So how often do Jumpships go to Interstellar Mediums?

[Caedis Animus]

See the title. I'm curious about how often Jumpships go to Interstellar Mediums, AKA the space between the stars. Is it often?

[Bosefius]

See the title. I'm curious about how often Jumpships go to Interstellar Mediums, AKA the space between the stars. Is it often?

From everything I've read they rarely, if ever, go. The only way to recharge the jumpship would be to charge off of the battery, which even see a slow trickle has been stated as being dangerous.

I actually just finished re-reading Liberation of Terra, Vol 1 and during the Amaris Coup sooner if the SLDF ships did jump to "Medium" areas. As they charged for a second jump some ships were lost because of damage from charging from the engines.

All of that being said, the SLDF did have some bases hidden in these areas. The base would charge the ships (no, I don't know why that was possible but using the engine was dangerous, maybe the recharging system was specifically built to mimic the power pulled from a sail). After the Exodus Comstar took over one of these bases, Luyten 68-28.

TLDR: very rarely, only in emergencies to flee someone that could cover your suspected destinations

[idea weenie]

In 3025, Jumpships go to empty Interstellar Mediums, if they absolutely know they will be able to make a second jump to safety.  Since most Jumpships are held together with duct tape and crossed fingers, most Jumpships won't do that.

Then you have a few Jumpships (some House vessels, a few major companies) that are in good enough shape to make those jumps, and fewer of those do so repeatedly (and charge a nice fee for the capability).

And then there's Comstar.  Their Jumpships are in good shape, but there's only a few of them.  So if you need reliable shipping capacity to your hidden base, they are the ones to talk (and pay lots of money) to.


As to recharging, engines can have small spikes in their power output that isn't an issue with weapons fire, but the Jump Core will complain about.  By using Batteries you can have a smooth power output to avoid the KF Core barfing itself all over.  What likely happens is the base uses a small fusion power plant to recharge the batteries, and then the batteries to charge any nearby KF vessels.  Also by using recharge batteries, you get a discount to the time needed to recharge (IIRC +2 on the success roll, offsetting a -2 on the roll for using 150 hrs instead of 175).  This could be due to recharging producing heat in the KF core, and the direct connection allows using the station's heat sinks for coolant, instead of just the Jumpship's.

A comparison would be the Liquid Mirror telescopes in use today.  They use a reflective liquid (mercury, gallium, or silver in a glycol solution) in a flat pan, and the pan is spun.  The spinning liquid forms a parabola shape.  However small power surges from the power lines will distort the spin rate enough to make the images blurry.  By charging batteries and running the spin motor off the batteries this small fluctuation is removed.


KF cores are poking holes in the universe to get to the other side.  You don't want to make a mistake.

[Tai Dai Cultist]

KF cores are poking holes in the universe to get to the other side.  You don't want to make a mistake.

As a tangent, I've always thought that movie could work as a movie produced within the BTU.

And/or it serves as an excellent kernel upon which to build a ATOW scenario...

[Charistoph]

As to recharging, engines can have small spikes in their power output that isn't an issue with weapons fire, but the Jump Core will complain about.  By using Batteries you can have a smooth power output to avoid the KF Core barfing itself all over.  What likely happens is the base uses a small fusion power plant to recharge the batteries, and then the batteries to charge any nearby KF vessels.  Also by using recharge batteries, you get a discount to the time needed to recharge (IIRC +2 on the success roll, offsetting a -2 on the roll for using 150 hrs instead of 175).  This could be due to recharging producing heat in the KF core, and the direct connection allows using the station's heat sinks for coolant, instead of jump the Jumpship's.

A comparison would be the Liquid Mirror telescopes in use today.  They use a reflective liquid (mercury, gallium, or silver in a glycol solution) in a flat pan, and the pan is spun.  The spinning liquid forms a parabola shape.  However small power surges from the power lines will distort the spin rate enough to make the images blurry.  By charging batteries and running the spin motor off the batteries this small fluctuation is removed.

Computers also have similar situations today, they just are a little more tolerant in the short term.  Most servers are set up with uninterruptible power supplies (UPS) with automatic voltage regulation (AVR) specifically to deal with this problem.  The UPS is capable of using this AVR to ensure a consistent energy flow with a minimum of spikes and valleys.  Its ability to lengthen the processing life of the hardware is huge when compared to the cost of implementation and replacement.

It's not even advanced tech today (though, I can't say for the 1980s), as you can get such a box for your home equipment from almost any electronics store.

[CrazyGrasshopper]

To begin with, not every JumpShip has enough fuel to recharge from a power plant, it requires around 10 burn-days of fuel. And those that can are not the most numerous ones, for example Invader, Star Lord and Monolith can't. Magellan can, but Magellan is the JumpShip for long-range missions. The process itself is not very dangerous and it was the standard for early JumpShips. In fact, if you are not quick-charging, you will not damage the drive.

If you want an example from fiction, in the beginning of A Bonfire of Worlds JumpShips were in interstellar medium, though not very far from their destination.

[Caedis Animus]

As a tangent, I've always thought that movie could work as a movie produced within the BTU.

And/or it serves as an excellent kernel upon which to build a ATOW scenario...

Off topic, but it'd actually fit a lot more with Warhammer 40K than Battletech.

[Death by Lasers]

  Just to add to what is being said I don't think it happens often (if ever). 

  First, as has been said by GrazyGrasshopper, most jumpships do not have the fuel reserves to jump using their fusion reactor.  In other words if they don't have a star they can't jump.  Unless the jumpship has an HGP (very rare in all eras) then it is effectively dead as they can't communicate their position to anyone and they have no star to recharge their jump drives.  So for most jumpships the void between stars is a death sentence.

  Second, there should be plenty of uninhabited star systems between every habitable one.  It's a little tricky to figure out how many because Btech is a 2D Star map representing 3D space (I just assume jump drives have either unlimited or a fixed "horizontal" jump span that costs no light years its jump distance, but its a fan theory).  Depending on how you interpret the jump map I would say that their are anywhere from tens to thousands of empty star systems surrounding each habitable one.  So if you want to sneak through enemy space just pick one of the many "empty" star systems to charge from.

[roosterboy]

All of that being said, the SLDF did have some bases hidden in these areas. The base would charge the ships (no, I don't know why that was possible but using the engine was dangerous, maybe the recharging system was specifically built to mimic the power pulled from a sail). After the Exodus Comstar took over one of these bases, Luyten 68-28.

Luyten 68-28 is a star system, though, not a location in the interstellar medium.

[Ice_Trey]

Also, If I'm understanding things right, the stars that we see in the Inner Sphere starcharts aren't the only stars out there, but are rather the inhabited systems. There are likely to be uninhabited star systems between them, but even in times of war, Jumpship captains avoid using those, because if they suffer any damage or a misjump, nobody's going to come to the rescue.

[Terminax]

I'll never understand the silliness of how the power to charge a K-F drive comes from can damage the drive. Electricity is electricity and the potential for fluctuations between charge from a fusion reactor or solar sails should be about the same. The only difference should be in the consumption of reactor mass.

[worktroll]

Also, If I'm understanding things right, the stars that we see in the Inner Sphere starcharts aren't the only stars out there, but are rather the inhabited systems. There are likely to be uninhabited star systems between them, but even in times of war, Jumpship captains avoid using those, because if they suffer any damage or a misjump, nobody's going to come to the rescue.

Very much this, on both points. There'll usually be a star somewhere near where you want one, but if you do have a problem, you're toast.

[guardiandashi]

I'll never understand the silliness of how the power to charge a K-F drive comes from can damage the drive. Electricity is electricity and the potential for fluctuations between charge from a fusion reactor or solar sails should be about the same. The only difference should be in the consumption of reactor mass.

its a "setting feature" for anyone with even a small amount of electricity/electronics knowledge it breaks down to BS very abruptly but it is what it is.

heck based on the energy requirements, and the fact that you are charging up a battery/Capacitor that then powers the jump core the better answer is even simpler and I find the people in universe "stupid" for not thinking of and using it. 
you hook a standard vehicle fusion reactor likely even in the unit still up to an "input line" to the KF drive batteries, and use that "small" stabilized power source to charge the KF power system at a slow and "safe" rate.

[ANS Kamas P81]

Very much this, on both points. There'll usually be a star somewhere near where you want one, but if you do have a problem, you're toast.

True, but "somewhere near" means it takes years for your distress message to get heard...and you only have a few months of consumables onboard.  That said?  Picking up a message from a jumpship that ended up in the Deep that had some kind of valuable cargo onboard, and sending your PCs to investigate would totally work.  Especially when there is a survivor or two after all this time.

[worktroll]

Great adventure hook, yes. Great campaign planning, probably not. :)

(And yes, the 'Event Horizon' scenario writes itself ...)

[CrazyGrasshopper]

I'll never understand the silliness of how the power to charge a K-F drive comes from can damage the drive. Electricity is electricity and the potential for fluctuations between charge from a fusion reactor or solar sails should be about the same. The only difference should be in the consumption of reactor mass.

its a "setting feature" for anyone with even a small amount of electricity/electronics knowledge it breaks down to BS very abruptly but it is what it is.

heck based on the energy requirements, and the fact that you are charging up a battery/Capacitor that then powers the jump core the better answer is even simpler and I find the people in universe "stupid" for not thinking of and using it. 
you hook a standard vehicle fusion reactor likely even in the unit still up to an "input line" to the KF drive batteries, and use that "small" stabilized power source to charge the KF power system at a slow and "safe" rate.
[/quote]

I did not get what both of you meant. Using reactor to charge does not damage the drive, as per rules in SO p.87. You can damage the drive if you are quick-charging, but the source of power does not affect the damage in any way.

And how what you proposed differs from using the power plant?

[guardiandashi]

its a "setting feature" for anyone with even a small amount of electricity/electronics knowledge it breaks down to BS very abruptly but it is what it is.

heck based on the energy requirements, and the fact that you are charging up a battery/Capacitor that then powers the jump core the better answer is even simpler and I find the people in universe "stupid" for not thinking of and using it. 
you hook a standard vehicle fusion reactor likely even in the unit still up to an "input line" to the KF drive batteries, and use that "small" stabilized power source to charge the KF power system at a slow and "safe" rate.


I did not get what both of you meant. Using reactor to charge does not damage the drive, as per rules in SO p.87. You can damage the drive if you are quick-charging, but the source of power does not affect the damage in any way.

And how what you proposed differs from using the power plant?

because using the jumpships fusion reactor "somehow" burns 10 burn days worth of fuel when using the 300 rated fusion reactor would burn a couple kg of fuel to generate the needed energy to charge the drive.

someone (I think it might have been Cray) did the calculations although I think it was also stated that pathfinder the original jumpship, used about 1 megawatt to fully charge its jump core, basically the argument is that as listed the jumpships stationkeeping drive, could generate all the energy needed to charge the jump core in a matter of seconds or minutes. granted the jump system can't take it that fast, or BAD THINGS^tm happen.  my argument was more that if you took the power from a mechs fusion reactor which generates something approaching the required power levels (while still being significantly higher) IE lets say a 50 rated fusion reactor can out 50mw/s IE the rating on the engine table is ~its mw/s output equivalent so that 300 rated reactor in your marauder has the same output as a 300MW powerplant from today then its a lot more "efficient" use of the fuel because you are only producing say 100-1000 times as much power as needed not a million times as much.

[CrazyGrasshopper]

because using the jumpships fusion reactor "somehow" burns 10 burn days worth of fuel when using the 300 rated fusion reactor would burn a couple kg of fuel to generate the needed energy to charge the drive.

someone (I think it might have been Cray) did the calculations although I think it was also stated that pathfinder the original jumpship, used about 1 megawatt to fully charge its jump core, basically the argument is that as listed the jumpships stationkeeping drive, could generate all the energy needed to charge the jump core in a matter of seconds or minutes. granted the jump system can't take it that fast, or BAD THINGS^tm happen.  my argument was more that if you took the power from a mechs fusion reactor which generates something approaching the required power levels (while still being significantly higher) IE lets say a 50 rated fusion reactor can out 50mw/s IE the rating on the engine table is ~its mw/s output equivalent so that 300 rated reactor in your marauder has the same output as a 300MW powerplant from today then its a lot more "efficient" use of the fuel because you are only producing say 100-1000 times as much power as needed not a million times as much.

I see. So, basically, you are claiming that the canon fuel consumption is over-inflated. What was the reasoning for that? The minimum power output can't be controlled?

EDIT: Wait. Why is the energy measured in watts? And how much energy is needed to charge the drive? How does it scale with mass/size of the ship? Was the the amount of energy needed based on the amount of energy the jump-sail would collect?

[Bosefius]

Luyten 68-28 is a star system, though, not a location in the interstellar medium.

Maybe it was Freedom Station. Funny enough, the book says people get them confused all the time.

[SCC]

I see. So, basically, you are claiming that the canon fuel consumption is over-inflated. What was the reasoning for that? The minimum power output can't be controlled?

EDIT: Wait. Why is the energy measured in watts? And how much energy is needed to charge the drive? How does it scale with mass/size of the ship? Was the the amount of energy needed based on the amount of energy the jump-sail would collect?

Because long ago FASA decided that JS burn their drives all out (For simplicity) when they are used, even when having the drive going really makes no sense, so the burn days thing was used for charging from the drive. Doesn't make it any better, the amount needed the charge the drive is basically nothing and should probably be included in what's needed to keep the lights on and air circulating.

[Colt Ward]

Bluntly, going to a uninhabited star should not be a big deal for large force movements . . . its when your ship is solo it can get nerve rattling.  The other side is some of those could have outposts that do not qualify for the map as 'colonies' or 'settled worlds' because they are science stations, temporary mining sites or even military R&D or listening posts.

[marauder648]

Kind of related to this.

I assume the standard 24hrs of charging is for a Sol like sun, would this be extended at stars with weaker outputs like red dwarfs or shortened at a more luminous and brighter star?

[Frabby]

I assume the standard 24hrs of charging is for a Sol like sun, would this be extended at stars with weaker outputs like red dwarfs or shortened at a more luminous and brighter star?

24hrs would be a quickcharge.

The average recharge time is around 170 hours or ~ 7 days, give or take. Which conveniently happens to be around the time it takes for a DropShip to make the trip between jump point and habitable planet. That is to say, when you lift off to reach a newly arrived JumpShip, you'll arrive there just about when they have finished recharging.

There are tables in various rulebooks depicting the safe recharging time via jumpsail at a regular (zenith or nadir) jump point for different star types. The list goes from 151 hours for a B0 class star to 210 hours for an M9 class star.

I'm pretty sure that the table assumes you're sitting at the jump point right beyond the proximity limit, and that recharge time gets longer when you're further out from the star. I can't provide a reference right now though. In deep space (interstellar medium as per OP), there is no nearby star so you effectively can't recharge via jump sail.

[marauder648]

O_o 7 days! I thought it was like 24 hours..wow I really need to look up stuff more :p

[Frabby]

O_o 7 days! I thought it was like 24 hours..wow I really need to look up stuff more :p

Are you German? Because I noticed that several German authors apparently believe recharging is much faster than it actually is. But as far as fully canonical sources are concerned, nope, regular jump sail recharging takes around 7 days.

[marauder648]

Are you German? Because I noticed that several German authors apparently believe recharging is much faster than it actually is. But as far as fully canonical sources are concerned, nope, regular jump sail recharging takes around 7 days.

Actually i'm English :p

[Nebfer]

The Generic recharge rate is 175 hours which is basically 7.3 days, which allows for 50 jumps per year or 1,500 x C (C=light speed), If one has continued access to a recharge station and used that (and particularly used the hard line, rather than wireless) one could shave about a day off that time (~150 hours) to about 6.25 days, which adds about 240 light years to B-techs FTL (Faster Than Light) speed (total jumps rises to about 57-58 (depending how long you take for docking and clearing the station)).

[Giovanni Blasini]

For Trekkie perspective, 1500c works out to over Warp 11 in the TOS/ENT "OCU" scale, and just shy of Warp 9 in the TNG+ "MCU" scale.

Jump drives aren't actually that slow compared to some of the other sci-fi conventions out there.

[Maingunnery]

For Trekkie perspective, 1500c works out to over Warp 11 in the TOS/ENT "OCU" scale, and just shy of Warp 9 in the TNG+ "MCU" scale.

Jump drives aren't actually that slow compared to some of the other sci-fi conventions out there.

Indeed, BT cruise speeds are pretty good, especially if one has LF batteries.

[Charistoph]

Indeed, BT cruise speeds are pretty good, especially if one has LF batteries.

That's really not a "cruise" speed...

[Giovanni Blasini]

Sure it is: JumpShips could actually go faster quick-charging their drives.

[CrazyGrasshopper]

Come to think about it, Belters that live in the Oort Cloud are effectively in interstellar medium. And JumpShips that they use just have to charge from their reactors.

[worktroll]

True, but if a ship has a problem, they can holler for help, and expect to get it before the O2 runs out ... hopefully ;)

[Colt Ward]

Come to think about it, Belters that live in the Oort Cloud are effectively in interstellar medium. And JumpShips that they use just have to charge from their reactors.

I actually meant to point this out . . . no.  You will have solar energy reach everywhere . . . just is it useful quantities to recharge in a timely manner?

[worktroll]

Short answer, no. In the Oort cloud, the Sun is just a very bright star. Solar charging will not be a viable option.

[CrazyGrasshopper]

I actually meant to point this out . . . no.  You will have solar energy reach everywhere . . . just is it useful quantities to recharge in a timely manner?

There won't be enough energy. The density of the radiated energy decreases as the square of distance. The Oort starts in about 1000 AU from Sun, it's effectively in interstellar medium.

[Stinger]

I'm an engineer and I love the physics talk as much as the next guy, but holy cow you guys just murdered a whole crop of cat girls.

[worktroll]

Catgirls don't belong in vacuum.

Remember, Fasanomics works if you assume that for every citizen of the Inner Sphere, there's a catgirl. But they're all too embarrassed to talk about them, which is why they don't appear in fiction, except for Niops. Thats' where all the extra economic production is sunk.

[ANS Kamas P81]

Canon In Canopus!

[Kit deSummersville]

These days most JumpShips go to Interstellar Extra Larges.

[Kovax]

A "medium" is one who can communicate with the spirit world, so an "Interstellar medium" would be a fortune-teller in space.  The Jumpships may not go to Interstellar Mediums, but the captains and crew might visit one on occasion.

[Tai Dai Cultist]

A "medium" is one who can communicate with the spirit world, so an "Interstellar medium" would be a fortune-teller in space.  The Jumpships may not go to Interstellar Mediums, but the captains and crew might visit one on occasion.

You're right, because the plural form of the other kind of medium is media.  The title doesn't ask how often do JumpShips enter Interstellar Media.

[kato]

In-universe, historically, we have 15-light-year KF drives as the eminent jump system. If you look at a map of the inner Inner Sphere, 15 LY jumps tie you down to specific routes to a large extent if you only use settled systems; for example, about any route from Terra anti-spinward - and there's a large number of early colonies there - would run via New Earth.

One could also deduct that the early spread and ubiquitous installation of recharging stations specifically along such routes - read: about every settled system in the early colonization phase - means that these routes were also used predominantly for shipping; that other avenues - unsettled systems or interstellar medium, even non-standard jump points in-system - tended to be pretty much a negligible factor can be seen largely in the fact that canonically, troop convoys are attacked at known jump points throughout the next millenium.

[Caedis Animus]

I completely misread a comment. Or actually left off a sentence when I read it.

[elf25s]

in bt universe ships do not go out too often into the interstellar void...
they go to already scouted and routed points
as far as i remember the only exception to that rule on regular basis would be explorer corps

[glitterboy2098]

even explorer corps mostly jumps to points above/below stars. they just don't know what is around said stars till they get there.

[Frabby]

Jumping into the void between the stars can be unnerving, as you're left without a reference point for lightyears in all directions.
A canon example of a JumpShip going there is the BC story Echoes in the Void. So it does happen.

I reckon, though, that the most frequent reason for JumpShips going into deep space far from any star system would be misjump where they miss their destination jump point by a light-year or more. So involuntarily and by accident; not that there's any good reason to go there.

[Frabby]

Jumping into the void between the stars can be unnerving, as you're left without a reference point for lightyears in all directions.
A canon example of a JumpShip going there is the BC story Echoes in the Void. So it does happen.

I reckon, though, that the most frequent reason for JumpShips going into deep space far from any star system would be a misjump where they miss their destination jump point by a light-year or more. So involuntarily and by accident; not that there's any good reason to go there.