Questions: Inner Sphere Map and Dropships

[Vorpalstar]

Hi, I'm continuing to learn about the BattleTech Universe, and this week I have some questions about the Inner Sphere Universe Map and dropships.

For the Inner Sphere Map
Do the locations on the Inner Sphere map represent individual planets or star systems potentially containing multiple planets?
Are these the only locations, or does the universe allow for undiscovered or hidden locations?

Now on to dropships.
I am going to guess that in most cases a jumpship or warship doesn't just jump into a system right next to a planet and launch dropships directly down to said planet in a matter of minutes. My thought is that this would be a very dangerous course of action because of the potential for planetary defense weapons. Is this line of thought correct?

With that said, is there an average transit time (days? weeks?) for dropships to reach their planetary landing area?

Thanks!

[monbvol]

Star systems, sometimes even entire star clusters.

And yes there is plenty of stuff for inserting your own worlds and undiscovered/uninhabited worlds.  I would recommend Interstellar Expeditions as a reasonable guide for what you can expect in this regard.  If you feel ambitious there is even rules in A Time of war Companion(somewhat simplified but still can be a bit daunting) and Interstellar Operations(there be math here) for creating your own systems.

As for your second question the answer is yes but not for the reasons you already point out.  There is a maximum amount of gravity that jumpships and warships can jump in and out of.  If you have really accurate charts of a system you can use what are known as pirate points.  They are a bit riskier than the standard Zenith/Nadir points used due to potential damage to the jump core and debris that can orbit through resulting in potential collisions.

For the most part you can assume a week for transit times from jump point to planet, or vice versa.  If you really want to get into the details it does vary by star type and there are charts out there that describe such things.

Hope this helps.

[Revanche]

Vorpalstar,

Frabby discovered an in-universe 'rule' for system-naming that helps support this. In BattleTech: 25 Years of Art & Fiction (p. 47), there is this quote in the Rosetta planetary sidebar:

Per convention, the system is named after the habitable world, Rosetta.

At Sarna, we've taken that as guidance for the Planets project, as has the Sarna Unified Cartography Society team for their SUC Kit.

Also, the transit time chart monbvol cites can be found in Campaign Operations (p. 100, 102-PDF) (as well as other places). I don't think those have been changed at any point since their first release in a far earlier title.

Hope that helps.

[BradGB]

Informations about the Starsystems can be found in Sourcebooks, Housebooks and other puplications.
you can find them collected at Sarna or at ISAtlas.teamspam.net

[Vorpalstar]

Hope this helps.

Hope that helps.

This does help point me in the right direction, and it also tells me I am going to need to do some more reading. Which also means, I am going to need some new books.

Thanks much!

[guardiandashi]

to the best of my knowledge the transit times and jump tables were originally in at1, or dropships and jumpships,  with that said the basic standard jump point distance is set by the stellar class of the star(s) of the star system. Our solar system is a G3 if I am remembering right, so you cross reference that and it says the zenith, and nadir as well as the general "safe" jump distance is set by that, which I want to say is something like 1.33 billion km, or roughly the orbit of Saturn closer than that and the gravity well is too "steep" for the KF drive to work (unless at a "pirate point" ) as mentioned.  the transit time is ~8.5 days at 1g.

[monbvol]

Sol is a G2V.

[Vorpalstar]

Ok I was taking a look at some of the entries on Sarna and the Inner Sphere Atlas, and I noticed that not all of the systems are fully developed. I'm guessing that is because some degree of creative license is left up to each individual gaming group.

Regarding Transit Times / Jump Point Distance or as IS Atlas calls it Time to Jump Point, is this the travel time to reach the planet? Does this time apply equally to all sizes of a craft? What I'm asking is, for example Tharkad has a Time to Jump Point distance of 7.01 days, is this travel time the same for dropships, small craft, and warships / jumpships? I'm going to assume it is an average travel time, and that ship speed will vary.

Thanks again.

[Daryk]

The "time to jump point" assumes a transit at a steady 1G acceleration (turning over half-way there to slow down again).  Jumpships generally don't make that transit.  It's not that they can't, it's just that there's no reason to (and it would be a bit slower, since they only have station keeping drives capable of a fraction of a G).

[glitterboy2098]

Ok I was taking a look at some of the entries on Sarna and the Inner Sphere Atlas, and I noticed that not all of the systems are fully developed. I'm guessing that is because some degree of creative license is left up to each individual gaming group.

pretty much. there are so many stars and worlds in the setting that trying to flesh out every single one would be a huge undertaking. so generally the writers try to research what has been mentioned before, for consistency, and fill in details as they go when they are using worlds with no or little info. Sites like sarna.net are a big help there.

as a player or gamemaster, i would suggest the same approach. look up the name fro mthe map you are using. if there is info already, use that, if not, make up whatever fits your needs.

though it is also worth noting that the maps only show the major inhabited worlds and. there are a lot of stars with no worlds between them, or stars with worlds with populations too small or too unimportant to matter. so you don't actually have to travel through the named worlds on the map. (it is just how people in the setting prefer to travel, because if you use the stars that aren't inhabited, and something goes wrong with your ship, you could be stranded there. sticking to the major worlds (the ones shown on the game's maps) means that if, for example, your jumpship blows a seal on its jump core coolant system, and isn't able to jump any more, you can contact the world and ask comstar to send a message requesting help/spareparts be sent. and if your drive fails entirely, you aren't stranded in an uninhabited or barren system to die.)

Regarding Transit Times / Jump Point Distance or as IS Atlas calls it Time to Jump Point, is this the travel time to reach the planet? Does this time apply equally to all sizes of a craft? What I'm asking is, for example Tharkad has a Time to Jump Point distance of 7.01 days, is this travel time the same for dropships, small craft, and warships / jumpships? I'm going to assume it is an average travel time, and that ship speed will vary.

Thanks again.

yes it will be the same for smallcraft, dropships, and warships. when transiting over large distances, ships usually travel at an acceleration of 1g (1 gravity, aka per second^2), as a result the travel times will be identical. ships can accelerate faster (anywhere between 1 and 2g's typically) if their drives are powerful enough, which can reduce that time by a fair amount, but going more than 1g means the crew and passengers are put under a lot of stress (imagine spending days inside one of those amusement park spinning rides, like a gravitron.. and trying live and work under such 'pull'.)

jumpships are the exception here, because their drives are so much weaker.. about 1/10th of a g, which means that instead of a week, to go from terra to the jump point, it would take a couple months. as a result jumpships rarely leave the jump points, instead just waiting at the points and letting their dropships and smallcraft make the trips back and forth.

[Daryk]

Station keeping drives are one-tenth of a G, but the difference in travel times isn't that bad.  It's only a factor of the square root of ten (~3.16), so your example one week transit at 1G would only become a little over three weeks (Strat Ops, page 259 refers).

[Vition2]

For the Inner Sphere Map
Do the locations on the Inner Sphere map represent individual planets or star systems potentially containing multiple planets?
Are these the only locations, or does the universe allow for undiscovered or hidden locations?

To add a little bit to what others have already said regarding your first question, in addition to each representation potentially indicating a system or cluster of inhabited planets, there are a couple of instances where a single system is represented by multiple pips.  Notably the Mica Majority grouping and the Niops Association grouping, both are singular systems with three inhabited planets and each inhabited planet is represented by a pip.  Most other systems, regardless of the number of inhabited planets within are represented by a single pip, the primary example for this is Terra, where there are at least three major inhabited planets (and kind of a fourth), Terra itself, Luna, Mars, and Titan (pop: 300 as of the end of the Jihad).

[VhenRa]

To add a little bit to what others have already said regarding your first question, in addition to each representation potentially indicating a system or cluster of inhabited planets, there are a couple of instances where a single system is represented by multiple pips.  Notably the Mica Majority grouping and the Niops Association grouping, both are singular systems with three inhabited planets and each inhabited planet is represented by a pip.  Most other systems, regardless of the number of inhabited planets within are represented by a single pip, the primary example for this is Terra, where there are at least three major inhabited planets (and kind of a fourth), Terra itself, Luna, Mars, and Titan (pop: 300 as of the end of the Jihad).

During Star League Era it also had another inhabited planet in the system, Venus.

[Mendrugo]

There was also a mining operation on the dark side of Mercury, a resort on the moons of Saturn, and thousands of small settlements in the asteroid belt and Oort cloud (the Belters).

[Vorpalstar]

Wow! Thanks to everyone for their help and pointing me in the right direction here.

I'm getting the impression that space travel in the BT universe works much different than in more mainstream SciFi like StarWars.

I'm thinking I will need to pick up some of the more advanced rule books to really get the details. Or most likely buy the PDFs, as hardcovers seem to be hard to find or way overpriced.

[Vition2]

The closest other SciFi FTL to BattleTech I can think of is space folding - though it's not that.  Travel between stars is done via jumpships which can jump from one area of low gravity to any other area of low gravity within ~30 light years (much older ships can be more limited, while only one or two ships - not classes, individual ships - can go much further).  Basically a jumpship teleports from one location to another without actually using a movement drive.

[Dragon Cat]

BT is different the zero g without thrust alone makes for different encounters in space

The jump system is more akin to the nBSG style than Star Wars or Star Trek though BSGs is more advanced.  In BT you have the slow with fast slow to recharge the system then the fast jumping from one system directly into the next unlike other sci-fi which travels through that dark space between

I'll note that JumpShips and WarShips CAN jump into the void between systems but it's risky since damage to your drive can end with you stuck in the void with a very long trip home

[glitterboy2098]

FTL in battletech is very similar to the Alderson Drive from Niven and Pournelle's "A Mote in Gods Eye".. which has a lot of other setting similarities as well.

the difference is that the Alderson Drive's jump point are apparently random spots inside a solar system, and only go to one other system, while BT's jump points are fairly standard locations, and allow a jumpdrive equipped ship to go anywhere within it's jump range.

[Kovax]

A jump drive in the BT universe can't operate in a high gravitational field, and even with a relatively small gravitational effect, it needs to be compensated for.  If you jump to a random point in the system without proper compensation for gravity, the gravitational pull will distort the jump "envelope", potentially scrambling or warping the arriving jumpship, with catastrophic results for the crew.

The ideal way to compensate for gravity is to find a gravitational null point, which means that all gravitational sources cancel.  Unfortunately, with planets constantly shifting around, those points will drift, and may appear and disappear over time, making them difficult to use, and impossible without a lot of prior mapping and advanced calculations.  These are often referred to as "pirate points".

The most stable and usable way to deal with gravity is to jump to a point along the central axis of the entire solar system, where all of the other complex planetary interactions can be treated as a single vector running through the star at the center, and compensate for the gravity in the jump calculations.  The two commonly used jump points (both directly above the star - "zenith" - and below it - "nadir") would be at a far enough distance away from the star not to completely prevent the jump due to gravity, with the single gravitational vector of the entire system easily worked into the calculations.  In truth, it's not a "point", but a line extending out from the rotational axis of the star system, where anything beyond some minimum distance from the star itself is "fair game".  Jumping further out means a longer transit time to the planets, so most ships will jump to somewhere not too far beyond the safe minimum point.  Since the planets orbit at fairly consistent distances from the star (slightly elliptical orbits), the transit times from the central axis out to the destination planet will only vary by a few percent over the course of an orbit (that planet's "year").

While the dropships and small craft make their 1G burns to and from the planets (the 1 G of thrust providing the equivalent of normal Terran gravity for the convenience and health of the passengers), the jumpship will avail itself of the light energy from the star (unfurling a massive "light sail" of solar cells) to recharge its jump drive for the next jump, and expend just enough thrust (through a large central hole in the light sail) to keep from drifting any closer to the star.

[Iron Mongoose]

Mechanically I can't add to what's been said.  I think the main point is, that's very slow, relative to most other science fiction that features faster than light travel (though it's dramatically faster than slower than light travel).  Since the base line average is a week from a planet to a jump point (though depending on the star it can very from a day or two to nearly a month for ultra massive stars), even traveling to a world just one jump away takes two weeks.  Any further, add in a week to recharge your jump drive, so going 60 light years (or even just 31) will take three weeks (on average).

Now, of course, for both in character reasons (wealthy nobles don't like to sit around, and important military units need to get to the front) and out of character reasons (the story get's pretty dull if it takes a year to get any place) there are plenty of short cuts: 

Pirate points in system cut transit time, allowing for either short trips and/or military surprise, at the expense of a slight risk of your jump ship being torn apart by gravity or being lost into the void (or eaten by hyperspace monsters, which may or may not be a real thing). 

Command circuits of jump ships allow a dropship (or group there of) to be passed from one spent jumpship to a waiting charged one, over and over again, and cut a trip lasting weeks into one lasting hours, if you have access to a massive number of jumpships with nothing better to do (being Lord of a Successor State helps here, though it's not essential). 

And in a pinch, you can 'quick charge' your jump drive, cutting seven days down to just a part of a single day, but again there's a chance of being lost to the void if you do, so that's mostly reserved for the desperate. 

[worktroll]

If you're looking for parallels in gaming, the Traveller game's FTL works pretty similarly. BT has one thing many 'jump based' systems don't - FTL comms independant of ships, the HyperPulse Generator.

The HPG works in a related but different means to Kearny-Fuchida jump drives. It can be used inside a gravity well, and sends a 'packet' of EM energy via hyperspace. This emerges above the target destination, where it's then picked up by regular radio telescope type arrays. Until later in the piece, HPG messages don't work 'realtime' - the station collects a day's worth of messages, and squirts them on schedule.

Due to cost, complexity, and the connivance of the local Phone Company ;) HPGs aren't on every planet. There's a network of major stations (class A) on major worlds, feeding down trunks (class B & C stations). Worlds off the 'trunks' then rely on JumpShips carrying information packets to and fro.

[guardiandashi]

Mechanically I can't add to what's been said.  I think the main point is, that's very slow, relative to most other science fiction that features faster than light travel (though it's dramatically faster than slower than light travel).  Since the base line average is a week from a planet to a jump point (though depending on the star it can very from a day or two to nearly a month for ultra massive stars), even traveling to a world just one jump away takes two weeks.  Any further, add in a week to recharge your jump drive, so going 60 light years (or even just 31) will take three weeks (on average).

Now, of course, for both in character reasons (wealthy nobles don't like to sit around, and important military units need to get to the front) and out of character reasons (the story get's pretty dull if it takes a year to get any place) there are plenty of short cuts: 

Pirate points in system cut transit time, allowing for either short trips and/or military surprise, at the expense of a slight risk of your jump ship being torn apart by gravity or being lost into the void (or eaten by hyperspace monsters, which may or may not be a real thing). 

Command circuits of jump ships allow a dropship (or group there of) to be passed from one spent jumpship to a waiting charged one, over and over again, and cut a trip lasting weeks into one lasting hours, if you have access to a massive number of jumpships with nothing better to do (being Lord of a Successor State helps here, though it's not essential). 

And in a pinch, you can 'quick charge' your jump drive, cutting seven days down to just a part of a single day, but again there's a chance of being lost to the void if you do, so that's mostly reserved for the desperate.

actually depending on the "sci-fi" ftl rules battletechs jumps can be comparable to nominally faster ftl systems.
to use star trek for a moment because most people are at least somewhat familiar with it....

in a race for up to 30 LY distance a jumpship is going to win, automatically if its jump drive is already charged because the jump is effectively instantaneous for the actual travel.  wheras the starship if its warping has to spend light years divided by ly/h rate to determine how long it spends getting there. for example lets say that the starship runs at 1000x lightspeed this means if it just takes off in a direction in 1 year it will have traveled up to 1000 light years.  the jumpship with averaging 1 jump per week, can travel 1560 light years in the same time meaning its "effective" speed is 1560ly/y over the same time or ~1560x lightspeed.

[Vorpalstar]

The two commonly used jump points (both directly above the star - "zenith" - and below it - "nadir") would be at a far enough distance away from the star not to completely prevent the jump due to gravity, with the single gravitational vector of the entire system easily worked into the calculations.  In truth, it's not a "point", but a line extending out from the rotational axis of the star system, where anything beyond some minimum distance from the star itself is "fair game".

Wouldn't there be some risk of ships jumping into a system colliding with (jumping into) a ship already in system? What about fleet travel?
Does anyone control this traffic?

[Vorpalstar]

Command circuits of jump ships allow a dropship (or group there of) to be passed from one spent jumpship to a waiting charged one, over and over again, and cut a trip lasting weeks into one lasting hours, if you have access to a massive number of jumpships with nothing better to do (being Lord of a Successor State helps here, though it's not essential). 

I'm picturing here an intergalactic network that connects main trade hubs throughout the Inner Sphere for the movement of trade goods and wealthy passengers along an almost regular scheduled route. Almost like airports connect us on modern real life Earth.

[Vorpalstar]

If you're looking for parallels in gaming, the Traveller game's FTL works pretty similarly. BT has one thing many 'jump based' systems don't - FTL comms independant of ships, the HyperPulse Generator.

I just did a quick read about HPG on Sarna.net, and it sounds like a very controlled network for communication.

Does HPG allow for encrypted military traffic? Are there risks of a message being intercepted?
Is Comstar an Intergalactic Big Brother?

Sorry for all the questions, just interested in how things work and some of the fluff behind it.

[Iron Mongoose]

I'm picturing here an intergalactic network that connects main trade hubs throughout the Inner Sphere for the movement of trade goods and wealthy passengers along an almost regular scheduled route. Almost like airports connect us on modern real life Earth.

It's unclear how much this is true, because the number of jumpships is very unclear.  In general, while it's clear that the old number from the 80s (2000 total ships for five trillion people) is wrong, it is also clear that there are never quite as many jumpships as needed, and the facilities to correct that deficiency are all lostech, and can't really respond to usual supply and demand laws.

I just did a quick read about HPG on Sarna.net, and it sounds like a very controlled network for communication.

Does HPG allow for encrypted military traffic? Are there risks of a message being intercepted?
Is Comstar an Intergalactic Big Brother?

Sorry for all the questions, just interested in how things work and some of the fluff behind it.

Yes, it is very controlled, and yes, ComStar makes Big Brother look benign (at least from the 2800s through 3052) since they actively hunted down and killed those who threatened their technological monopoly. 

As to interception, only ComStar (or their splinter group the Word of Blake; that's too long a discussion to have here) could do that in meaningful terms.  Now, they do intercept everything that passes through their hands, but there's no way another power could, aside from having infiltrating ComStar (not unknown, but very rare).

As to encrypted military messages, they are possible and there is precedent (Justin's coded message to his father in the Warrior books, for example), but ComStar's code breakers are the best, and since they guarantee security historically there was little need.  You could send a plain text to your commander at the front "move the troops to planet X" and be confidant that the message would go through and your enemies would never see it.  Post 3052 it's a bit more complicated, and post 3085 I don't really clearly know, but again a longer discussion than belongs here. 

[SCC]

There was also a mining operation on the dark side of Mercury, a resort on the moons of Saturn, and thousands of small settlements in the asteroid belt and Oort cloud (the Belters).

Mercury is in a resonate orbit - no dark side. And I'm pretty sure that this had been know for at least 10 years then BT was first released.

FTL in battletech is very similar to the Alderson Drive from Niven and Pournelle's "A Mote in Gods Eye".. which has a lot of other setting similarities as well.

the difference is that the Alderson Drive's jump point are apparently random spots inside a solar system, and only go to one other system, while BT's jump points are fairly standard locations, and allow a jumpdrive equipped ship to go anywhere within it's jump range.

Some systems more then other, Tarus bears an uncanny resembles to the titular mote in god's eye.

Mechanically I can't add to what's been said.  I think the main point is, that's very slow, relative to most other science fiction that features faster than light travel (though it's dramatically faster than slower than light travel).  Since the base line average is a week from a planet to a jump point (though depending on the star it can very from a day or two to nearly a month for ultra massive stars), even traveling to a world just one jump away takes two weeks.  Any further, add in a week to recharge your jump drive, so going 60 light years (or even just 31) will take three weeks (on average).

BT is faster then TOS Trek, that's why the IS is so large.

Due to cost, complexity, and the connivance of the local Phone Company ;) HPGs aren't on every planet. There's a network of major stations (class A) on major worlds, feeding down trunks (class B & C stations). Worlds off the 'trunks' then rely on JumpShips carrying information packets to and fro.

Class C Stations are JumpShip service, as are Class D, according to Campaign Ops.

[monbvol]

Wouldn't there be some risk of ships jumping into a system colliding with (jumping into) a ship already in system? What about fleet travel?
Does anyone control this traffic?

Calling the zenith and nadir "points" is a bit of a misnomer because they are huge.

Odds of a shipping jumping into another is so low to be near zero probability.

[Vorpalstar]

Calling the zenith and nadir "points" is a bit of a misnomer because they are huge.

Odds of a shipping jumping into another is so low to be near zero probability.

Thank you for clarifying this. I was mistakenly thinking of zenith and nadir as specific points, similar to an MGRS or Lat / Long point on Earth.

[guardiandashi]

Thank you for clarifying this. I was mistakenly thinking of zenith and nadir as specific points, similar to an MGRS or Lat / Long point on Earth.

yes the zenith and nadir  jump points are really more like a cylinder projected up and down from the stars axis kind of like the artic circle on earth, but at a distance like the moon's orbit and further, and then calling that a point