Fuel Purification Plant

[boomslang]

Originally posted by far-trader:
So, you want to make orbit in your air/raft you're welcome to. It won't be a comfy trip, and it'll take a long time. You want to come back down in it you have two choices imtu, toasted or splattered

If there's an atmo, you'll burn up attempting reentry. If there's no atmo you'll hit the ground very very fast.

So... Free Traders are just SOL at Size 8+, Starport D- worlds, then?

 

[Supplement Four]

Dan,

Thanks for replacing this post from the Rules Index thread. I deleted my post as well.

Originally posted by far-trader:
If you're so sure of this, explain to me how the lowly air/raft and heavy g-carrier, each with far less than 1G of thrust is able to make orbit of any world, even a size 10?

That's right, it flies there, very slowly

OK, let's look at your question...

I would answer this by citing the CT vehicle design rules in Striker. There, it plainly states that grav craft must devote some of their G rating to just staying afloat and beating the world's gravity.

Any left-over G rating is used for to maneuver the grav craft, and it is this rating that actually rates the vessel in its description (the G of lift needed to beat the world's gravity is not part of its description rating).

The CT vehicle design rules in Striker plainly say that. And, this consistent whether you're talking about a grav belt, a G-Carrier, or even a starship (all mentioned on different pages of Striker design rules).

So, let me ask you this...

If you're so sure that this Escape Velocity Rule isn't canon, then...


1....Why do CT grav vehicle design rules in Striker read the way they do?

2....Why does Stiker, pg. 41 of Book 2 explicitly state that spaceships have to subtract the world gravity from their M-Drive ratings when figuring movement rates inside the world's atmosphere?

3....Why does Andy Lilly mention the Escape Velocity rule as he tweaks it in one of his Traveller articles in White Dwarf magazine? He thinks he's tweaking a real CT rule, right?

4....Why does the LKW still design his ships using this rule for official CT publication?

5....Why does the Book 2 space combat movement rules not allow a 1G ship to lift from a Size 8 world?

6....Why does Book 6 show escape velocity from a Size 8 world at something higher than a ship with a 1G drive can achieve?

7....And, are all the high ports and port-to-ground shuttle services only meant for unstreamlined starships when most of the ubiquitous Traveller designs are streamlined?

The evidence is certainly starting to mount that the Escape Velocity rule is indeed CT canon.

(This would be a great question to ask LKW if I were still on the TML. Anyone that cares to, and gets an answer, please report back.)

 

[Supplement Four]

Dan,

Thanks for replacing this post from the Rules Index thread. I deleted my post as well.

Originally posted by far-trader:
If you're so sure of this, explain to me how the lowly air/raft and heavy g-carrier, each with far less than 1G of thrust is able to make orbit of any world, even a size 10?

That's right, it flies there, very slowly

OK, let's look at your question...

I would answer this by citing the CT vehicle design rules in Striker. There, it plainly states that grav craft must devote some of their G rating to just staying afloat and beating the world's gravity.

Any left-over G rating is used for to maneuver the grav craft, and it is this rating that actually rates the vessel in its description (the G of lift needed to beat the world's gravity is not part of its description rating).

The CT vehicle design rules in Striker plainly say that. And, this consistent whether you're talking about a grav belt, a G-Carrier, or even a starship (all mentioned on different pages of Striker design rules).

So, let me ask you this...

If you're so sure that this Escape Velocity Rule isn't canon, then...


1....Why do CT grav vehicle design rules in Striker read the way they do?

2....Why does Stiker, pg. 41 of Book 2 explicitly state that spaceships have to subtract the world gravity from their M-Drive ratings when figuring movement rates inside the world's atmosphere?

3....Why does Andy Lilly mention the Escape Velocity rule as he tweaks it in one of his Traveller articles in White Dwarf magazine? He thinks he's tweaking a real CT rule, right?

4....Why does the LKW still design his ships using this rule for official CT publication?

5....Why does the Book 2 space combat movement rules not allow a 1G ship to lift from a Size 8 world?

6....Why does Book 6 show escape velocity from a Size 8 world at something higher than a ship with a 1G drive can achieve?

7....And, are all the high ports and port-to-ground shuttle services only meant for unstreamlined starships when most of the ubiquitous Traveller designs are streamlined?

The evidence is certainly starting to mount that the Escape Velocity rule is indeed CT canon.

(This would be a great question to ask LKW if I were still on the TML. Anyone that cares to, and gets an answer, please report back.)

 

[far-trader]

Originally posted by Supplement Four:
...goods taken on in orbit are delivered when placed in orbit around the destination world.

And of course the pira... er, merchant in me has always been looking for that elusive chance to capitalize since reading that line years ago.

You know, contract delivery of freight in orbit at a class A Highport bound for a backwater system with no Highport or shuttles. Boot it out the airlock over the planet and radio them to say "Your supplies are here."

"Oh, so now you want them safely on the ground? Sure, I can do that, how about Cr2000 per ton? In advance."

"No? Oh look! Salvage."

So, there is a bit of problem with that little rule not being thought out completely imo.

 

[far-trader]

Originally posted by Supplement Four:
...goods taken on in orbit are delivered when placed in orbit around the destination world.

And of course the pira... er, merchant in me has always been looking for that elusive chance to capitalize since reading that line years ago.

You know, contract delivery of freight in orbit at a class A Highport bound for a backwater system with no Highport or shuttles. Boot it out the airlock over the planet and radio them to say "Your supplies are here."

"Oh, so now you want them safely on the ground? Sure, I can do that, how about Cr2000 per ton? In advance."

"No? Oh look! Salvage."

So, there is a bit of problem with that little rule not being thought out completely imo.

 

[Supplement Four]

Originally posted by Supplement Four:
</font><blockquote>quote:</font><hr />Originally posted by boomslang:
Not necessarily; you can skim up where the air is rare (and the hydrogen is actually a higher percentage of what you encounter), if you just go fast enough.

A grav-propelled vessel's maximum effective ground speed is a function of atmo drag; less atmo, higher top speed in atmo. 1G is plenty to skim with; you just have to stay high and fast.

Just for clarification: CT rules do specify a deep dive into the atmo when skimming. Check out the Lesser Known Aspects of Space Travel section in your LBBs. </font>[/QUOTE]How close can a ship with a 1G drive actually dive into the depths of a gas giant?

Classic Traveller tells us on the STANDARD WORLDS table in Book 2.

Saturn is a big ball of gas with no solid "surface". It's diameter is 124,800 km. You can tell that by looking at the .25G column on the table. This distance is equal to one diameter of the world.

The distances in the chart show the G rating for each distance from the center of the planet (multiply distances by 100 to get distance in km).

When the distance is equal to the R column (Planetary Radius), the distance is on the world's surface. Note that GGs don't have "surfaces" but are given a R rating in the chart nonetheless.

So, to see how close a ship with a 1G M-Drive can get to a GG, simply look at the chart.

Saturn's gravitational grab of .25 Gs begins at 124,800 km from the planet's center (or 124,800 - 58,100 = 66,700 km from it's "surface").

At 88,300 km from it's center (30,200 km from it's "surface"), Saturn's gravitational pull jumps to .5 Gs.

At 72,100 km (14,000 km from it's "surface"), gravity jumps again to .75 Gs.

So, this is the limit a ship with a 1G M-Drive can dive into Saturn's atmosphere.




A question presents itself: How dense is Saturn's atmosphere at 72,100 km from it's center? Is there any hydrogen that far out to skim?

At 72,100 km, the ship would be just 14,000 km above the world's listed diameter. Since orbit of a Size 8 world is considered to be about 10,000 km out from the world's diameter, I'm assuming that 14,000 km out from a large gas giant is sufficient enough to skim fuel.

I may be wrong, though.



A statement presents itself: Saturn is a bad choice for skimming if you've got a ship with a 1G drive. Saturn is a large gas giant. If captains with ships rated at 1G stick to the smaller gas giants, like Uranus or Neptune, then they have a much easier time of it. "Surface" gravity of Uranus (gravity at its diameter) is less than 1G.

 

[Supplement Four]

Originally posted by Supplement Four:
</font><blockquote>quote:</font><hr />Originally posted by boomslang:
Not necessarily; you can skim up where the air is rare (and the hydrogen is actually a higher percentage of what you encounter), if you just go fast enough.

A grav-propelled vessel's maximum effective ground speed is a function of atmo drag; less atmo, higher top speed in atmo. 1G is plenty to skim with; you just have to stay high and fast.

Just for clarification: CT rules do specify a deep dive into the atmo when skimming. Check out the Lesser Known Aspects of Space Travel section in your LBBs. </font>[/QUOTE]How close can a ship with a 1G drive actually dive into the depths of a gas giant?

Classic Traveller tells us on the STANDARD WORLDS table in Book 2.

Saturn is a big ball of gas with no solid "surface". It's diameter is 124,800 km. You can tell that by looking at the .25G column on the table. This distance is equal to one diameter of the world.

The distances in the chart show the G rating for each distance from the center of the planet (multiply distances by 100 to get distance in km).

When the distance is equal to the R column (Planetary Radius), the distance is on the world's surface. Note that GGs don't have "surfaces" but are given a R rating in the chart nonetheless.

So, to see how close a ship with a 1G M-Drive can get to a GG, simply look at the chart.

Saturn's gravitational grab of .25 Gs begins at 124,800 km from the planet's center (or 124,800 - 58,100 = 66,700 km from it's "surface").

At 88,300 km from it's center (30,200 km from it's "surface"), Saturn's gravitational pull jumps to .5 Gs.

At 72,100 km (14,000 km from it's "surface"), gravity jumps again to .75 Gs.

So, this is the limit a ship with a 1G M-Drive can dive into Saturn's atmosphere.




A question presents itself: How dense is Saturn's atmosphere at 72,100 km from it's center? Is there any hydrogen that far out to skim?

At 72,100 km, the ship would be just 14,000 km above the world's listed diameter. Since orbit of a Size 8 world is considered to be about 10,000 km out from the world's diameter, I'm assuming that 14,000 km out from a large gas giant is sufficient enough to skim fuel.

I may be wrong, though.



A statement presents itself: Saturn is a bad choice for skimming if you've got a ship with a 1G drive. Saturn is a large gas giant. If captains with ships rated at 1G stick to the smaller gas giants, like Uranus or Neptune, then they have a much easier time of it. "Surface" gravity of Uranus (gravity at its diameter) is less than 1G.

 

[far-trader]

Originally posted by Supplement Four:
So, let me ask you this...

If you're so sure that this Escape Velocity Rule isn't canon, then...

Thing is I'm not

In fact I've long been convinced it shouldn't be. First time we did vector combat ages ago the incongruity(?) of the way we simply ignored it for landings hit me hard which is why I recalled the rule there. But we didn't do vector combat much and we landed all the time so we picked the simple solution and ignored it

So I'm just here playing devil's advocate to help you build a strong case for it. Not that it seems to be needed. The case is already pretty convincing.

 

[far-trader]

Originally posted by Supplement Four:
So, let me ask you this...

If you're so sure that this Escape Velocity Rule isn't canon, then...

Thing is I'm not

In fact I've long been convinced it shouldn't be. First time we did vector combat ages ago the incongruity(?) of the way we simply ignored it for landings hit me hard which is why I recalled the rule there. But we didn't do vector combat much and we landed all the time so we picked the simple solution and ignored it

So I'm just here playing devil's advocate to help you build a strong case for it. Not that it seems to be needed. The case is already pretty convincing.

 

[far-trader]

I always figured GG skimming is cloudtop, i.e. its diameter, give or take a little. I seem to recall the problem is not the gravity but the atmo pressure which rises very quickly, deep being a relative term. But I could be wrong.

 

[far-trader]

I always figured GG skimming is cloudtop, i.e. its diameter, give or take a little. I seem to recall the problem is not the gravity but the atmo pressure which rises very quickly, deep being a relative term. But I could be wrong.

 

[Supplement Four]

Originally posted by far-trader:
But we didn't do vector combat much and we landed all the time so we picked the simple solution and ignored it

And, certainly it's been ignored or handwaved in other editions of Traveller.

MT brings out the idea of the ship's maneuver drive being put into "overdrive" for short periods of time--problem solved.

It's been a long time since I've looked at TNE, but doesn't it have a contra grav that pushes against local gravity like two like poles of a magnet?

Other GMs cite aerodynamic lift to "help" the ship keep afloat.

I'm sure I'm forgetting something.

My guess is that this idea has been dropped because it's really rather persnickety. It might be viewed as bothersome or too difficult to explain easily for the game rules. Thus, a handwave is made, and it's no longer a problem (nothing wrong with a good handwave, btw. I like a good handwave if its logical and believeable).

What I like about the rule, and why I'm keeping it in my game, is that, imo, it makes the OTU that much more rich.

A tramp freighter captain's got a choice. Cargo shippers and passengers have got a choice. It lends itself to the details that makes up a good, believeable universe to game in.

"You see what Petersoni did? He went and upgraded his drives! He's pushin' 2 Gs now. We'll never be competition for him now!"

"Hi. I'm Ami. Me and my husband are looking for quiet transportation offworld. Here, take these vochers. We need to be set down not at the starport, though. There's this ranch, on a different continent. Can you take us there?" As the ship's captain looks at the library data on the destination world and sees its a size 9 planet.."

I see all kinds of goodness coming out of this type of game play.

I like it a lot.

The case is already pretty convincing.

I agree. It's canon alright. But, it's dying canon. It's only CT canon--not for any other version.

Hey...it's our own canon! Our own little piece of canon that CT can call its own!

 

[Supplement Four]

Originally posted by far-trader:
But we didn't do vector combat much and we landed all the time so we picked the simple solution and ignored it

And, certainly it's been ignored or handwaved in other editions of Traveller.

MT brings out the idea of the ship's maneuver drive being put into "overdrive" for short periods of time--problem solved.

It's been a long time since I've looked at TNE, but doesn't it have a contra grav that pushes against local gravity like two like poles of a magnet?

Other GMs cite aerodynamic lift to "help" the ship keep afloat.

I'm sure I'm forgetting something.

My guess is that this idea has been dropped because it's really rather persnickety. It might be viewed as bothersome or too difficult to explain easily for the game rules. Thus, a handwave is made, and it's no longer a problem (nothing wrong with a good handwave, btw. I like a good handwave if its logical and believeable).

What I like about the rule, and why I'm keeping it in my game, is that, imo, it makes the OTU that much more rich.

A tramp freighter captain's got a choice. Cargo shippers and passengers have got a choice. It lends itself to the details that makes up a good, believeable universe to game in.

"You see what Petersoni did? He went and upgraded his drives! He's pushin' 2 Gs now. We'll never be competition for him now!"

"Hi. I'm Ami. Me and my husband are looking for quiet transportation offworld. Here, take these vochers. We need to be set down not at the starport, though. There's this ranch, on a different continent. Can you take us there?" As the ship's captain looks at the library data on the destination world and sees its a size 9 planet.."

I see all kinds of goodness coming out of this type of game play.

I like it a lot.

The case is already pretty convincing.

I agree. It's canon alright. But, it's dying canon. It's only CT canon--not for any other version.

Hey...it's our own canon! Our own little piece of canon that CT can call its own!

 

[boomslang]

Originally posted by Supplement Four:

So, this is the limit a ship with a 1G M-Drive can dive into Saturn's atmosphere.

You are completely overlooking the fact that even a 1G vessel can make an approach to a GG (of any size) with an arbitrarily huge vector already built up. All the GG's gravity does is deflect the vector more or less (into a hyberbolic orbital path, technically); the only thing that you have to worry about is countering the aerobraking effect from the atmo. And the more aerobraking that occurs, the more intake pressure your scoops will see, so all you have to do is keep the drag you encounter under 1G and you'll whip out the other side of the run still moving at a good speed. Indeed, if you plot it correctly -- approaching from the orbitally-trailing hemisphere of the GG -- you can even get a slingshot effect from adding the GG's vector to your own...

 

[boomslang]

Originally posted by Supplement Four:

So, this is the limit a ship with a 1G M-Drive can dive into Saturn's atmosphere.

You are completely overlooking the fact that even a 1G vessel can make an approach to a GG (of any size) with an arbitrarily huge vector already built up. All the GG's gravity does is deflect the vector more or less (into a hyberbolic orbital path, technically); the only thing that you have to worry about is countering the aerobraking effect from the atmo. And the more aerobraking that occurs, the more intake pressure your scoops will see, so all you have to do is keep the drag you encounter under 1G and you'll whip out the other side of the run still moving at a good speed. Indeed, if you plot it correctly -- approaching from the orbitally-trailing hemisphere of the GG -- you can even get a slingshot effect from adding the GG's vector to your own...

 

[Supplement Four]

Originally posted by far-trader:
I always figured GG skimming is cloudtop, i.e. its diameter, give or take a little. I seem to recall the problem is not the gravity but the atmo pressure which rises very quickly, deep being a relative term. But I could be wrong.

You're probably right and wrong.

You're probably right in that real science would figure in pressure, wind shear, and things that go bump in the atmo.

You're probably wrong in that Traveller science glosses all this over and looks solely at the G rating of the planet. It's the whole play balance vs. persnickety detail thing.





Curious: Does anybody know the density of hydrogen at a gas giant's diameter?

Does a ship have to dive deeper, past the planetary diameter, in order to skim fuel?

Or, is there enough hydrogen escaping the planetary diameter that some altitude greater than the planet's diameter is all that is necessary to skim fuel.

Any astronomers here that can answer those science questions?




Or, even this question: Earth has an atmosphere that stretches several thousand kilometers past its diameter.

Does the same hold true for a gas giant? Does a gas giant have an "atmosphere" that stretches past it's official diameter?

Or, since the GG is a big ball of gas, does the GG diameter actually measure where atmosphere ends and oribital open space begins?

Anyone know the answer to that question?

 

[Supplement Four]

Originally posted by far-trader:
I always figured GG skimming is cloudtop, i.e. its diameter, give or take a little. I seem to recall the problem is not the gravity but the atmo pressure which rises very quickly, deep being a relative term. But I could be wrong.

You're probably right and wrong.

You're probably right in that real science would figure in pressure, wind shear, and things that go bump in the atmo.

You're probably wrong in that Traveller science glosses all this over and looks solely at the G rating of the planet. It's the whole play balance vs. persnickety detail thing.





Curious: Does anybody know the density of hydrogen at a gas giant's diameter?

Does a ship have to dive deeper, past the planetary diameter, in order to skim fuel?

Or, is there enough hydrogen escaping the planetary diameter that some altitude greater than the planet's diameter is all that is necessary to skim fuel.

Any astronomers here that can answer those science questions?




Or, even this question: Earth has an atmosphere that stretches several thousand kilometers past its diameter.

Does the same hold true for a gas giant? Does a gas giant have an "atmosphere" that stretches past it's official diameter?

Or, since the GG is a big ball of gas, does the GG diameter actually measure where atmosphere ends and oribital open space begins?

Anyone know the answer to that question?

 

[Supplement Four]

Originally posted by boomslang:
You are completely overlooking the fact that even a 1G vessel can make an approach to a GG (of any size) with an arbitrarily huge vector already built up.

You, sir, are absolutley correct. I was overlooking that fact.

Thanks for setting me straight.

 

[Supplement Four]

Originally posted by boomslang:
You are completely overlooking the fact that even a 1G vessel can make an approach to a GG (of any size) with an arbitrarily huge vector already built up.

You, sir, are absolutley correct. I was overlooking that fact.

Thanks for setting me straight.

 

[far-trader]

Originally posted by Supplement Four:
...What I like about the rule, and why I'm keeping it in my game, is that, imo, it makes the OTU that much more rich.

I agree, and for that reason alone it'll probably be used if I ever get a game going again. Choices are always fun.