Escape Velocity

[Supplement Four]

Originally posted by far-trader:
And if they did it simply wasn't factored as a neccessary complication.

Yep. That's it. I'd bet on it.

I think they did think about it. I just think it wasn't harped on because it wasn't, as you say, a "neccessary complication".

I just got through reading an interview with MWM (old interview from the late 70's or early 80's), and the interviewer brought up Traveller's lean towards realism...and the fact that a 2D space map is used instead of a 3D system.

Marc said that they definitely worked on a 3D system, and had some ideas on how to implement it, but in the end, they just decided that the 2D map was easier. So...Traveller has 2D hex maps for space.

That's gotta be what happened to this escape velocity thing.

Does anybody have a 1st edition Traveller set? I wonder if it was stated in that version and then omitted (along with the funky damage rolls of 3D -3 and the like) when the second edition was printed.

Anyway, I was just offering alternatives to rebuilding the entire game from the ground up (ooh, punny

) which is what you'd pretty much have to do if you start factoring gravity into every trip. Because you can't just look at the Gs a starship has, you have to figure out it's mass as well. Loaded and unloaded, and everything inbetween, every time the players approach a planet. Too much work, far easier to use the contra-grav field and ignore mass and gravity.

Actually, I disagree. I am going to start using it in my game (and trust me, I like "simple"), and all that really needs to happen is to look at the world's Size code.

If you're on a 1G ship, you can land on a Size 7 world or less. On Size 8+ worlds, you'll have to make orbit, dock at the high port, use a shuttle service or your launch (or maybe even use the White Dwarf boosters...which I don't think I'll allow in my game).

But, it's a simple mechanic, really. If you're in a 2G ship or better, you really don't have to worry about it. It's only an issue for 1G vessels.

And, with 1G vessels, just look at the UPP Size code. 7-, you can land. 8+, you can't.

Simple.

 

[Supplement Four]

Originally posted by far-trader:
And if they did it simply wasn't factored as a neccessary complication.

Yep. That's it. I'd bet on it.

I think they did think about it. I just think it wasn't harped on because it wasn't, as you say, a "neccessary complication".

I just got through reading an interview with MWM (old interview from the late 70's or early 80's), and the interviewer brought up Traveller's lean towards realism...and the fact that a 2D space map is used instead of a 3D system.

Marc said that they definitely worked on a 3D system, and had some ideas on how to implement it, but in the end, they just decided that the 2D map was easier. So...Traveller has 2D hex maps for space.

That's gotta be what happened to this escape velocity thing.

Does anybody have a 1st edition Traveller set? I wonder if it was stated in that version and then omitted (along with the funky damage rolls of 3D -3 and the like) when the second edition was printed.

Anyway, I was just offering alternatives to rebuilding the entire game from the ground up (ooh, punny

) which is what you'd pretty much have to do if you start factoring gravity into every trip. Because you can't just look at the Gs a starship has, you have to figure out it's mass as well. Loaded and unloaded, and everything inbetween, every time the players approach a planet. Too much work, far easier to use the contra-grav field and ignore mass and gravity.

Actually, I disagree. I am going to start using it in my game (and trust me, I like "simple"), and all that really needs to happen is to look at the world's Size code.

If you're on a 1G ship, you can land on a Size 7 world or less. On Size 8+ worlds, you'll have to make orbit, dock at the high port, use a shuttle service or your launch (or maybe even use the White Dwarf boosters...which I don't think I'll allow in my game).

But, it's a simple mechanic, really. If you're in a 2G ship or better, you really don't have to worry about it. It's only an issue for 1G vessels.

And, with 1G vessels, just look at the UPP Size code. 7-, you can land. 8+, you can't.

Simple.

 

[Supplement Four]

Originally posted by Maladominus:

I already quoted Loren verbatim. What part of "and a maneuver drive rated for 2Gs" did you not understand? (just kidding)

What I didn't understand was: Did the ship's stats show a 1G M-Drive, but the text said it was "rated for 2G" for the atmo flights.

Or, did the stats for the vessel say 2G.

since I see in your pic, it's the later...which makes that launch different from the 1G launch in the Traveller Book.

Yes, this is the obvious conclusion. And given earlier in this discussion, Veltyen clearly demonstrated from past CT/MT documentation that a non-airframe vessel would be *limited* to a subsonic speed of 1000kph, Loren seems to follow that assessment exactly.

That type of thing is in Striker as well, but it's under "aircraft", which is handled separately from grav vehicles...I think, I just skimmed it.

But, yes, there are max speeds due to various airframes, and there are drag penalties for things like turrets that stick out of the craft.

Striker. Book 3. Pg. 26.

I posted partial-screenshot for illustration purposes only, so I'm hoping this is in Fair Use. I'll remove it soon, as my point hits home.

Nobody's going to jump on you for posting that little bit of text.

-S4

 

[Supplement Four]

Originally posted by Maladominus:

I already quoted Loren verbatim. What part of "and a maneuver drive rated for 2Gs" did you not understand? (just kidding)

What I didn't understand was: Did the ship's stats show a 1G M-Drive, but the text said it was "rated for 2G" for the atmo flights.

Or, did the stats for the vessel say 2G.

since I see in your pic, it's the later...which makes that launch different from the 1G launch in the Traveller Book.

Yes, this is the obvious conclusion. And given earlier in this discussion, Veltyen clearly demonstrated from past CT/MT documentation that a non-airframe vessel would be *limited* to a subsonic speed of 1000kph, Loren seems to follow that assessment exactly.

That type of thing is in Striker as well, but it's under "aircraft", which is handled separately from grav vehicles...I think, I just skimmed it.

But, yes, there are max speeds due to various airframes, and there are drag penalties for things like turrets that stick out of the craft.

Striker. Book 3. Pg. 26.

I posted partial-screenshot for illustration purposes only, so I'm hoping this is in Fair Use. I'll remove it soon, as my point hits home.

Nobody's going to jump on you for posting that little bit of text.

-S4

 

[Supplement Four]

Good Gawd, I hate that.

I just wrote this detailed post about how I was going to start using this rule in my game and why.

I covered everything: How to quickly see if your 1G ship could land on a world; Why I chose to do it; What I thought it brought to the game; Examples; Neat stuff...

And I hit "Add Reply"...

..and I am taken to a page that says: SERVER BUSY.

I have no choice but to hit the BACK button.

And there, in the little white reply box, I see that all my well-thought-out words supporting my choice to use this system are GONE.

GONE. GONE. GONE.

Crap.

I'm not writing it again.

Oh well.

-S4

 

[Supplement Four]

Good Gawd, I hate that.

I just wrote this detailed post about how I was going to start using this rule in my game and why.

I covered everything: How to quickly see if your 1G ship could land on a world; Why I chose to do it; What I thought it brought to the game; Examples; Neat stuff...

And I hit "Add Reply"...

..and I am taken to a page that says: SERVER BUSY.

I have no choice but to hit the BACK button.

And there, in the little white reply box, I see that all my well-thought-out words supporting my choice to use this system are GONE.

GONE. GONE. GONE.

Crap.

I'm not writing it again.

Oh well.

-S4

 

[far-trader]

Bummer

 

[far-trader]

Bummer

 

[Supplement Four]

Originally posted by far-trader:
Bummer

Yessir. Bummer. I think I would have enjoyed your response given your position on the other side of the continuum of this issue.

But, I have thought of a new wrinkle. Skimming at a Gas Giant.

Some GGs have some pretty steep gravity wells. THAT means that a 1G starship captain might not have skimming as an option. He'll need less dense GGs like Uranus (surface gravity of 0.887).

It ain't gonna be easy being a cap'n of a 1G free trader in my campaign. Lots of issues to deal with.

Of course, a ship won't go to the surface of a GG to skim. Just the upper atmosphere. Which means we're talking .75 of the GG's G rating.

This means that a ship, with a 1G M-Drive, could skim just about any but the biggest GGs. Saturn. Uranus. Neptune. All below 1G in the upper atmo.

Jupiter is off limits, though.

For easy figurin', it'd be Small GG's that 1G starships can skim (less than 60,000 km radius). Large GG's (60,000 km radius or larger) would be off limits for a 1G vessel.

GG info sometimes comes with published UPP data. I know my Spinward Marches sector data shows number of GG's in a system. I typically use Heaven & Earth to quickly detail a system I know my players are going to as well. I have it printed out--in case I need something during the game.

But, in a pinch (as in the players go somewhere unexpected), it's simple to roll on the table on pg. 28 of Book 6. That'll tell you real quick how many GGs there are in the system and if they're large or small GGs. It just takes a 2D roll for GG presence. A 2D roll for number of GGs, if one is present. And a 1D roll per GG for size. Bam, bam, you've got all the info you need if you need to go skimming fuel in your 1G starship all of a sudden.

-S4

 

[Supplement Four]

Originally posted by far-trader:
Bummer

Yessir. Bummer. I think I would have enjoyed your response given your position on the other side of the continuum of this issue.

But, I have thought of a new wrinkle. Skimming at a Gas Giant.

Some GGs have some pretty steep gravity wells. THAT means that a 1G starship captain might not have skimming as an option. He'll need less dense GGs like Uranus (surface gravity of 0.887).

It ain't gonna be easy being a cap'n of a 1G free trader in my campaign. Lots of issues to deal with.

Of course, a ship won't go to the surface of a GG to skim. Just the upper atmosphere. Which means we're talking .75 of the GG's G rating.

This means that a ship, with a 1G M-Drive, could skim just about any but the biggest GGs. Saturn. Uranus. Neptune. All below 1G in the upper atmo.

Jupiter is off limits, though.

For easy figurin', it'd be Small GG's that 1G starships can skim (less than 60,000 km radius). Large GG's (60,000 km radius or larger) would be off limits for a 1G vessel.

GG info sometimes comes with published UPP data. I know my Spinward Marches sector data shows number of GG's in a system. I typically use Heaven & Earth to quickly detail a system I know my players are going to as well. I have it printed out--in case I need something during the game.

But, in a pinch (as in the players go somewhere unexpected), it's simple to roll on the table on pg. 28 of Book 6. That'll tell you real quick how many GGs there are in the system and if they're large or small GGs. It just takes a 2D roll for GG presence. A 2D roll for number of GGs, if one is present. And a 1D roll per GG for size. Bam, bam, you've got all the info you need if you need to go skimming fuel in your 1G starship all of a sudden.

-S4

 

[Supplement Four]

Can your 1G starship land?

If you're using this old Traveller idea, like I am going to do in my game, then the answer to that question is simple:

1G Starships can land on worlds of Size 7 or smaller.

That can't land on worlds Size 8+.





Other quicky rules:

The planet's size code from its UPP is typically all you need. Size 8+? Can't land. Can't make escape velocity to leave the planet.

If you need to get more detailed for some reason, just pop open Book 2 to pg. 37. There, on the table, you'll see surface gravity for all sizes of worlds in Gs.

For example, if your 1G starship traveled to a Size 6 world, it's thrust would be reduced to just over half a G.

1 - 0.422 = 0.578

That should be all you need if you need to figure something using the travel formula.




But...let's say you really want to know the vessel's atmospheric speed on that world. Simple. Just pop open Striker Book 3 to pg. 11...which will refer you to a table on pg. 5 of the Striker Design Sequences.

See the table? Just pick the closest G rating to your ship. Your max speed is cross referenced on that table.

We see our ship above is doing 0.578 Gs. That's close to .6 Gs, so our ship will have a max speed of 720 khp and a cruise speed of 540 kph.




Still want to get more detailed? You don't need to, but if you want to, all you have to do is interpolate the table.

720 - 600 = 120

120 / 10 = 12

12 x 7 = 84

600 + 84 = 684.

Your Max Speed on a Size 6 world is 684 kph, and your cruise speed is 513 (.75 of max).

You probably will never have to go beyond what I say above...that a 1G vessel can land on Size 7- worlds, and just leave it at that.

But, if you want to get more detailed, the info in Book 2 and Striker will allow you to make some quickie calculations in 1-3 minutes.




But...what if the 1G vessel is at a main world of Size 8+?

Well, Class A starports will also have high ports. Class B starports will probably a highport. The ship can dock there. Class C+ starports will have shuttle service to orbit, and there's probably a mess of other 1G vessels transferring cargo to shuttles in orbit for transport dirtside.

This is all up to the GM.

If we're talking a Class D or E starport, there'll only be a small chance of shuttle service. With a Class X starport, the 1G vessel is S. O. L. It'll need some ship's vehicle to reach the surface (which a good captain of a 1G vessel would have thought of before leaving port).

Also, you can use the WD booster idea, at the head of this thread. I don't think I'm going to use them in my campaign, though.

 

[Supplement Four]

Can your 1G starship land?

If you're using this old Traveller idea, like I am going to do in my game, then the answer to that question is simple:

1G Starships can land on worlds of Size 7 or smaller.

That can't land on worlds Size 8+.





Other quicky rules:

The planet's size code from its UPP is typically all you need. Size 8+? Can't land. Can't make escape velocity to leave the planet.

If you need to get more detailed for some reason, just pop open Book 2 to pg. 37. There, on the table, you'll see surface gravity for all sizes of worlds in Gs.

For example, if your 1G starship traveled to a Size 6 world, it's thrust would be reduced to just over half a G.

1 - 0.422 = 0.578

That should be all you need if you need to figure something using the travel formula.




But...let's say you really want to know the vessel's atmospheric speed on that world. Simple. Just pop open Striker Book 3 to pg. 11...which will refer you to a table on pg. 5 of the Striker Design Sequences.

See the table? Just pick the closest G rating to your ship. Your max speed is cross referenced on that table.

We see our ship above is doing 0.578 Gs. That's close to .6 Gs, so our ship will have a max speed of 720 khp and a cruise speed of 540 kph.




Still want to get more detailed? You don't need to, but if you want to, all you have to do is interpolate the table.

720 - 600 = 120

120 / 10 = 12

12 x 7 = 84

600 + 84 = 684.

Your Max Speed on a Size 6 world is 684 kph, and your cruise speed is 513 (.75 of max).

You probably will never have to go beyond what I say above...that a 1G vessel can land on Size 7- worlds, and just leave it at that.

But, if you want to get more detailed, the info in Book 2 and Striker will allow you to make some quickie calculations in 1-3 minutes.




But...what if the 1G vessel is at a main world of Size 8+?

Well, Class A starports will also have high ports. Class B starports will probably a highport. The ship can dock there. Class C+ starports will have shuttle service to orbit, and there's probably a mess of other 1G vessels transferring cargo to shuttles in orbit for transport dirtside.

This is all up to the GM.

If we're talking a Class D or E starport, there'll only be a small chance of shuttle service. With a Class X starport, the 1G vessel is S. O. L. It'll need some ship's vehicle to reach the surface (which a good captain of a 1G vessel would have thought of before leaving port).

Also, you can use the WD booster idea, at the head of this thread. I don't think I'm going to use them in my campaign, though.

 

[far-trader]

Originally posted by Supplement Four:
</font><blockquote>quote:</font><hr />Originally posted by far-trader:
Bummer

Yessir. Bummer. I think I would have enjoyed your response given your position on the other side of the continuum of this issue. </font>[/QUOTE]

No less than I would have enjoyed your take on it. Ah, is that it above? I'll have to have a look later.

Originally posted by Supplement Four:
But, I have thought of a new wrinkle. Skimming at a Gas Giant....

Many good ideas there. I'd add that one could attempt a GG skimming run with less than the required Gs at increased risk. You'd be making a dive instead of a loiter. Going deeper for a quicker fill and using the built up speed to reach escape velocity.

I figure GG skimming is not recommended in general and outright against the charter of most merchant insurers. So if you're making payments on a commercial ship and skim a GG for fuel you could find your licence suspended while they investigate and possibly lose your ship.

If you survive the attempt...

I also figure the reason it's not done is because it's hazardous. Doubly so if you're not an expert pilot with a sturdy ship and extra Gs in case.

Besides the possible foul weather, there's electrical storms, radiation, and as you mentioned gravity. It's not someplace you want to take a old Free-Trader with a spotty maintenance record.

The Navy on the other hand treats it as a fairly routine operation. Their ships are built to do it and their pilots are trained for it.

 

[far-trader]

Originally posted by Supplement Four:
</font><blockquote>quote:</font><hr />Originally posted by far-trader:
Bummer

Yessir. Bummer. I think I would have enjoyed your response given your position on the other side of the continuum of this issue. </font>[/QUOTE]

No less than I would have enjoyed your take on it. Ah, is that it above? I'll have to have a look later.

Originally posted by Supplement Four:
But, I have thought of a new wrinkle. Skimming at a Gas Giant....

Many good ideas there. I'd add that one could attempt a GG skimming run with less than the required Gs at increased risk. You'd be making a dive instead of a loiter. Going deeper for a quicker fill and using the built up speed to reach escape velocity.

I figure GG skimming is not recommended in general and outright against the charter of most merchant insurers. So if you're making payments on a commercial ship and skim a GG for fuel you could find your licence suspended while they investigate and possibly lose your ship.

If you survive the attempt...

I also figure the reason it's not done is because it's hazardous. Doubly so if you're not an expert pilot with a sturdy ship and extra Gs in case.

Besides the possible foul weather, there's electrical storms, radiation, and as you mentioned gravity. It's not someplace you want to take a old Free-Trader with a spotty maintenance record.

The Navy on the other hand treats it as a fairly routine operation. Their ships are built to do it and their pilots are trained for it.

 

[Supplement Four]

Originally posted by far-trader:
Ah, is that it above? I'll have to have a look later.

Naw...not what I wrote that got itself ate by the BUSY FRAKIN' SERVER.

I just jotted down some notes for easy play for anyone wanted to incorporate the 1G-escape-velocity-thing in their games.

On the surface, I think some might think it hard work. I was trying to show them that it really isn't.

I figure GG skimming is not recommended in general and outright against the charter of most merchant insurers.

Here, we're on the same side of the continuum. I completely agree.

So, here's a question...

The Traveller rules seem to make GG skimming easy but time consuming (8 hours).

How would you handle the danger in a game?

What's the risk?

Implement damage to the ship if a pilot roll is bricked?

Too many CT players look at GG skimming as a way to sqeeze some profit out of a cargo run.

In fact, some ships, like the Type A2 Far Trader, with it's extremely thin margins vs. operating cost, almost have to skim in order to make a profit.

So, how would a GM reconcile all this?

 

[Supplement Four]

Originally posted by far-trader:
Ah, is that it above? I'll have to have a look later.

Naw...not what I wrote that got itself ate by the BUSY FRAKIN' SERVER.

I just jotted down some notes for easy play for anyone wanted to incorporate the 1G-escape-velocity-thing in their games.

On the surface, I think some might think it hard work. I was trying to show them that it really isn't.

I figure GG skimming is not recommended in general and outright against the charter of most merchant insurers.

Here, we're on the same side of the continuum. I completely agree.

So, here's a question...

The Traveller rules seem to make GG skimming easy but time consuming (8 hours).

How would you handle the danger in a game?

What's the risk?

Implement damage to the ship if a pilot roll is bricked?

Too many CT players look at GG skimming as a way to sqeeze some profit out of a cargo run.

In fact, some ships, like the Type A2 Far Trader, with it's extremely thin margins vs. operating cost, almost have to skim in order to make a profit.

So, how would a GM reconcile all this?

 

[Maladominus]

Originally posted by Supplement Four:

The Traveller rules seem to make GG skimming easy but time consuming (8 hours).

How would you handle the danger in a game?

What's the risk?

Each time they skim the GG atmosphere, have a *small* chance to Encounter a Gas Giant Cloud Storm. You know? Like that HUGE Godzilla sized gas storm eyeball on the surface of Jupiter? Yeah, a swirling cloudstorm about the size of a gigantic continent. It would be like a mega-cyclone even at the upper atmospheres. Should the storm suddenly move in the direction of the Starship refueling in the upper atmosphere.... UH OH! Your Piloting skill better be very good... altho an alert/skillfull Navigator should detect it in a timely manner before it could pose a danger to the ship.

Quoted from the Hubble Website:

When 17th-century astronomers first turned their telescopes to Jupiter, they noted a conspicuous reddish spot on the giant planet. This Great Red Spot is still present in Jupiter's atmosphere, more than 300 years later. It is now known that it is a vast storm, spinning like a cyclone. Unlike a low-pressure hurricane in the Caribbean Sea, however, the Red Spot rotates in a counterclockwise direction in the Southern Hemisphere, showing that it is a high-pressure system. Winds inside this Jovian storm reach speeds of about 270 mph.

The Red Spot is the largest known storm in the solar system. With a diameter of 15,400 miles, it is almost twice the size of the entire Earth and one-sixth the diameter of Jupiter itself.

 

[Maladominus]

Originally posted by Supplement Four:

The Traveller rules seem to make GG skimming easy but time consuming (8 hours).

How would you handle the danger in a game?

What's the risk?

Each time they skim the GG atmosphere, have a *small* chance to Encounter a Gas Giant Cloud Storm. You know? Like that HUGE Godzilla sized gas storm eyeball on the surface of Jupiter? Yeah, a swirling cloudstorm about the size of a gigantic continent. It would be like a mega-cyclone even at the upper atmospheres. Should the storm suddenly move in the direction of the Starship refueling in the upper atmosphere.... UH OH! Your Piloting skill better be very good... altho an alert/skillfull Navigator should detect it in a timely manner before it could pose a danger to the ship.

Quoted from the Hubble Website:

When 17th-century astronomers first turned their telescopes to Jupiter, they noted a conspicuous reddish spot on the giant planet. This Great Red Spot is still present in Jupiter's atmosphere, more than 300 years later. It is now known that it is a vast storm, spinning like a cyclone. Unlike a low-pressure hurricane in the Caribbean Sea, however, the Red Spot rotates in a counterclockwise direction in the Southern Hemisphere, showing that it is a high-pressure system. Winds inside this Jovian storm reach speeds of about 270 mph.

The Red Spot is the largest known storm in the solar system. With a diameter of 15,400 miles, it is almost twice the size of the entire Earth and one-sixth the diameter of Jupiter itself.

 

[Supplement Four]

Originally posted by Maladominus:
Each time they skim the GG atmosphere, have a *small* chance to Encounter a Gas Giant Cloud Storm. You know? Like that HUGE Godzilla sized gas storm eyeball on the surface of Jupiter?

Yeah, man, yeah!! And, for story purposes, I'll have the players discover that one of the NPC passengers is painting these circle images all over the place that happens to resemble the eye of the storm in the gas giant...

...wait, I've seen that somewhere before...

(Mal, you know what I'm talking about...)

-S4

 

[Supplement Four]

Originally posted by Maladominus:
Each time they skim the GG atmosphere, have a *small* chance to Encounter a Gas Giant Cloud Storm. You know? Like that HUGE Godzilla sized gas storm eyeball on the surface of Jupiter?

Yeah, man, yeah!! And, for story purposes, I'll have the players discover that one of the NPC passengers is painting these circle images all over the place that happens to resemble the eye of the storm in the gas giant...

...wait, I've seen that somewhere before...

(Mal, you know what I'm talking about...)

-S4