Brown Dwarf Refuelling Points?

[aramis]

Here's a thought: A fast enough pass through the exosphere with a wide-mouth scoop should be able to skim even from massive systems. The trick being to have escape velocity post collision with the exosphere. If you're going fast enough, you can easily compress enough to skim without significant direct resistance; you're exit course will of course be WILDLY different.

Essentially, staying above the cloud-tops, and doing a gravity slingshot dipping into just enough atmosphere to pressurize.

Even a tiny error, however, could be catastrophic.

 

[Malenfant]

Such a pass would destroy the ship.

You can have up about 200G to deal with here, at the cloudtops - that's problem number one. You're going to be coming in extremely fast because of that. On top of that, you have the high temperature of the cloudtops, not to mention possible particulates (silicon or iron particles in the clouds) hitting you when you come in. Plus the general problem of just plain burning up/being torn apart by drag stresses as you enter the atmosphere. Plus entering the atmosphere itself causes drag which would alter the flightpath.

So no, it's not really possible at all.

Glad you found the article useful, CardinalBiggles

 

[aramis]

Who's aiming at cloudtops?

Exosphere is probably at least a hundred km above that, probably more. The area that is, for most purposes, vacuum. The area that is probably high-temperatures hydrogen, and some helium, that is while still trapped, energetic and above the visible troposphere. A high speed pass should be able to grab enough by "movement imposed artificial density", to get the desity up to mols per mL at scoop...

Please, Read what I write, not what you read into it...

 

[Malenfant]

so? 100 or 200 km above the cloudtops, the gravity is still way above 6g and it's still possibly fairly hot. It's still not possible.

 

[Liam Devlin]

Mal--thanks for the link to your paper on BD's. Fills in something we might all use.

Frankly, I was surprised to discover they were more common than previously known!

Once again, thanks fer the data for us all!

 

[Malenfant]

yer welcome

 

[Liam Devlin]

Mal--a question [and not being a JTAS subscriber] on BD's in stellar generation:

Should we treat them like Dwarf stars for possible number of orbiting bodies?

 

[Malenfant]

I thought you'd read the article...?

Basically they're like gas giants for satellite placement, except the size of moon is generated like a planet.

 

[Liam Devlin]

Thanks Mal. Appreciate it!

And I read the link's opening part--you have to be a subscriber to get the rest.

 

[kafka47]

Then what was the point of having Brown Dwarfs as discharge points in 2300AD? I always assumed that it was because there were too few stars between Kafer space and the French Arm? How did Brown Dwarfs act as a Back Door?

Would we generate these as Stars or just Super Jovians? As I plan to include one of these on the adventure that I am running on the Board. How would we calculate habitable zones and all? Preferably using the MT rules or Scouts.

 

[Malenfant]

I can't really say any more about generating BDs that what's in the article - I can't reprint the information therein wholesale without violating SJG's copyright on the article. Which is fair enough.

However.

I can't see any problem with me providing a link to this Excel file that I compiled entirely from one of the science papers* I referenced therein, which shows all the useful vital statistics of the full range of BDs and how they evolve in time from formation to about 12 billion years in age.

*: The source paper for those numbers is - The Theory of Brown Dwarfs and Extrasolar Giant Planets, Burrows et al., Reviews of Modern Physics, volume 73, 719-765 (2001).

Doesn't tell you much about satellites, superjovians, habitable zones, ring systems etc - for that you'd need the whole article, which you'd have to get from JTAS. But at least this general data on the BDs themselves could still be useful.

 

[kafka47]

Fair enough, I wouldn't want you to violate copyright...even though putting up a table would be considered Fair Use, if it cited the original article as the source.

I guess I will have to wing it. I guess the worlds contained within will suffer from a vastly different set of tempetures for the habitable zone. I need to design an ice world with a breathable atmosphere...the brown dwarf is thrown in for colour & possible excitement later on.

 

[Malenfant]

Times like this I wish SJG would do the sane thing and let people buy JTAS issues individually, or buy specific articles.

 

[TKalbfus]

"Brown Dwarfs get no respect! Its always those uppity white dwarfs that are always looking down on the dwarfs of a different color! I tell you their ain't no justice in the Universe."

 

[Rossoneill]

I dont think putting up a table is fair use as fair use is a copy for personal use only made from a copy you own or a small amount,up to a chapter and 25 copies or less for a teacher or small sections quoted for a review or a reviewer .
Putting up a copy on the internet for someone else to use has not been defined as fair use.
As a site on the internet is potentialy unlimited copies it is not fair use .
At least thats what my 30 years in Printing and copying and understanding of copyright law tells me .
I am sensative to this as the law for my position says if I violate this it can be up to $5,000 fine and up to 5 years in prison .
I could be wrong as SJG might have a slightly different wording on the fair use policy .

 

[kafka47]

My God, copyright is radically different between Canada & the US on this point. Fair Use would imply not a complete reproduction of a piece. A portion may be copied so long as the original work is cited, as the source and infringement of the original is not the intent.

With laws like that in the States, it is a wonder that anything ever gets done! Long live the differences! Vivre la difference!

Not advocating wholesale piracy here but rights holders have to a degree of reasonableness and reason...

 

[Sifu Blackirish]

Sigg Oddra said:

In the Imperium and Dark Nebula games tanker squadrons could manufacture fuel from stars - this idea has never been repeated in the OTU.

Wow! Did they ever give any sort of explanation or just handwave it away?

Malenfant said:

I think my ideal scifi RPG would be hard as hell in terms of the universe (as realistic as possible), but with strong, possibly larger-than-life characters to drive the game on. I don't believe that these are mutually exclusive concepts - you could have space opera like characters in a universe that is physically realistic.

Absolutely right. It is the characters that drive the adventure, not necessarily fancy hardware.

kafka47 said:

Then what was the point of having Brown Dwarfs as discharge points in 2300AD? I always assumed that it was because there were too few stars between Kafer space and the French Arm? How did Brown Dwarfs act as a Back Door?

(guaranteed non-expert opinion)
Having never played 2300AD or done more than read the occasional Challenge article, I am just guessing...but here goes.

It was necessary to discharge the FTL drives in a gravity well before the 7.7 LY limit. I would say that everyone assumed BDs with no habitable planets were of no value, but now the Americans are using them as transit pointsto reach beyond the 'dead' areas of their arm.

 

[mike wightman]

Originally posted by Dominion Loyalty Officer:
Wow! Did they ever give any sort of explanation or just handwave it away?

Handwave only I'm afraid

Tankers are mobile stations capable of manufacturing fuel directly from stellar atmospheres.

 

[Malenfant]

This was in Imperium?

Hm, IIRC Jon was somewhat influenced by that game for GT:Interstellar Wars. I'm guessing they just quietly tossed that part out of the window.

I guess that's where Bell and BRaben nicked the idea of stellar refuelling from for Elite though

 

[Whipsnade]

Originally posted by Dominion Loyalty Officer:(guaranteed non-expert opinion)
Having never played 2300AD or done more than read the occasional Challenge article, I am just guessing...but here goes.

It was necessary to discharge the FTL drives in a gravity well before the 7.7 LY limit. I would say that everyone assumed BDs with no habitable planets were of no value, but now the Americans are using them as transit points to reach beyond the 'dead' areas of their arm.

DLO,

Well, you may have never played 2300AD but you got that exactly right.

The brown dwarves in question are used only as stutterwarp 'gravity dumps'. Finding and using them allow the Alderhost Alliance to reach Ylii/Kafer space; i.e. Operation Backdoor, and allows the Americans/Australians to extend their Arm; i.e. the Beta Aquilae(sp) Cluster.


Dr. Thomas,

2300AD has finding BDs very difficult and time consuming. The Americans/Australians spend years looking for useful ones and even set up an Arm-wide interferometry network for the task. How accurately does that match the real world?


Have fun,
Bill