Auto-Astrogators... not that bad?

[Condottiere]

The problem with acceleration factor/zero, is that you need some hard numbers.

I'd go fractional, if there was an percentage given for that.

 

[MasterGwydion]

The problem with acceleration factor/zero, is that you need some hard numbers.

I'd go fractional, if there was an percentage given for that.

Based on space and power requirements, M-0 drives are actually M-0.25 drives.

 

[Terry Mixon]

It was mentioned in the original Traders and Gunboats:

Variants: No known variants of the xboat are actually in regular service. Two variant models have been built for experimental purposes. One model incorporated maneuver drives sufficient to produce 1-G; the loss of jump potential (reduced to jump 3) was deemed unacceptable, however, and it was not produced. The second variant included a four-ton light sail (replacing the second stateroom). This model was intended to provide emergency acceleration away from a star in the event of breakout at too close a distance. The apparent benefits from this modification were
also deemed too small for mass production. However, there are reports that some examples were produced and may be in service in the Spinward Marches.

Terry, have you considered M-Drive 0? Despite the listing talking about it only being to keep space stations in their orbit, it doesn't take much actual thrust to move a ship around usefully. Otherwise, a small reaction drive could work as an emergency measure, or to aid with recovery when the jump exit is a bit off course.

I was able to get it maneuver 1 so I didn’t need to go with maneuver 0. 0 was my initial goal and I found I could do better.

 

[Condottiere]

Based on space and power requirements, M-0 drives are actually M-0.25 drives.

Acceleration factor/zero is up in the air, as to actual thrust.

I think at the moment it depends on component:

1. Spacecraft.

2. Spacestation.

3. Detachable bridge.

4. Solar sail.

5. Possibly, manoeuvre drive after a thousand diameters.

 

[MasterGwydion]

Acceleration factor/zero is up in the air, as to actual thrust.

I think at the moment it depends on component:

1. Spacecraft.

2. Spacestation.

3. Detachable bridge.

4. Solar sail.

5. Possibly, manoeuvre drive after a thousand diameters.

M-Drive 0 is different than Acceleration 0.

One is an M-drive, the other could be any kind of drive.

 

[Condottiere]

To fit a manoeuvre or reaction drive, consult the Thrust Potential table and decide what Thrust score you want your ship to have. The figure below that Thrust score shows what percentage of the ship’s hull the manoeuvre drive consumes, in tons.

 

[MasterGwydion]

To fit a manoeuvre or reaction drive, consult the Thrust Potential table and decide what Thrust score you want your ship to have. The figure below that Thrust score shows what percentage of the ship’s hull the manoeuvre drive consumes, in tons.

I only pointed out that the M-0 drives were actually 0.25 drives. My statement makes no claim on other types of propulsion.

 

[Condottiere]

Essentially, as a concept, it's all up in the air.

Technically, factional acceleration would be between 0.51% to 0.99% volume.

On a linear scale, about half percent volume per one hundredth of a gravitational acceleration (Terran standard).

Spacestation would appear to be fixed, and non scalable.

Power requirement could be one minus a quarter, so three quarters power point divided by a hundred, per 0.01 gees, per ten tonnes of volume.

Remember, this is pure speculation.

Some of it.

 

[Terry Mixon]

I only pointed out that the M-0 drives were actually 0.25 drives. My statement makes no claim on other types of propulsion.

The book says they are good for station keeping and not much more. Not sure it will be as high as 25%.

 

[Condottiere]

I made that assumption as well.

In the beginning.

My current assumption is, unintended consequences from throwaway text.

 

[MasterGwydion]

The book says they are good for station keeping and not much more. Not sure it will be as high as 25%.

The book also says that for each point of thrust it requires 1% the volume of the ship installed on, and costs 2MCr per ton.

The chart in HG (Drive Section) says that M-0 is 0.5% and costs 2MCr per ton.

In the Space Station section, it says that a Thrust 0 M-Drive requires 0.25% of the station by volume and costs only 1MCr per ton.

So, it looks like Mongoose has no idea what an M-Drive costs per ton. 2MCr or 1MCr. It also appears that Mongoose doesn't know how to round numbers. 0.5 is rounded to 1, while 0.25 is rounded to 0. So why is something with a Thrust of 0.5 listed as Thrust 0, while Thrust 0.25 is also called Thrust 0.

So either, whatever is in Space Stations is not an M-Drive or it uses completely different rules and physics from "normal" M-drives.

 

[Sigtrygg]

2.5ms^-2 continuous thrust soon adds up...

 

[Condottiere]

 

[rinku]

One TENTH of G soon adds up. That's a metre per second per second. After an hour's thrust you're travelling at 3.6km/s (12,960km/h) and have travelled 6,480km. Turn it off and coast and you cover 311,040km a day.

I think a compact low thrust reaction drive with a few hours fuel is a very sensible option for an X-Boat. Good enough to get them on course to where the rescue ball might actually be useful. Classical X-Boats carried life support for three days after jump, so in the scenario I describe above they have close to a million km range before that runs out at 1/10th G and two hours fuel.

That seems like a pretty sensible idea.
As do M-Drives with fractional thrusts. We don't do those for simplicity, but there's no particular reason they can't exist. High Guard already mentions possible fractional thrust in regard to towing ships. But for an emergency propulsion system, reaction drives are likely a better idea anyway.

 

[Condottiere]

Never really been fleshed out.

I noticed the problem while towing.

Is there a minimum volume required for manoeuvre drives, for acceleration beyond factor/zero?

Has factor/zero actually been defined.

As regards reactionary rockets, my feeling is that it's actually one to one, in terms of volume and thrust.

 

[Terry Mixon]

Never really been fleshed out.

I noticed the problem while towing.

Is there a minimum volume required for manoeuvre drives, for acceleration beyond factor/zero?

Has factor/zero actually been defined.

As regards reactionary rockets, my feeling is that it's actually one to one, in terms of volume and thrust.

High Guard says:

A manoeuvre or reaction drive with Thrust 0 allows for an orbiting space station to maintain position but is not sufficient to move the hull any great distance.

And while that is specific for a space station, I think a maneuver/0 on a ship would have the same limitation of not moving it any great distance. That's the spirit of the rule.

 

[rinku]

CT originally just had standard hulls and standard drives, so it didn't come up. MegaTraveller and TNE worked with actual thrust and mass instead of volume and Gs, mostly. Mongoose returned to volume and whole Gs.

I think the M-0 drive would represent the minimum size for that tech, but I don't agree (or disagree) that it has to be 0.25G just because that's how it scales. What it IS is an M-Drive with too low a thrust to matter in space combat. 0.25G is probably a bit beefy for that definition - four turns of thrust can get you from some of the range bands to others. I'm more comfortable pegging it at 0.1G.

 

[Terry Mixon]

CT originally just had standard hulls and standard drives, so it didn't come up. MegaTraveller and TNE worked with actual thrust and mass instead of volume and Gs, mostly. Mongoose returned to volume and whole Gs.

I think the M-0 drive would represent the minimum size for that tech, but I don't agree (or disagree) that it has to be 0.25G just because that's how it scales. What it IS is an M-Drive with too low a thrust to matter in space combat. 0.25G is probably a bit beefy for that definition - four turns of thrust can get you from some of the range bands to others. I'm more comfortable pegging it at 0.1G.

Or peg it at .01 or even .001. Something miniscule. It's supposed to not be able to move the ship/station any great distance, so really small numbers would be better.

 

[Condottiere]

Remember, you can make a soft planetary landing, with factor/zero.

And, of course, get there in the first place.

 

[rinku]

High Guard says:



And while that is specific for a space station, I think a maneuver/0 on a ship would have the same limitation of not moving it any great distance. That's the spirit of the rule.

Right. Despite the precedent of Thrust-0 solar sails and M-0 detachable bridges, that clearly DO travel. I take that rule to apply to stations and other massive vessels, but we can disagree on that.

But in the case of reaction drives at least (which are not made up pseudoscience tech) it makes sense that you could design one for a specific fractional thrust. Step aside from Thrust-0 and go straight to Thrust-0.1.