MT Only: DGP Starship Operator's Manual Vol 1. Starship Operations

[snrdg082102]

Afternoon PDT,

On the TML the topic of "1G ship vs Size 8 world" suggested that a ship with an 1G MD cannot take-off from a Size 8 world.

Digging through my MT material I found "Game Rules for Starship Operations" (SOM) in DPG Starship Operator's Manual Vol. 1 pp. 59-65 is a process for taking off from the surface of a world to low orbit, high orbit, geosynch orbit, travel time from satellite to satellite orbit, world to world orbit, orbit to jump point, and jump space flight.

The "Estimating task duration in advance" section under "Key Tasks", p. 60, "Guidelines for general-purpose tasks used on other T-charts" is the one I do not have a handle on.

Inside the block is the following for "Estimating task duration in advance":

To estimate a task's duration ahead of time:
Difficult, related skill, Int (uncertain)

Referee: Use the related skill from the task being estimated. If successful, have the player roll 3D duration ahead of time to arrive at the estimated duration for the task in question. When the actual task is performed, determine the actual duration by rolling 1D - 1D and adding the result to the estimate.

If some truth, roll 1D + 1D 9thait is, 2D) and add the result to the estimate for the actual task duration.

Example:
The situation:
Predict how long to repair the maneuver drive.
The repair requires engineering skill.
The repair has a 1 hour time increment.
The Task:
To estimate the duration of the repair task:
Difficult, Engineering, Int (uncertain)

The result:
The player succeeds at the estimate task, toll 3D, and gets an estimate of 7 hours. Later, when the player does the repair, he rolls 1D followed by 1D, giving a 2 and a 4.
If the Referee got a total truth estimate: 7 + (2 - 4) = 5 hours actual duration.
If the Referee got a some truth estimate: 7 + (2 + 4) = 13 hours actual duration.

MT Referee's manual p. 13 has text referencing how uncertain risk qualifier, the SOM's instructions, and example works.

Can anyone provide a relatively easy way on how "Estimating task duration in advance" works plase?

 

[Major B]

MT0215 Referee's Companion

...
On the TML the topic of "1G ship vs Size 8 world" suggested that a ship with an 1G MD cannot take-off from a Size 8 world.
...
The "Estimating task duration in advance" section under "Key Tasks", p. 60, "Guidelines for general-purpose tasks used on other T-charts" is the one I do not have a handle on.
...

Tom, I recommend you check the Referee's Companion if you have a copy. On page 21 is a chart that provides estimated travel times (in days) for in-system travel. It is pretty comprehensive and I've used it several time to calculate how much endurance to build into a design.

I haven't read the TML topic you referenced but I think it assumes a "straight up" exit from the surface through the gravity well in which case 1G acceleration will be cancelled by the planet's gravity. Your reference from the SOM seems to be assuming an angled departure relative to the planet's surface which (I think) makes more sense. I forget the MT rules for streamlining and airfoil / wing effects off the top of my head because I have been working with T5 for some time now but in T5 an airfoil or a streamlined ship with wings gets a lift bonus allowing a 1G ship to gain orbit with relative efficiency.

Hope that helps even if I didn't exactly help with how to use the task profile to figure it out.

Mike

 

[snrdg082102]

Hello Major B,

Thank you for the reply, the info on travel times in the Referee's Companion, and a heads up about T5. I've got T5 on my to purchase wish list.

Tom, I recommend you check the Referee's Companion if you have a copy. On page 21 is a chart that provides estimated travel times (in days) for in-system travel. It is pretty comprehensive and I've used it several time to calculate how much endurance to build into a design.

I have not gotten to the point of verifying if the DPG Starship Operator's Manual Vol. I travel time for in-system matches the table in the Referee's manual. I am still trying to figure out the time from surface to orbit rules. The calculations, with rounding appear to match the Starship Operating Procedures in MT Imperial Encyclopedia pp. 92-93

I haven't read the TML topic you referenced but I think it assumes a "straight up" exit from the surface through the gravity well in which case 1G acceleration will be cancelled by the planet's gravity. Your reference from the SOM seems to be assuming an angled departure relative to the planet's surface which (I think) makes more sense. I forget the MT rules for streamlining and airfoil / wing effects off the top of my head because I have been working with T5 for some time now but in T5 an airfoil or a streamlined ship with wings gets a lift bonus allowing a 1G ship to gain orbit with relative efficiency.

The procedures in the Starship Operator's Manual does not appear to take a ship's streamlining in to consideration. It does however take in atmosphere into consideration but from what has been said the method used is backwards from reality.

Hope that helps even if I didn't exactly help with how to use the task profile to figure it out.

Mike

I am not holding my breath that someone will be along to translate the rules for me, I'm still trying to figure out the Task system as described in the Referee's Manual.

The more I dig into the Starship Operator's Manual and the procedure the more I find I'm missing the process. Thank you again for the reply.

 

[Spinward Scout]

The more I dig into the Starship Operator's Manual and the procedure the more I find I'm missing the process. Thank you again for the reply.

If I remember right, there was a flow chart at the back of the S.O.M., and I don't think it was completed before printing. I'm not sure some of the stuff in the Starship Operator's Manual worked completely well with the rest of MegaTraveller. Use what feels best for your game, but you should probably stay as close to the main GDW books as possible. Just for consistency.

Don't get me wrong, I think the S.O.M. is pretty awesome and filled with a ton of stuff.

 

[snrdg082102]

Evening PDT Spinward Scout,

If I remember right, there was a flow chart at the back of the S.O.M., and I don't think it was completed before printing. I'm not sure some of the stuff in the Starship Operator's Manual worked completely well with the rest of MegaTraveller. Use what feels best for your game, but you should probably stay as close to the main GDW books as possible. Just for consistency.

Don't get me wrong, I think the S.O.M. is pretty awesome and filled with a ton of stuff.

What I was trying to say is that I'm not figuring out what is supposed to happen in those parts that do not have an example to go by or I do not have a handle on how the task is put together even after reading through the Referee's Manual.

Thank you for the suggestions and advice.

 

[Supplement Four]

I haven't read the TML topic you referenced but I think it assumes a "straight up" exit from the surface through the gravity well in which case 1G acceleration will be cancelled by the planet's gravity.

In the early days of CT, it is alluded to that ships producing 1G thrust cannot make escape velocity from Size 8+ worlds. There is an article in an early White Dwarf Magazine that suggests that these vessels will only visit High Ports and never set down on Size 8+ worlds, transferring cargo to Zero-G orbital bins and only visiting the surface through use of surface-to-orbit taxis.

The article also suggested the use of demountable rockets that can be placed on the craft to produce escape velocity.

I like the idea, and this is how I play my CT game.

As CT matured, the idea seemed to be discarded or ignored. Aerodynamic lift is sometimes attributed to helping a ship make escape velocity when its drives are at the limit.

The SOM addresses this "problem" by stating that even a 1G M-Drive has an overdrive capability where it produces greater than 1G thrust for a very short period of time--enough time to make escape velocity from a world.

 

[David Johansen]

I've never understood why this is even a thing.

Antigravity technology makes escape velocity completely irrelevant. The only real obstacle is the atmospheric friction.

 

[Major B]

Thanks S4!

 

[Blue Ghost]

I've never understood why this is even a thing.

Antigravity technology makes escape velocity completely irrelevant. The only real obstacle is the atmospheric friction.

I always saw antigrav technology as like an energy "oil". You can put a field of "antigravity" between your ship or air raft, but it can't push you forward unless you keep cranking up the energy. Which means you would need a power plant to keep feeding your antigrav system for a higher and higher output to gain altitude. The cheap solution is to just mount a couple of thrusters and have them push your ship faster and faster so that eventually you no longer need to rely on antigravity, and can accelerate away from the gravity well.

Just me.

 

[snrdg082102]

Evening Supplement 4,

In the early days of CT, it is alluded to that ships producing 1G thrust cannot make escape velocity from Size 8+ worlds. There is an article in an early White Dwarf Magazine that suggests that these vessels will only visit High Ports and never set down on Size 8+ worlds, transferring cargo to Zero-G orbital bins and only visiting the surface through use of surface-to-orbit taxis.

The article also suggested the use of demountable rockets that can be placed on the craft to produce escape velocity.

I like the idea, and this is how I play my CT game.

As CT matured, the idea seemed to be discarded or ignored. Aerodynamic lift is sometimes attributed to helping a ship make escape velocity when its drives are at the limit.

I have the first edition of Traveller LBB1-3 and picked up the softcover FFE Classic books. The material that I have as far as I can tell made no mention of how ships landed or took-off from a world. I do recall an article about a downport that had a grid, someone suggested the article was in The Dragon. I also have a vague memory about that ships being launched with boosters from sites near the equator and using the Earth's rotation to make orbit.

The SOM addresses this "problem" by stating that even a 1G M-Drive has an overdrive capability where it produces greater than 1G thrust for a very short period of time--enough time to make escape velocity from a world.

From DGP MT SOM p. 3
"Lateral Thrust: Since the output of a drive falls to 25% when providing lateral thrust, it would seem that a 4G maneuver drive is required for a starship to hover above the ground on a planet with a 1G field. In fact, because a starship obtains full thrust directly aft, hovering id often done in a nose-up attitude."

The accompanying illustration shows a ship landing on its tail and "then gradually moving the shifting the direction of thrust so that the ship settles into a horizontal (that is lateral) landing position."

The text also mentions that ships can be "built to land and take off in an up-ended with the decks being parallel to the aft of the craft, rather than its belly."

The practice of over-driving the MD thruster plates is used to place a 1G ship into a "lateral hover at takeoff and landing."

Darn-it the topic has once again drifted off course as usual, hopefully someone will be willing to translate the example of Estimating task duration in advance into something I can understand

Also a thank-you to everyone who has replied to the topic.

 

[Supplement Four]

I have the first edition of Traveller LBB1-3 and picked up the softcover FFE Classic books. The material that I have as far as I can tell made no mention of how ships landed or took-off from a world. I do recall an article about a downport that had a grid, someone suggested the article was in The Dragon. I also have a vague memory about that ships being launched with boosters from sites near the equator and using the Earth's rotation to make orbit.

And, if you look at world surface gravity or construct some planetary templates for space combat or interplanetary travel, and its easy to start questioning how a ship that pushes 1G acceleration can make escape velocity on a world Size 9.





Whether you (universal "you") agree with the notion or not, I like using it in my CT game as it presents a lot of character to the universe. Ships with 1G drives have trouble skimming. They have to be careful not to go too deep into the GG's atmo, risking getting caught in the world's G field.

Size 8+ worlds, where TL permits, have high ports. Cargo is off-loaded in zero G. There are high G transports that transfer people from the high port to the world surface, if the PCs want to get down.

Before I started playing this way, I hardly ever saw the PCs use the ship's launch. But, now, there's a reason for it. It can make escape velocity on Size 8+ worlds.

 

[Supplement Four]

Can anyone provide a relatively easy way on how "Estimating task duration in advance" works plase?

Are you asking the MT way of rolling task time?

The time increment is 10% of the expected time it takes to do a task. If a task should take a minute to complete, then the time increment is 6 seconds.

To find actual time, roll 3D x time increment.



The GM provides the estimated time increment for the task at hand. The Uncertainty dice are used to put a variance in the 3D time roll. Normally, you roll 3D and multiply by the time increment to figure how long a task took to complete. You only do this when time is important (otherwise, don't bother with the time roll. Just estimate it and go.)

CLICK HERE: https://img.4plebs.org/boards/tg/image/1456/04/1456044099059.pdf

That will take you to a description of the UTP, where you can see how to roll Uncertainty dice (Ref rolls the same task in secret).

In this case, a character is trying to estimate the time, so the Uncertainty dice are used to vary the result.

 

[snrdg082102]

Hello PDT Supplement Four,

And, if you look at world surface gravity or construct some planetary templates for space combat or interplanetary travel, and its easy to start questioning how a ship that pushes 1G acceleration can make escape velocity on a world Size 9.


Whether you (universal "you") agree with the notion or not, I like using it in my CT game as it presents a lot of character to the universe. Ships with 1G drives have trouble skimming. They have to be careful not to go too deep into the GG's atmo, risking getting caught in the world's G field.

Size 8+ worlds, where TL permits, have high ports. Cargo is off-loaded in zero G. There are high G transports that transfer people from the high port to the world surface, if the PCs want to get down.

Before I started playing this way, I hardly ever saw the PCs use the ship's launch. But, now, there's a reason for it. It can make escape velocity on Size 8+ worlds.

I did look at the instructions on creating planetary templates and made an attempt to use the process, but not for getting into orbit from the surface. I will admit that I was not concerned with that aspect since the group I gamed with ignored the fact a 1G ship trying to leave a world with a 1G field needed more than what the MD could produce.

I like the feel you have in your game and have no problems with it, of course my Red Shirt luck would have the character fail even with a 4G ship.

Skimming for fuel at a GG is hazardous for any ship regardless of the MD G rating.

Thank you for the information and I'm really sad not living in your corner of the world. If nothing else you would have a lot of extra NPCs on hand with my bad luck.;-)

 

[snrdg082102]

Afternoon PDT Supplement Four,

Are you asking the MT way of rolling task time?

The time increment is 10% of the expected time it takes to do a task. If a task should take a minute to complete, then the time increment is 6 seconds.

To find actual time, roll 3D x time increment.



The GM provides the estimated time increment for the task at hand. The Uncertainty dice are used to put a variance in the 3D time roll. Normally, you roll 3D and multiply by the time increment to figure how long a task took to complete. You only do this when time is important (otherwise, don't bother with the time roll. Just estimate it and go.)

CLICK HERE: https://img.4plebs.org/boards/tg/image/1456/04/1456044099059.pdf

That will take you to a description of the UTP, where you can see how to roll Uncertainty dice (Ref rolls the same task in secret).

In this case, a character is trying to estimate the time, so the Uncertainty dice are used to vary the result.

I used my GDW Referee's Manual pp. 12-15 to follow DGP SOM Vol. I p. 60 Guidelines for Handling performance-based tasks. Unfortunately, I'm still not getting a handle on the rules.

Thank you for the link and the very prominent Click Here, that is the type of instruct that even this old retired submarine sailor can follow easily. I really do need all the help I can get.;-)

I get back to you once I've gone over the UTP link you provided.

 

[Supplement Four]

I really do need all the help I can get.;-)

First, what does PDT stand for?

Second, it's pretty simple.

Normally, when you want to know how long a task took, the GM will give you a time increment. The time increment is 10% of the average time it takes to complete a task.

Let's say I want to wash the exterior of the ATV. The GM says this will take, on average 90 minutes to complete. The time increment is 10% of 90 minutes, which is 9 minutes.

To find the time it actually takes me to wash the ATV, roll 3D6 and multiply by 9 minutes.

Roll 3D6 = 14. 14 * 9 = 126.

So, on average it takes 90 minutes, but it took me 126 minutes. This time.

The next time I wash the ATV, it might take longer. It might take a shorter amount of time, depending on the 3D6 roll.





Task Time Taken is not rolled on a task unless it is important to know how long the task took. Normally, you can skip this step.





With the SOM tasks that you are asking about, the task is a bit different in that the time it takes to complete the task is being predicted by the PC.

"Scotty, how long until the Jump Drive is working?"

"I dunno, Captain, maybe 24 hours."

With and Uncertain Task, the PC rolls his task normally, and the Ref rolls the same task in secret.

If both the PC and Ref roll succeed, then the result is Total Truth.

If both the PC and Ref fail, then the result is No Truth

If the PC fails and the Ref succeeds, or if the PC succeeds and the Ref fails, then the result is Some Truth.



If you get a Some Truth result, then your instruction in the SOM is to add 2D to the actual task duration.

This means, the Some Truth result indicates that the task requires 2D time increments longer to actually do than was predicted.





I never have liked the UTP method of Uncertainty. It's a long way to go, imo, for little gain. But, that's how it works.

 

[snrdg082102]

Evening Pacific Daylight Time (PDT) Supplement Four,

First, what does PDT stand for?

Second, it's pretty simple.

Normally, when you want to know how long a task took, the GM will give you a time increment. The time increment is 10% of the average time it takes to complete a task.

Let's say I want to wash the exterior of the ATV. The GM says this will take, on average 90 minutes to complete. The time increment is 10% of 90 minutes, which is 9 minutes.

To find the time it actually takes me to wash the ATV, roll 3D6 and multiply by 9 minutes.

Roll 3D6 = 14. 14 * 9 = 126.

So, on average it takes 90 minutes, but it took me 126 minutes. This time.

The next time I wash the ATV, it might take longer. It might take a shorter amount of time, depending on the 3D6 roll.





Task Time Taken is not rolled on a task unless it is important to know how long the task took. Normally, you can skip this step.





With the SOM tasks that you are asking about, the task is a bit different in that the time it takes to complete the task is being predicted by the PC.

"Scotty, how long until the Jump Drive is working?"

"I dunno, Captain, maybe 24 hours."

With and Uncertain Task, the PC rolls his task normally, and the Ref rolls the same task in secret.

If both the PC and Ref roll succeed, then the result is Total Truth.

If both the PC and Ref fail, then the result is No Truth

If the PC fails and the Ref succeeds, or if the PC succeeds and the Ref fails, then the result is Some Truth.



If you get a Some Truth result, then your instruction in the SOM is to add 2D to the actual task duration.

This means, the Some Truth result indicates that the task requires 2D time increments longer to actually do than was predicted.





I never have liked the UTP method of Uncertainty. It's a long way to go, imo, for little gain. But, that's how it works.

Thank you for the explanation which has cleared up the instruction a lot more than I've gotten on my own. I never have been involved with the actual playing of MT, so I have zero experience on UTP.

My apologies for not clearly indentifying what PDT stood for.

Again thank you for the help.

 

[estar]

In real life a rocket needs a thrust to weight ratio of greater than 1 to lift off. It then follows a curved trajectory (usually shaped to take advantage of a gravity turn) where at it apex the rocket hits orbital velocity. This irregardless of whether the planet as an atmosphere or not.

If the planet has a thick enough atmosphere and the spacecraft has aerodynamic surface then lift factors into the thrust to weight ratio. You won't need as much thrust into order to ascend into the air if you have aerodynamic surface.

To gain orbital velocity you have to shape a trajectory in such a way to minimize heating and pressure as you need to stay in the lower atmosphere for as long as possible. There will be a point where the vertical velocity with be such that it will allow you to arc above the atmosphere. At which point you can thrust until you achieved orbital velocity.

I practice this using spacecraft built using the Kerbal Space Program and Orbiter Space Simulator. When I was actively developing my Orbiter addons (http://www.ibiblio.org/mscorbit/) I got to wondering how would continuous thrust traveller-style craft would work in the simulator.


What you can't get around is when there is little to no air. You have to have a TWR greater than local gravity.

In any cases the time to reach orbital is tens of minutes. With a TWR of 1.5 you will get into orbit within 10 to 15 minutes. If overdriving is a feature it doesn't need to occur for very long in order to get into orbit.

Most real world technology have what is called a duty cycle. The one I am most familiar with is a plasma cutting torch. In addition to it rated amperage we get a duty cycle number. 100% means this can be run all day at that settings. There are plasma torches with setting that have less than 100% duty cycle. For example if it is 75% that means out of every 100 minutes only 75 can be spend cutting.

Given the prevalence of 1G or greater planets and the prevalence of 1G drives. I think it safe to assume that 1G means what the maneuver drive can do at 100% duty cycle. You could push it higher but you can't run it continuously at that level. Since the time to orbit is trivial it makes sense to me that overdrive is built in and used only for this purpose. And at the longer time scale of space combat it doesn't have any effect.

 

[snrdg082102]

Hello estar,

Thank you for the reply and additional information. With my first edition LBB1-3 I did not look at how a ship got from the ground to orbit. That was unit the TML post about a 1G drive ship not being able to lift off a Size 8 world with a 1G field. The I looked at DGP's MT Starship Operator's Manual Vol. 1 which went into the details. I vaguely recall an article, I;m not sure if it was linked to Traveller, that went into the details which involved mounting boosters and using a world's spin to help get a ship into orbit.

Again thank-you for the reply.

 

[mike wightman]

Those articloes were written by people who hadn't considered:
LBB:2 ships that operate in an atmosphere have to be 'streamlined' which implies either a lifting body hull form or even wings going by the illustrated examples.

A ship with a constant 1g thrust taxis like an aircraft, takes of like an aircraft and then climbs. As it climbs it continues to get faster due to the thinning air and constant 1g thrust. At the altitude where air can no longer provide lift the ship is already high enough that the planet's gravity is no longer 1g. It uses momentum to climb higher and now uses the difference between it's 1g and local gravity to continue accelerating to orbital velocity.

 

[kilemall]

Here's the thread we did, pretty thorough look at the topic-

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=34502