Interplanetary Travel

[sideranautae]

Dizzying, to be sure.

As for Adventure and Capital class design sequences, I may have missed the relevant tables; if you could be so kind as to mention page and paragraph?

Maneuver Drive tables in both. Can't miss them if you try and design a ship.

 

[Condottiere]

I must have, since I only note the design sequence for the Reaction Drive. In both books.

Smallcraft seems to have a design sequence for both reaction and grav drives.

 

[sideranautae]

I must have, since I only note the design sequence for the Reaction Drive. In both books.

Get new books. Yours are some of the rare ones that were missing pages

 

[Tom Kalbfus]

You only have to get to 100 diameters to use your jump drive, the gravitic thrusters is an overkill for this purpose, what you could do is reach relativistic velocities using only a fusion power plant try it some time. Lets say you took a Scout/Courier, removed the Jump Drive and devoted the jump fuel plus the space freed up by the Jump Drive for extra maneuver fuel tankage, so how long could the maneuver drive operate with all that extra power plant fuel and what's the ultimate fastest velocity it could reach? You thinking of having a STL campaign using gravitic thrusters to travel between the stars? Low Berths could come in handy right here.

You won't always be using a jump drive for interplanetary travel. Since most planets and asteroid belts are more or less fall within the systems plane of eliptic, travel from one side of the system to the other involves moving through the 100D limit of the sun. The rules state if you come within that diameter you get yoinked out of jump space. To get there safely you'd have to travel for a period to ensure your jump path did not intersect with the 100D star limit, and then when you emerged, you would have to travel in N-space for a more or less equivalent amount of time to reach your destination. With the angle you couldn't emerge within 100D of your target or else you'd probably hit the star's 100D limit.

Wait a minute, I thought the Jump Drive took a short cut through space in a higher dimension! Lets say you have a map of a solar system and you have two planets each one is beyond the 100 diameter limit but on opposite sides of the star. Now if you travel through normal space in a straight line from one planet to the other, then your path would take you within the 100-diameter limit, but if you bent or folded the map such that one planet was right on top of the other, then you could take that shortcut through the higher dimension without going past the star, that was the original explanation for the Jump Drive or a hyper drive, but I guess that's morphed into something more like a warp drive. Anyway the time spend in Jump space is either invariant or is a random factor that has nothing to do with distance crossed. I prefer the explanation that the Jump Drive is through a higher dimension and is a short cut rather than just something that allows you to go faster than the speed of light, otherwise we might as well use warp drives. Just my opinion.

Plus an interstellar ship can devote more space to cargo since it does not need additional space for a jump drive and jump fuel. The space saved would allow you to potentially double, or triple your M-drive (along with an uprated power plant), and probably still save space.

For example, a 1,000 ton freighter with an E-class M-drive/PP gives 1G acceleration. To give it Jump-1 takes 22 tons for the J-drive and 100 tons for the fuel. If you bumped the M-drive to 3G and added in the same sized powerplant you are at 50 tons total (23 tons is necessary to get 1G). So for 27 tons (which is just about the size of the J-drive) you triple your normal-space speed (and save 100MCr for the Jump-1 drive).

To put that into travel time perspective, from the Earth to Jupiter, at 1G takes 6.5 days, accelerating at 1G, then doing a turnover to arrive zero-zero at Jupiter's orbit. Which is faster than jumping. If you were going 2G it would be 4.5 days, and at 3G it would be a little less than 4 days. Bumping it all the way up to 6G's takes a total of 100 tons for the drives, 22 tons of fuel for 1 week, but would get you there in 2.5 days. So a ship travelling in N-space would be able to reach Jupiter, unload cargo, reload & refuel, and make it back to Earth before a jump-capable freighter would reach it's destination - essentially doubling the capability of the ship for roughly the same cost.

If you were hoofing it from Earth to Pluto, travel time is 8 days at 6 G's, meaning that a jump ship may or may not get there before you. Travel in N-space is underrated. Then again most games seem to be oriented around jumping from system to system, so NOT having a jump drive means either taking other people's ships, or piggybacking on a freighter to get from system to system.

But it really makes the Solar System a small place when you can go from Earth to Pluto in 8 days at 6 g. At the midpoint of your journey to Pluto your ship would be traveling at 6.912% of the speed of light, (20,736 km/sec) this is more than a single stage of a Daedalus Space Probe is capable of, it would take 63.7 years to reach alpha Centauri at this speed, since it is standard to have enough maneuver fuel to operate the drive for 2 weeks, that means a maximum velocity of 36,288 km/sec is possible which is 12.1% of the speed of light! This is serious overkill for interplanetary trips!

 

[phavoc]

Wait a minute, I thought the Jump Drive took a short cut through space in a higher dimension! Lets say you have a map of a solar system and you have two planets each one is beyond the 100 diameter limit but on opposite sides of the star. Now if you travel through normal space in a straight line from one planet to the other, then your path would take you within the 100-diameter limit, but if you bent or folded the map such that one planet was right on top of the other, then you could take that shortcut through the higher dimension without going past the star, that was the original explanation for the Jump Drive or a hyper drive, but I guess that's morphed into something more like a warp drive. Anyway the time spend in Jump space is either invariant or is a random factor that has nothing to do with distance crossed. I prefer the explanation that the Jump Drive is through a higher dimension and is a short cut rather than just something that allows you to go faster than the speed of light, otherwise we might as well use warp drives. Just my opinion.

Jump travel mechanics all the way back to CT have the 100D limit involved, which is the reason you have to carefully plot your course, and also why there are jump shadows. You can't "jump" through a large object. The gravity effect will yank you out of jump space.

But it really makes the Solar System a small place when you can go from Earth to Pluto in 8 days at 6 g. At the midpoint of your journey to Pluto your ship would be traveling at 6.912% of the speed of light, (20,736 km/sec) this is more than a single stage of a Daedalus Space Probe is capable of, it would take 63.7 years to reach alpha Centauri at this speed, since it is standard to have enough maneuver fuel to operate the drive for 2 weeks, that means a maximum velocity of 36,288 km/sec is possible which is 12.1% of the speed of light! This is serious overkill for interplanetary trips!

Fast in-system liners and shuttles will travel at higher velocities, but I suspect lowly cargo ships will bounce around at 1-2G's because the drives and upkeep are cheaper. But yeah, if you wanna reach someplace inside a system a fast M-drive is probably going to be far more cost effective than a jump-capable ship.

But, for the most part, Traveller has always focused on jumping between systems. Very little of the game has been focused on in-system travel, trade and development.

 

[Condottiere]

I must have, since I only note the design sequence for the Reaction Drive. In both books.

Get new books. Yours are some of the rare ones that were missing pages

I had a look at the page numbering sequence, and it appears that they are in tact.

Besides the fact that neither book ever claims the manoeuvre drives are grav drives, let's try a little experiment and pick a random drive and examine it.

Let's say, sX.

sX provides factor 6 acceleration for hundred ton ships.

The grav drive weighs 17 tons, the reaction drive weighs 7 tons. Or 17% and 7% respectively.

aC has only one drive type, and whatever that is, it weight 5 tons, or 5%.

Capital class quotes factor six m-drive at 3.25%.

Even if you factor in economies of scale, the percentages don't sync.

 

[Reynard]

"Besides the fact that neither book ever claims the manoeuvre drives are grav drives"

The core book keeps it simple just calling it a maneuver drive. It's the old, "Well We know what we meant.". Previous editions refer to gravitic and thruster either as the same thing or two difference engine types.

High Guard page 42, second column under DRIVES Manoeuvre Drive, "The gravitic drive is the standard for spacecraft...".

 

[Tom Kalbfus]

Wait a minute, I thought the Jump Drive took a short cut through space in a higher dimension! Lets say you have a map of a solar system and you have two planets each one is beyond the 100 diameter limit but on opposite sides of the star. Now if you travel through normal space in a straight line from one planet to the other, then your path would take you within the 100-diameter limit, but if you bent or folded the map such that one planet was right on top of the other, then you could take that shortcut through the higher dimension without going past the star, that was the original explanation for the Jump Drive or a hyper drive, but I guess that's morphed into something more like a warp drive. Anyway the time spend in Jump space is either invariant or is a random factor that has nothing to do with distance crossed. I prefer the explanation that the Jump Drive is through a higher dimension and is a short cut rather than just something that allows you to go faster than the speed of light, otherwise we might as well use warp drives. Just my opinion.

Jump travel mechanics all the way back to CT have the 100D limit involved, which is the reason you have to carefully plot your course, and also why there are jump shadows. You can't "jump" through a large object. The gravity effect will yank you out of jump space.

My point was, if a ship is in Jump Space, it is not in normal space, its path is not through normal space, so if a planet is between itself and its destination, that is irrelevant so long as the Jump is made from beyond the 100-diameter limit and it is to someplace beyond the 100 mile limit. Also what about jumping to inside a Solid Dyson Sphere. Say you have a star who's jump radius is less than the radius of a Dyson Sphere around it. There are some explorers who want to explore it, but they just can't find the entrance, they can tell that it is hollow, and they know the mass of the star inside, so they calculate a jump that will take them inside the shell of the Dyson Sphere after taking seismic measurements to determine the shell's thickness.

 

[sideranautae]

I had a look at the page numbering sequence, and it appears that they are in tact.

Besides the fact that neither book ever claims the manoeuvre drives are grav drives, let's try a little experiment and pick a random drive and examine it.

Jeez!

Okay. Look at TL descriptions MRB. Grav comes in at TL 9 for space travel.

HG. pg 41 "A ship without a functioning gravitic drive attempting re–entry without heat shielding will burn up."

Pg. 42 HG "DRIVES Manoeuvre Drive The gravitic drive is the standard for spacecraft throughout the Imperium, combining efficiency with moderately high thrust." :roll:

What kind of reactionless drives did you THINK were being spec'ed out in the drive tables????

 

[Tom Kalbfus]

Lets see, there is flubber, there is also the negative mass drive put forward by Robert Forward.
http://en.wikipedia.org/wiki/Negative_mass

 

[dragoner]

Lets see, there is flubber, there is also the negative mass drive put forward by Robert Forward.
http://en.wikipedia.org/wiki/Negative_mass

That is the effect I use for a-grav as well; negative mass emulation, "grav" being a colloquialization.

 

[sideranautae]

Lets see, there is flubber, there is also the negative mass drive put forward by Robert Forward.
http://en.wikipedia.org/wiki/Negative_mass

But, ships don't collect/purchase/carry Negative Matter. You could rewrite the rules for it though. Might be interesting.

Same problems as using anti-matter in the game. It has to be produced and have a whole expensive infrastructure built out to interstellar proportions as it doesn't occur naturally.

 

[Tom Kalbfus]

Negative matter doesn't get used up the way Antimatter does though. What you have, according to Forwards ships in his book Time Master are incredibly dense balls of negative matter, they usually have a positive or a negative charge. For instance, you could have the negative matter equivalent to a ball of protons. Since same charges normally repel, when operated on negative mass a push is a pull so elementary charges of the same clump together being repelled only by the strong nuclear force, that normally attracts. This dense ball of negative mass protons has the negative mass equal to the positive mass of the starship. Inside the ship's engine room is a negatively charged plate, electrons are dumped into the plate to attract the positively charged ball of negative matter, the ball is repelled by the opposite charge, but the charged plate is attacted to the balls opposite charge, and since its attached to the starship, it pulls the ship right along with it. or else the negative matter ball is spun to create a magnetic field and an electromagnet creates a magnetic field with the opposite polarity to the negative matter ball the electromagnet is attracted to the ball, but the ball is repelled by it. The ship and the negative matter ball accelerate in one direction and as the kinetic energy increases to the square of velocity with the ship, but the negative matter ball decreases its negative energy according to the square of its velocity as well, both cancel out with no net increase in energy. Robert Forward also had no restrictions on the use of his wormholes, they were carried around in his ships and you could walk through them into the future or the past. There was a self consistency principle at work here, that is any event observed to have happened cannot be changed by time travel, so his main character developed a strategy of not witnessing key events. He had agents witness an event such as an attempted sabotage of one of his facilities, but they didn't report on whether the attempt was successful or not, thus the character in the past made arrangements to thwart the attempt, knowing when and where it was going to happen, but not if it was successful.

http://www.publishersweekly.com/978-0-312-85214-6

 

[sideranautae]

This dense ball of negative mass protons has the negative mass equal to the positive mass of the starship. Inside the ship's engine room is a negatively charged plate, electrons are dumped into the plate to attract the positively charged ball of negative matter, the ball is repelled by the opposite charge, but the charged plate is attacted to the balls opposite charge, and since its attached to the starship, it pulls the ship right along with it.

That still violates the Laws of Motion. A created Grav well doesn't.

But, it is one of the more creative story items I've seen in a while.

 

[Tom Kalbfus]

This dense ball of negative mass protons has the negative mass equal to the positive mass of the starship. Inside the ship's engine room is a negatively charged plate, electrons are dumped into the plate to attract the positively charged ball of negative matter, the ball is repelled by the opposite charge, but the charged plate is attacted to the balls opposite charge, and since its attached to the starship, it pulls the ship right along with it.

That still violates the Laws of Motion. A created Grav well doesn't.

But, it is one of the more creative story items I've seen in a while.

Well actually gravity is just another means of throwing mass around. In order to propel a ship with gravity, the gravity field needs to reach out and pull on something or push on something if there is nothing to push or pull on, you get no propulsion.

 

[travchao999]

2. I'm told that acceleration is limited by the drive's gee factor, which means that once it hits a certain threshold, your velocity won't increase. Not being a physicist, not quite sure what to make of that.

c (speed of light) is the limit.

4.There are no grav drive design sequences for Adventure or capital class.

MRB & HG use Grav Drives as the default drives for both. You should buy both books.

MRB? What's that? I know HG is High Guard, but I don't remember an MRB.

Also, did not expect this topic to blow up like it did. I guess with grav drives, you can decelerate by artificial gravometric pull, something regular engines can't do (decelerate), and thus have to have some sort of breaking thruster like SC has.

Also, I like vector movement and combat! Attack Vector: Tactical is one of my favorite miniature games (Newtonian AeroTech too!)! But when I run my MGT game, I probably won't use the CT vector rules like I was thinking, since I don't want to overwhelm my players, as I understand not everyone can keep track of that. Of course, the other option is to have some sort of FCS that tries to FBW.

 

[sideranautae]

MRB? What's that? I know HG is High Guard, but I don't remember an MRB.

Main Rule Book

I guess with grav drives, you can decelerate by artificial gravometric pull, something regular engines can't do (decelerate), and thus have to have some sort of breaking thruster like SC has.

You just shift the grav well to being "behind" the ship.

Also, I like vector movement and combat! Attack Vector:... But when I run my MGT game, I probably won't use the CT vector rules like I was thinking, since I don't want to overwhelm my players, as I understand not everyone can keep track of that.

I taught it to MANY children over the decades. No one over age 12 should have a problem with it.

 

[travchao999]

MRB? What's that? I know HG is High Guard, but I don't remember an MRB.

Main Rule Book

I guess with grav drives, you can decelerate by artificial gravometric pull, something regular engines can't do (decelerate), and thus have to have some sort of breaking thruster like SC has.

You just shift the grav well to being "behind" the ship.

Also, I like vector movement and combat! Attack Vector:... But when I run my MGT game, I probably won't use the CT vector rules like I was thinking, since I don't want to overwhelm my players, as I understand not everyone can keep track of that.

I taught it to MANY children over the decades. No one over age 12 should have a problem with it.

You know, I thought it would be main rule book, but I've never heard it called that or would ever refer to it like that.

Anyway, thanks.

 

[Rikki Tikki Traveller]

I always thought MRB was Mongoose Rulebook!

 

[sideranautae]

I always thought MRB was Mongoose Rulebook!

Could be.