Armies of the Fifth Frontier War, Impressions Not Errata

[Sigtrygg]

In original CT ships maxed out at 5000t and were driven by reaction drives.

You could not carry enough fuel to make near c rocks a thing, the m-drives wouldn't move them at all.

Then came magic reactionless drives and the unintended consequences started...

 

[Vormaerin]

And then trying to fix the unintended consequences they invent "space magic drives stop working in deep space". And that breaks some other things, so they invent a new thing that undoes the 'stops working in deep space' thing....

 

[MasterGwydion]

More fuel for M-Drives and massively cut down the required amount of jump fuel.

 

[Galadrion]

I don't think an inbound asteroid from another system would be easy to detect. It likely won't occlude anything because it would not need to be big - and even a big planet would not occlude anything on this scale. It would'nt take THAT long to get there, depending on the size of the M drive, but if you manage 1G, then it would take about 1 year to accelerate to just below light speed and 1 year per light year - 3,26 years per parsec. So, not decades but long enough that the war will likely be over, but we are just doing this for spite. In the final approach, it would start occluding stuff, but by then it would be coming in so fast, it would be barely behind the light waves you detect it with - you'd have maybe seconds to detect, target and decide to shoot it, most likely just enough time to say "oh fuck!". Accelerating all the way or at more than 1G would only make it arrive marginally faster, but would give it more and more potential energy, and also reduce reaction times on the planet. And when it hit, it would shatter the planet. This is the Dark Forest weapon.

The ONLY counter I can think of would be if it passed a ship enroute and that ship jumped to warn the target planet, basically 0 chance, since the ship would have to be sitting well out in the Kuiper Belt, in the right position to see it go by. The other possibility is to get lucky and see it leave from its origin system, in which case just jump out and put something - anything - in its path and boom!

But as to your thoughts on rock dropping, I agree this could be the calculus. It seems like it would differ based on local conditions - how many rocks? where are they? have the defenders prepared them with defenses or not? Likely in lots of cases, dropping rocks wouldn't really be a factor for a variety of reasons, but in some cases it might be important. This is interesting because it makes the whole star system into a theater of combat with need for lots of different kinds of ships, and maybe even marines and other capabilities.

It would be easier to detect than you think, but not from occlusion. An interstellar rock starts emitting hard radiation from collisions with interstellar gas well before its velocity reaches 0.0002 c - a speed which would mean the rock would take more than 15 millennia to cross a single parsec. Higher velocities would mean more, and higher-energy, emissions - by the time you get up to, say, 0.85 c you're talking about an energy beacon which would stand out to any space-capable society.

Now, doing anything about the incoming rock may be a different matter, but detecting it wouldn't be difficult.

Edited to correct a slipped decimal point.

 

[MonsterX]

And then trying to fix the unintended consequences they invent "space magic drives stop working in deep space". And that breaks some other things, so they invent a new thing that undoes the 'stops working in deep space' thing....

Patches get patches, and then these patches get their own patches, it is the cycle of nature.

Great fleas have little fleas upon their backs to bite 'em,
And little fleas have lesser fleas, and so ad infinitum.
And the great fleas themselves, in turn, have greater fleas to go on;
While these again have greater still, and greater still, and so on.

Augustus De Morgan Siphonaptera

 

[MonsterX]

It would be easier to detect than you think, but not from occlusion. An interstellar rock starts emitting hard radiation from collisions with interstellar gas well before its velocity reaches 0.0002 c - a speed which would mean the rock would take more than 15 millennia to cross a single parsec. Higher velocities would mean more, and higher-energy, emissions - by the time you get up to, say, 0.85 c you're talking about an energy beacon which would stand out to any space-capable society.

Now, doing anything about the incoming rock may be a different matter, but detecting it wouldn't be difficult.

Edited to correct a slipped decimal point.

See this is what forum discussions are all about, there is often someone around who thinks things through to the next step, or knows a fact that turns the discussion in a different direction.

So, given this fact, you've probably got months to react - at some fraction of light speed it starts to become visible, but at that fraction the projectile is not THAT far behind the light itself. Still, it is far enough that you've got time to organize an interception. Accelerating at higher Gs would therefore significantly decrease the warning time, but it still would be enough that spacecraft could react, probably in sufficient time to jump out to intercept: they would probably need a week plus some days warning, and it sounds like they would have that. The further out you intercept, the less of a smack you need to give the object to deflect it. The key variable is how quickly you can get up close to light speed, as the faster you do that the less time between the point at which radiation starts being emitted by the object, and the time when you are basically able to keep pace with this radiation.

You can imagine a scenario where interception would fail, but I think if you have a fleet of warships certainly you could manage it, and maybe also with freighters or whatever.

And that would be the solution: smash it like the DART probe to ruin its aim. The collision would have enormous energy and destroy the object's M drive, which would make readjusting it back on course impossible.

 

[collins355]

Sigh. It always ends up in a rocks down the gravity well discussion. This thread has literally almost word for word recreated parts of the mega thread on TML in the 1990s. But I’m assuming this is new territory for some participants.
TLDR there is no answer, just suspension of disbelief.
GDW created a whole new version of Traveller that changed the setting in horrendous ways (TNE) in an effort at least in part to address the rocks with reactionless drives issue. Instead they gave us heplar drives that both broke the setting and the laws of physics.

 

[MonsterX]

Sigh. It always ends up in a rocks down the gravity well discussion. This thread has literally almost word for word recreated parts of the mega thread on TML in the 1990s. But I’m assuming this is new territory for some participants.
TLDR there is no answer, just suspension of disbelief.
GDW created a whole new version of Traveller that changed the setting in horrendous ways (TNE) in an effort at least in part to address the rocks with reactionless drives issue. Instead they gave us heplar drives that both broke the setting and the laws of physics.

I think there ARE answers based on the assumptions, if you work things through, but you can often change the assumptions in order to get the game you want. So it is good to figure the implications of the assumptions, so you can be careful about the assumptions you make. Not assuming reactionless spacedrives in the first place would have been very helpful in a number of ways, although torchships raise their own gaming challenges.

Also, I think you will find not everyone participated in the megathreads of the 1990s, or if they did they may not remember the precise details of what was discussed 30 years ago.

 

[Endie]

Pretty sure orbital bombardment doesn't care if you are underwater or not. Just keep throwing rocks. For an in-universe example, look at Drinax cerca 890

Does it say somewhere that Drinax suffered rock bombardment? I know the Pod Core book says that there the Aslan used nukes and virus weapons, and Finale has one of the ships turn up that was used to fire on the planet, but I don't remember anything about the Aslan accelerating rocks into Drinax.

 

[Endie]

Sigh. It always ends up in a rocks down the gravity well discussion. This thread has literally almost word for word recreated parts of the mega thread on TML in the 1990s. But I’m assuming this is new territory for some participants.
TLDR there is no answer, just suspension of disbelief.
GDW created a whole new version of Traveller that changed the setting in horrendous ways (TNE) in an effort at least in part to address the rocks with reactionless drives issue. Instead they gave us heplar drives that both broke the setting and the laws of physics.

The TML was insufferable for long periods in the 90s due to the endless, wearying, near-c rock discussion. But, like zoomers on reddit discovering every 18 months that Downey used blackface in Tropic Thunder, it restarts again and again. The latest JTAS issues had a godawful article on it.

As you say, the correct answer is just "it doesn't happen, people don't do it, so we can play Traveller without Charted Space looking like the Sindalians conquered it all."

Or Larry Niven's Footfall or Lucifer's Hammer.

Footfall was a good book. Thank you for reminding me of it.

You are right not to be as kind about Lucifer's Hammer, which was dreadful.

 

[MonsterX]

Twisted Sister famously sung "I WANNA ROCK!". But Twisted Sister sucked (or, if they still exist, Twisted Sister sucks - present tense - unless they developed their musical skills since the 1980s). I don't want any rocks.

I think the discussion is more about finding justifications for excluding them than figuring out how to include them, and since many people don't have good justifications to hand, it is useful to go over them, so we don't end up with people feeling like they need to have asteroid bombing planets to be realistic. With apologies to those who have been through this discussion in an earlier geological era.

 

[actionman]

The TML was insufferable for long periods in the 90s due to the endless, wearying, near-c rock discussion. But, like zoomers on reddit discovering every 18 months that Downey used blackface in Tropic Thunder, it restarts again and again. The latest JTAS issues had a godawful article on it.

This is the thread replaying a thread disguised as another thread.

 

[actionman]

The TML was insufferable

Yes, it was.