The Star Frontiers "Jump Drive"

[Space Cadet]

I was looking over the Star Frontiers rules, and according to that, all a ship needed to do is reach 1% of the speed of light and it entered the "void" a timeless region of space where FTL was possible, this led to the idea of a "Star Frontiers" Jump Drive, instead of having to travel 100 diameters from a planet to activate the jump drive, the starship has to accelerate to 1% of the speed of light or 2,997.9 km/sec relative to the star its departing from and in the intended direction of travel. The actual Jump would be instantaneous, the ship would travel 1 parsec away in the direction it was traveling it while maintaining the same velocity. A jump-2 drive wopuild travel 2 parsecs with the same requirements, a jump-3 drive would go three parsecs etc. The duration in jump space would be instantaneous. All the ships crew would know is that at one moment they are at one location and in the next at another. The Ship would still have to slow down to match the target star's velocity. The jump fuel requirements of the jump drive would be neglegible although the more capable jump drives would be more massive than the less capable ones. How would this affect the Traveller setting do you think as opposed to using the 100 diameter requirement. I've calculated that it takes 3.5 days to reach 1% of the speed of light while under 1 g acceleration.

 

[redwalker]

While travel might be faster, the crucial thing is that ships without jump drive fuel requirements would be able to use huge volumes of hull space for other things.

A battleship that has 50% of its volume devoted to fuel in standard Traveller might have only 5% of its volume devoted to fuel with your rule variant.

That space would probably be filled with marines, rockets, fighters, etc.

 

[flykiller]

it would eliminate the 1 week jump communication aspect of traveller. an M6 ship could leave one world and arrive at the next in 28 hours - be a lot like star wars.

all warships would be J6-capable - assuming J6 is even a limit anymore. naval operations would be must faster, almost on par with modern ground op responsiveness. logistics requirements would disappear except for the most long-ranged ops. a ship could perform J6 after J6 after J6 with minimum regard for refueling. strategic naval "front lines", already ephemeral because of jump, would completely disappear. a world like regina could be hit by a major zhodani naval task force with absolutely no warning whatsoever.

merchant ships could easily afford to be M6/J6-capable as well, since they could pull 120 jumps per year instead of just 32. passenger travel would no longer be a matter of spending a week in a stateroom, but a day in a bunkroom. travel by the masses would be feasible

much more regulation from Capital, since a round-trip journey would now take only two months. lots more regulations, bureaucracy, imperial contact. far less need for any nobility.

much more future shock. so much more news so much more rapidly.

 

[Space Cadet]

One thing I haven't considered, making multiple jumps makes the difference between a J1 and a J6 meaningless if you can jump as many times as you want within seconds of each other since each jump is instantaneous. There are a few considerations.

Mid course correction: the ship not only has to be travelling at 1% of the speed of light, it has to be traveling at 1% of the speed of light in the direction of the destination. The further the distance to the destination, the more jumps that will be required and the more mid course corrections that will be required.

After each jump the ship will have to take some sensor measurements, determine where it is, its direction of travel, and the direction of travel it must have to further close on the destination.
The path the ship takes through the void is the same as the path it would take had the ship traveled the entire distance through normal space at 1% of the speed of light, gravity will effect its path, and consequently the direction of travel may be a little off from what it was upon going into jump., the ship will have to maneuver and perform a mid course correction.

Also the jump drives capacitors will have to be recharged. The capacitors need to accumulate sufficient energy to allow the ship to enter the void. also the higher jump numbered drives should be more energy efficient.

Lets say a J1 drive requires 1 unit of energy accumulated after a week acceleration at 1-g to jump 1 parsec.

The J2 Drive would require 1.5 units of energy to jump 2 parsecs after a week of acceleration at 1-g

Two successive J1 jumps would require 2 energy units, which if used in a J3 drive would allow for a 3 parsec jump.

 

[LordVince]

Remember that with LightSpeed, you're dealing with Relativistics. Now, I'll be the first to admith that the Relativistic Time Dialation at 1% of LightSpeed may be minute -- but it's still there.

Take this a small step further -- once you hit the 1% lightSpeed Limit, you can engage this Jump Drive and !poof! you're at your destination. Well, it may be a !poof! to YOU, aboard the ship, but who says it's !poof! to the rest of the 'Verse?

By your calculations, it'll take 3.5 days to reach 1% LightSpeed at 1G -- the classic "week" -- but it would take significantly less than that at higher G accelleration; thus a ship with M6/J6 would take LESS time to travel 6 Parsecs than an M1/J1 would take to cross just 1 Parsec.

Unless that !poof! was a compressed Relativistic Time Dialation. The Crew experiences "No Time" during the "Jump", but the rest of the 'Verse still experiences the "week" of transit time.

Now, obviously this method would still give an advantage to the higher-G ships -- they can still hit the 1% LightSpeed Limit faster -- but they could do that ANYway, right? The only real advantage to this is just that you don't have to "spend time" in jumpspace -- and I've gamed with a few "Short Attention-Span Gamers" in my time, with whom this system would be quite appealing.

I mean, be honest, unless you're gonna inflict some mechanical difficulty or stowaway or hijack scenario on your Gamers, how often do we, as GM's, just say "the week in Jumpspace passes uneventfully"? huh? C'mon, admit it! ^_^

 

[Space Cadet]

Originally posted by Lord Vince:
Remember that with LightSpeed, you're dealing with Relativistics. Now, I'll be the first to admith that the Relativistic Time Dialation at 1% of LightSpeed may be minute -- but it's still there.

Take this a small step further -- once you hit the 1% lightSpeed Limit, you can engage this Jump Drive and !poof! you're at your destination. Well, it may be a !poof! to YOU, aboard the ship, but who says it's !poof! to the rest of the 'Verse?

By your calculations, it'll take 3.5 days to reach 1% LightSpeed at 1G -- the classic "week" -- but it would take significantly less than that at higher G accelleration; thus a ship with M6/J6 would take LESS time to travel 6 Parsecs than an M1/J1 would take to cross just 1 Parsec.

You are assuming that there is some sort of onboard artificial gravity control, but what if there wasn't? What if accelerating at 6-G meant being strapped to an acceleration couch the entire time? Would you want to be strapped to an acceleration couch for 28 hours at 6-Gs, unable to move, unable to go to the bathroom or even eat your meals normally. You just have to sit in that acceleration couch for 14 hours, then get a break while you go into jump and then sit in the acceleration couch for another 14 hours. Wouldn't be much fun would it.

If you accelerate at 1-G for 3.5 days, you can build your decks taking this acceleration into account Forward would be up, and the Stern would be down.

Originally posted by Lord Vince:
[QB]Unless that !poof! was a compressed Relativistic Time Dialation. The Crew experiences "No Time" during the "Jump", but the rest of the 'Verse still experiences the "week" of transit time.

Now, obviously this method would still give an advantage to the higher-G ships -- they can still hit the 1% LightSpeed Limit faster -- but they could do that ANYway, right? The only real advantage to this is just that you don't have to "spend time" in jumpspace -- and I've gamed with a few "Short Attention-Span Gamers" in my time, with whom this system would be quite appealing.

I don't think it can or should be used as a stutterwarp, were you go Poof Poof Poof. I think there is the charging of capacitors in volved and building up of potential. Once you hit Jump, you've released all that energy, and you have to build it up again for the next jump. The power plant can create this energy on the fly, the energy must be channeled into an accumulator and then released into the jump drive when the jump button is pushed. How long this takes, lets say it takes a day to fully charge the capacitors for another jump, by channeling the energy over this time into the jump drive. The power plant certainly can't generate this energy all at once, so it must generate it over time.

Lets say the power output of the plant in part determines how quickly the jump drive accumulators can aquire sufficient energy to make a jump. Lets also say the power cables can only carry so much current before they short out or melt. So lets say a minimum of 12 hours, but the average power plant takes a day to do this, it is certainly better if you have a Jump-2 drive that can jump 2 parsecs all at once rather than Jump-1 then wait a day and jump-1 again.

Originally posted by Lord Vince:
I mean, be honest, unless you're gonna inflict some mechanical difficulty or stowaway or hijack scenario on your Gamers, how often do we, as GM's, just say "the week in Jumpspace passes uneventfully"? huh? C'mon, admit it! ^_^

 

[Space Cadet]

How about this:

Jump Drives
Type TL Cost Size EP
Jump-1 09 MCr4 1 ton 14,400
Jump-2 11 MCr6 1.5 tons 28,800
Jump-3 12 MCr8 2 tons 43,200
Jump-4 13 MCr10 2.5 tons 57,600
Jump-5 14 MCr12 3 tons 72,000
Jump-6 15 MCr14 3.5 tons 86,400

Assume power plants generate their EP rating every combat round, that is 6 seconds, there are 14,400 combat rounds in a day. So each combat round add the EP rating for every combat round that elapses, and it all accumulates in the Jump Drives accumulator until the Jump Drive is activated. Then the total EP accumulated in the drive goes down to zero. The Jump Drive accumulators can stay fully charged indefinitely, and it typically builds up charge whenever the power plant is on and their are spare EPs that aren't being utilized.

 

[Space Cadet]

Originally posted by Lord Vince:
Remember that with LightSpeed, you're dealing with Relativistics. Now, I'll be the first to admith that the Relativistic Time Dialation at 1% of LightSpeed may be minute -- but it's still there.

Take this a small step further -- once you hit the 1% lightSpeed Limit, you can engage this Jump Drive and !poof! you're at your destination. Well, it may be a !poof! to YOU, aboard the ship, but who says it's !poof! to the rest of the 'Verse?

By your calculations, it'll take 3.5 days to reach 1% LightSpeed at 1G -- the classic "week" -- but it would take significantly less than that at higher G accelleration; thus a ship with M6/J6 would take LESS time to travel 6 Parsecs than an M1/J1 would take to cross just 1 Parsec.

Unless that !poof! was a compressed Relativistic Time Dialation. The Crew experiences "No Time" during the "Jump", but the rest of the 'Verse still experiences the "week" of transit time.

There is no real significant time dialation at 1% of the speed of light. For most practical purposes, you can ignore time dialation and simply divide 2,997,924 meters per second by your acceleration in Gs multiplied by 9.8, to get how many seconds it takes to reach that velocity.

Originally posted by Lord Vince:
Now, obviously this method would still give an advantage to the higher-G ships -- they can still hit the 1% LightSpeed Limit faster -- but they could do that ANYway, right? The only real advantage to this is just that you don't have to "spend time" in jumpspace -- and I've gamed with a few "Short Attention-Span Gamers" in my time, with whom this system would be quite appealing.

Another advantage is that incoming ships can be detected from a long way off rather than suddenly appearing at the 100 diameter limit, this gives the planetary defenses more time to react if there is long range radar to detect ships entering the Star System. Ships will have to come out of jump a ways off to give them space to decelerate and match velocities with the planet. The Jump Drives aren't precise enough to place ships in the vicintity of planets such as they are on a collision course at 1% of the speed of light. Most likely what would happen if this were attemped is the ship would emerge within the system and rapidly leave the system at 1% of the speed of light, the ship would then have to kill its forward velocity, taking 3.5 days, and take another 7 days to accelerate and decellerate so that its back in the vicinity of the planet that it originally intended to approach.

Originally posted by Lord Vince:
I mean, be honest, unless you're gonna inflict some mechanical difficulty or stowaway or hijack scenario on your Gamers, how often do we, as GM's, just say "the week in Jumpspace passes uneventfully"? huh? C'mon, admit it! ^_^

The Ship's actually spend no time in Jump Space, the trip from entering Jump space to where it leaves jump space is instantaneous, the ship basically teleports, this gives it plenty of time to be intercepted by pirates or planetary defense forces on the way to the planet. Travel is not quite as uneventful as just passing the time in Jump Space where nothing can touch your ship.