error, which would be larger the more out of date the information was.

Yep, this is the second part of the problem, aquiring and processing the
data for several trillions of objects fast enough to keep the already not
very precise mathematical calculations at least somewhat up to date.

Perhaps possible for a TL 15 planet, but most of the Imperium's planets
are far below that technology level. Hardly possible for a TL 8 planet, ab-
solutely impossible for any planet with a technology level lower than TL 8
- we could definitely not do it.

And I doubt that the Scout Service has established high technology obser-
vatories and supercomputers on every planet with a low to middle techno-
logy level.

By the way, even if one had the capacity to collect and process the data
at 1 second per object, to do that for 1 trillion objects would take about
31,000 years ...

 

[DFW]

rust: Why not?

Because the mathematicians have yet to develop a method for precise
solutions of n-body problems, and at the moment they are rather con-
vinced that such a solution is not possible.

It is more a problem of an incomplete understanding of gravity. With thousands of years of observation and mastery of gravity, it isn't a problem at all.

 

[rust]

It is more a problem of an incomplete understanding of gravity. With thousands of years of observation and mastery of gravity, it isn't a problem at all.

Maybe, but as mentioned above ^^ even with a better understanding of
gravity and incredibly fast measurement and data processing methods
a simple survey of all objects of our system which are bigger than 1 km
would take millenia - far longer than the Imperium has existed and is
likely to exist.

 

[BFalcon]

Anything in the region would be shown with a sphere of influence and error, which would be larger the more out of date the information was.

Yep, this is the second part of the problem, aquiring and processing the
data for several trillions of objects fast enough to keep the already not
very precise mathematical calculations at least somewhat up to date.

Perhaps possible for a TL 15 planet, but most of the Imperium's planets
are far below that technology level. Hardly possible for a TL 8 planet, ab-
solutely impossible for any planet with a technology level lower than TL 8
- we could definitely not do it.

And I doubt that the Scout Service has established high technology obser-
vatories and supercomputers on every planet with a low to middle techno-
logy level.

Well, to be honest, it might be possible using modern computers to keep up to date, given how few objects will be close enough to influence other objects... (by modern, I mean supercomputers, not PCs - look at the cost of the computer systems in the ship designs and you'll get why I say this).

As for observatories, I'm sure that starports have an observatory built into them, but also the passive sensors on idling ships would probably be used to help improve all known stellar data in a regular basis - after all, the hubble telescope isn't much more than a reflecting telescope and a CCD - I'm sure that the passive optical sensors on a TL13 spacecraft would far exceed it in capacity and capability and would probably be a fraction of the size.

I think it all comes down to this... do you see all spacecraft getting their own data and keeping it; only the scout service doing so and then selling the data to spacecraft (as someone suggested elsewhere); or do you see the whole navigational data thing as a mutual support network (a bit like the truckers in the US) where all spacecraft log their observations at the local spaceport on arrival and then download the latest known positions as they depart?

I personally subscribe to the latter - nobody wants to end up in a misjump, so they'd sooner have free data transfer and with everyone passing their data around, any data that's contradicted by the majority would probably be thrown out as in-error, or a scout ship might go and check it for an independant verification if it's a remote system.

 

[DFW]

even with a better understanding of
gravity and incredibly fast measurement and data processing methods
a simple survey of all objects of our system which are bigger than 1 km
would take millenia - far longer than the Imperium has existed and is
likely to exist.

Only if done from Earth. If done from space with TL 12 sensors on ships flying the areas at high speed, no problem. A gravitometer can detect a 10 Dton ship out to 50,000 km. Multiply detection range for massive objects in accordance.

 

[far-trader]

As we've thoroughly hijacked the original topic into another interesting one

...I have to agree with rust that cataloging all the relevant objects would take too long, tracking them accurately would be a monumental task, and disseminating and updating said information across all the interested ships would be equally daunting. If not entirely impossible or near enough to.

However, it may be that the "deserving" systems (high tech and/or high starport = high traffic) and ships (Navy certainly, Scouts obviously, big Merchants yes, free-traders? maybe not so much... ) will have such complete data. Making jumps safer for the Navy and Scouts (shades of CT B2 misjump DMs) and safer through the better travelled systems (a new set of DMs woo-hoo ).

And perhaps we don't need to catalog every object. Just set up monitors to scan and track those objects that cross through the paths of the jump plots between the mainworlds. That should reduce the problem to solvable. Let those who would dare to wander off the routes assume the risk (small, but there, and I like Jak Nazryth's idea of blaming misjumps on that )

...hmmm, I had another related thought bouncing around here but it's left the building (only momentarily I hope).

 

[rust]

Only if done from Earth. If done from space with TL 12 sensors on ships flying the areas at high speed, no problem. A gravitometer can detect a 10 Dton ship out to 50,000 km. Multiply detection range for massive objects in accordance.

Even if it were possible to determine the mass, position, vector and speed
of an object within 1/1000 second (which I tend to consider as impossible)
and with a resulting data collection and processing rate of 1,000 objects
per second it would still take more than 50 years - and the data would be
outdated before the survey would be complete.

 

[rust]

Just set up monitors to scan and track those objects that cross through the paths of the jump plots between the mainworlds.

This makes it easier, but not much. Since these worlds are orbiting their
stars, the jump routes between them will wander through the entire eclip-
tic of their systems over time, and the Oort Clouds of the systems are al-
so moving. It should therefore of course be possible to reduce the risk
considerably, but I cannot imagine a system which could eliminate it.

 

[BFalcon]

As we've thoroughly hijacked the original topic into another interesting one

And not my doing for once... :wink:

...I have to agree with rust that cataloging all the relevant objects would take too long, tracking them accurately would be a monumental task, and disseminating and updating said information across all the interested ships would be equally daunting. If not entirely impossible or near enough to.

I still disagree - you've got possibly 1,00s of TL12 or higher passive sensors passing through each system in a year - are you honestly telling me that they can't do a little free-time free work? As for distributing the data, each ship is docked for days - with TL12 or higher data transfer rates, even a trillion records won't be a problem. Right now, I'd cringe at having to copy a 1,000 Tb (PetaByte if memory serves) database, but then I used to cringe at downloading a 9Mb file off the internet (9 hours using a 2400 modem before giving up). These days, 9Mb takes just a few minutes. I imagine that a starport would be able to offer the latest database as part of the docking fees, starting with the latest information in the local area and working out from there. How is that hard to distribute?

However, it may be that the "deserving" systems (high tech and/or high starport = high traffic) and ships (Navy certainly, Scouts obviously, big Merchants yes, free-traders? maybe not so much... ) will have such complete data. Making jumps safer for the Navy and Scouts (shades of CT B2 misjump DMs) and safer through the better travelled systems (a new set of DMs woo-hoo ).

All systems are "deserving" - at least as far as the Navy is concerned - it might be their ships that need the data someday... so yeah, I could see the scouts being sent to monitor the situation even at the more remote systems...

Yipee... more DM's to keep track of... :x

And perhaps we don't need to catalog every object. Just set up monitors to scan and track those objects that cross through the paths of the jump plots between the mainworlds. That should reduce the problem to solvable. Let those who would dare to wander off the routes assume the risk (small, but there, and I like Jak Nazryth's idea of blaming misjumps on that )

I'd just do all of them over the size of a small-to-medium ship (after all, even a larger object's path might be deflected by a smaller object). As for the tracking, those starports must have room for decent computers - surely they could track every mapped item and update when a ship comes in with updated data...? It'd reduce the amount of work the navigation computers would need to do on each ship...?

...hmmm, I had another related thought bouncing around here but it's left the building (only momentarily I hope).

Thought I heard the sound of a window breaking a while back...

 

[BFalcon]

Only if done from Earth. If done from space with TL 12 sensors on ships flying the areas at high speed, no problem. A gravitometer can detect a 10 Dton ship out to 50,000 km. Multiply detection range for massive objects in accordance.

Even if it were possible to determine the mass, position, vector and speed
of an object within 1/1000 second (which I tend to consider as impossible)
and with a resulting data collection and processing rate of 1,000 objects
per second it would still take more than 50 years - and the data would be
outdated before the survey would be complete.

Mass, not sure... position - you know the position of the stars "around" the object, so can take bearings - you know the system you're working from. You can tell the speeds relative to the observer from the red or blue shift of the object and you know WHEN it was from the range, since light travels at a known speed. If you wanted to know more, you could always send a robotic drone-ship out with enough fuel to return and take some readings for you? You could probably be able to get multiple bearings and readings from different systems, so you could work out where it was at any given time, so get a fix on its position. If it's not interacting with anything else, you'd then just assign it a fixed velocity and just work out where it is at any given time... until it meets another object's grav field, anyhow...

And don't forget the power of parallel processing - if you needed to process 1,000,000 objects per second, get that many processors on it - given the costs of the ships involved, that would be a small price to pay. Also, the process may not be a case of: start this object, process this object, record and move on - it may involve processing multiple objects at once. Remember that we have computers in common use with both decent clock speeds and 8 cores running in parallel (server systems). An expensive TL12 navigation computer would be high up on the state of the art scale for its tech level - it probably would be capable of far more than our current machines to the order where we won't even be able to second-guess it. A Traveller computer has been developed for 100's of years... our current machines have only been developed for 50... just give that a little thought when comparing processing power, guys...

As it happens, I suspect the number of reasonably large objects inside 2 parsecs of each system would not be in the order of trillions... or even billions. Remember that each system would be monitoring for objects around it, so you wouldn't need excessive detail from any of them. Also bear in mind that a CCD of sufficiently high resolution would negate the need for a telescope of any appreciable size, so would make for a larger field of vision.

I just think that a computer of the order of which we're talking could handle far more than you seem to think.

 

[DFW]

Even if it were possible to determine the mass, position, vector and speed
of an object within 1/1000 second (which I tend to consider as impossible)
and with a resulting data collection and processing rate of 1,000 objects
per second it would still take more than 50 years - and the data would be
outdated before the survey would be complete.

I see what you mean. The other alternative is this:

There are x (small number of systems within jump distance) number of paths to watch. Fixed satellites watch those lanes out to several months and report. Problem solved.

 

[phavoc]

We all know a jump last approximately 1 week.
So during the jump, inside jump space, is there any need for a pilot or astorgator to be on the bridge? Is the ship on auto-pilot? What exactly CAN be done IF a pilot or navigators skills are needed while in jump space?
Or is the bridge simply the loneliest place on a ship during jump?
I am setting up a mid-jump scenario and I want to make sure the players (and me as the GM) have a good grasp of crew stations during the jump phase. Obviously nobody should need to be at a weapon station. Engineers will obviously be monitoring the jump drives and power plant. But what about the ships pilot, astrogator, communications, computer ops, etc....
The core book is silent on most conditions within jump space except "Being completely cut off from the rest of the universe"... so is there even a need for my players to be at their crew stations on a bridge?

No, not really. Different versions of Traveller have different jump mechanics. Pre-MGT has jump grids that get charged and take the ship into hyperspace. If your grids suffer a status change, like say a bomb or whatever, it can have dire consequences. I don't recall how the jump drive worked once you got into jumpspace.

Under MGT, the jump drive dumps your fuel into a space around your vessel, and turns the hydrogen into exotic particles. That 'cloud' slowly dissapates, and when it gets down to nothing, you are popped back into n-space at your planned destination. The jump drive only is required to get you into jumpspace, not out.

So there is nothing a pilot or navigator can do except to play solitaire on the ships computer during a jump. I would suspect on ships above a scout-class, that someone would remain on the bridge at all times to monitor ships systems, watch for alarms, and play mineswepper (solitaire gets boring yanno...). Engineers generally have something to do/fix/break all the time, so they'll probably pull regular engineering shifts. And in jump space you can do work on just about every ships system and wherever, so crews are going to be kept busy by the captain doing something.. PC's can brush up on weapons skills, new languages or try out a new version of 3d minesweeper.

Military ships are gonna run like they always do. Officers here and there, ratings doing something, chiefs making sure officers do nothing and ratings do something. For them j-space and n-space should be equally boring.

Also... since it does not cover this in the book, is there ever a chance for an emergency "exit" out of jump space? Say if something went wrong with the engines during day 5 of the jump? How is this handled? Can the ship exist jump space early?
Thanks for any input.

For the most part, no. A ship can be yanked out by flying within 100D of an object, but take that rule with a grain of salt. As others have mentioned, you have asteriods, oort debris and all kinds of stuff out there. And Traveller has always played this rule very loosely. Technically its ANY object... which is why you have to roll when you use drop tanks to jump to see if their being too close affected your jump. In theory, if you can get through the oort cloud, you should be able to jump with droptanks nearby.

So figure out what sort of jump problems you want your players to experience. I personally think that getting into jump you are only affected by massive objects - suns, gas giants, planets, moons, large planetoids, even massive 10million DTon stations. But small objects such as a meteor, another ship, etc? Nah. Makes no sense from a gaming point of view.

And as far a rogue objects between systems. They CAN happen.. and sometimes they are inhabited by space bunnies (FEAR a space bunny from oouuttteerrrr sspppppppaaaaaaccccceeeeee!!!). But unless you are wanting your players to find said space bunnies, just disregard it. If you are pulled out of jumpspace 1ly from your destination, your dead anyway, and nobody will find you for a very long time. There was a CT adventure about a rogue asteriod pirate base that had jump drives and was out in deep space... but it was just a legend. No, really!
Jak[/quote]

 

[Captain Jonah]

Adding to the hijacked bit.

The mass of an object creates a jump shadow, a big enough jump shadow protrudes into jump space and can disrupt jumps. With all the small stuff they simply will not be big enough to put a mass shadow deep enough into jump space to cause any trouble. Anything smaller than small moons or very dense clusters of asteroids will not be noticed.

You can zip straight through the cloud since while there may be trillions of items there none of them have the mass to disrupt a jump.

1km wide rocks simply do not have the mass (normaly) to throw off a gravity well deep enough to enter jump space and disrupt a jump.

Now if people want to make the clouds that dangerous and want small objects to disrupt jumps then thats fine, its your game. But if you can throw off a jump with such a small mass it becomes very easy to disrupt jumps on a military scale. Drag a load of 1km asteroids around to build a wall on the most likely jump route from planet A to planet b and wait for the victims to arrive. Pirates with a decent sized tug spend a few weeks towing a few rocks to the direct route between rich world C and industrial world D. If they only catch 0.1% of the traffic in deep space that is still a lot of loot and ships vanishing without trace. How do you find them, they are sitting in deep space and will need to move every few weeks anyway to remain on the most direct route between the two worlds.

Oh and for people who will say its impossible to do. Nope. You jump from one world to another you will be taking jumping from the 100D limit, that gices you an area roughly a million KM across, you will be plotting a straight run allowing for known hazards and aiming to end up at the 100D limit of the destination world. THis means just about all the ships on that route will be folling the same route through jump space, a tunnel 1 million KM across. That is a big area which makes the pirate trap tiny in comparison but even catching one ship out of every thousand will still net you enough to cover the cost of the tug and the pirate operation. Just set up in the middle of the jump tunnel to catch the most targets and get a good book to read while waiting for the next victim to fall in your lap.

You will need a fair number of asteroids and a lot of luck and maybe net a ship every week or two on even the busy routes but unless you end up catching a passing warship it is far safer than trying to hit ships in a busy system.

 

[locarno24]

I've always used =>1km to have a Jump shadow.

Sounds sensible. Our version is that the object has to be big enough for the entire ship's jump bubble to be within its 100d 'shadow' or it doesn't matter (it's just part of the general unevenness that you have to deal with with when making J-Drive or Jump Control checks). So the object has to be at least 1% of the size of the ship (which still gets rid of most things)

There has to be a minimum size, Otherwise every particle of stellar hydrogen has a tiny jump shadow and you might as well give up on jump technology altogether!

 

[rust]

Our version is that the object has to be big enough for the entire ship's jump bubble to be within its 100d 'shadow' or it doesn't matter ...

Since my new hobby already seems to be picking Traveller's nits ... :roll:

This way an object's jump shadow is based upon its volume, while logi-
cally it should be based upon its mass, because it is the object's gravity
field which influences the jump bubble, not its diameter. Since the avera-
ge density of an object can vary widely (in our system for example Mer-
cury with 5.43 g/ccm and Saturn with 0.69 g/ccm), the volume of an ob-
ject does not necessarily tell much about its mass.

 

[Captain Jonah]

Hey Rust, you can get some good shampoo's and creams to deal with those nits, the chemists are also fairly discrete

That said i fully agree, the jump shadow of an object has to be based on its mass not its size. A gas giant may be huge but the jump shadow it projects is smaller and more shallow in proportion than a solid rock world.

Again this is Traveller being a 1970s RPG about 1770s campaigns using 1950s ideas of tech :lol:

However giving worlds a jump shadow based on 100D is far simpler than allocating a jump shadow and safe jump radius based on mass for every world in every system you may find.