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Old 02-23-2020, 10:28 PM   #21
Rupert
 
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Default Re: Coolant [Spaceships]

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Originally Posted by Ulzgoroth View Post
I wouldn't say you need to be all that exotic. Pretty much apply air traffic control rules, but with system-wide control rather than only exerting control over relatively small envelopes around key areas.
Enforcement will need to be truly draconian, immediate (and if you have an accident that leaves you out of control and on a collision course with something important, tough luck), and thorough.
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Old 02-23-2020, 11:10 PM   #22
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Default Re: Coolant [Spaceships]

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Originally Posted by Ulzgoroth View Post
If you really want your reactionless drives to have limited delta-V, I'd question why you're using reactionless drives at all.
The problem with the Tyranny of the Rocket Equation is that sometimes you don't want anarchy, you just want a more tolerant regime. Replace the Tyrant with a more easy-going ruler.
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Old 02-23-2020, 11:23 PM   #23
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Default Re: Coolant [Spaceships]

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Originally Posted by Verjigorm View Post


I still haven't wrapped my head around it completely, but it seems like there is almost a need for a rather strict protocol for spaceship ownership and operation.
It'll need something. There are several different forms that something could take.

As for WMDs, a distinction needs to be made. 'WMD' covers everything from one-kiloton mininukes to R-bombs that can shatter planets.

Reasonable mass orbital and interplanetary vessels are certainly WMDs, but they tend to be WMDs on the lower end of the scale. Let's say you've got a 1000 metric ton ship moving at 100 kilometers/sec. That's a nice clip for interplanetary travel, beyond current state of the art.

It'll hit with a force of about 1 megaton, if I didn't slip a digit in my BOTEC. OK, that's certainly a WMD. It's as big as a biggish strategic nuke.

But the flipside of that is that we already have 1 megaton nukes. We've had them for over half a century. So such a ship doesn't really add anything to the picture that isn't already present, and it would be an inefficient way to deliver a 1 megaton boom compared to a nuke.

Such ships would imply very good space traffic control. There would be radar nets and other sensors tracking ships, trajectories would be filed and approved, etc. Ownership could be anything, as long as the operations are prevented from doing damage. But such vessels, which would be fully sufficient for a Solar System wide civilization, would not really change the WMD big picture much.

Where Jon's Law really starts to bite is when you start getting up into thousands of kilometers/sec, or ships with enormous masses.
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Old 02-23-2020, 11:50 PM   #24
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Default Re: Coolant [Spaceships]

How much would it help to have rather fragile (and not "streamlined") space ships that would break up in atmospheres? And while real life shuttles are "streamlined" they are still pretty fragile if not deorbited in just the right way so you'll use similar crafts (and elevators etc) to get up and down.
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Old 02-23-2020, 11:54 PM   #25
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Default Re: Coolant [Spaceships]

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Originally Posted by Johnny1A.2 View Post
Reasonable mass orbital and interplanetary vessels are certainly WMDs, but they tend to be WMDs on the lower end of the scale. Let's say you've got a 1000 metric ton ship moving at 100 kilometers/sec. That's a nice clip for interplanetary travel, beyond current state of the art.

It'll hit with a force of about 1 megaton, if I didn't slip a digit in my BOTEC. OK, that's certainly a WMD. It's as big as a biggish strategic nuke.
I check your BOTEC

Quote:
But the flipside of that is that we already have 1 megaton nukes. We've had them for over half a century. So such a ship doesn't really add anything to the picture that isn't already present, and it would be an inefficient way to deliver a 1 megaton boom compared to a nuke.
What does make a difference is that the control problem on a nuke is a lot easier than the control problem on an airliner. You can lock your strategic weapons away in guarded armouries, and exercise extreme vetting over the officers who control them. But freighters and passenger liners have to be out and about with all sorts of people having easy access to them.

In September 2001 I was running an SF campaign in which the PCs were involved in counter-terrorism in my usual Jon's-Law-obsessed interstellar SF setting. One of my players was from New York. I had to end the campaign abruptly.
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Old 02-23-2020, 11:55 PM   #26
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Default Re: Coolant [Spaceships]

I tried to at least alleviate the WMD problem by cribbing from Poul Anderson et al:

Drives IMTU (In My Traveller Universe)

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Maneuver drive (M-drive) (TL9) moves a ship through space without perceived acceleration. It does not create kinetic energy. If the drive field around the ship hits large amounts of matter the breakers pop or the drive explodes or melts down. Any increase in potential energy is provided by the ship's power plant. Any decrease in potential energy turns into heat. When the drive turns off the ship resumes the intrinsic velocity it had before the drive turned on*.

To change your intrinsic velocity you need a source of thrust, or to play games with M-driving into a gravity field, turning off the M-drive while you fall, turning it back on to climb up, etc.

Thrust engines (T-drives) exists in a myriad of forms at different tech levels, but most starships use a standard type which uses power from the ship's power plant to heat up reaction mass and shoot it out a nozzle in the desired direction. The reaction mass is usually the surrounding atmosphere, or onboard hydrogen, although other onboard types of reaction mass can be used. This exhaust is often very hot, but a cooler mode is available so you can land in the bush without starting a forest fire.

The acceleration from T-drives is experienced normally, there is no easy way to counteract it.

(Air rafts and such also need a source of thrust besides their anti-gravity.)

Yes, these means ships have three kinds of drives, not two. For purposes of skills, feats, etc, any of them apply equally to M-drives and T-drives.


* Yes, I know I am creating a preferred reference frame, and time travel. I have a waiver here signed by Aristole, Newton, Einstein, Hawking, Cochrane, and both Popes. Go away.

(Yes, it is somewhat like the stutterwarp from 2300 AD, though I am largely cribbing from Poul Anderson.)
(Three drives is because I also discussed the FTL drives.)
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Old 02-24-2020, 12:07 AM   #27
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Default Re: Coolant [Spaceships]

My plan is to have the m-drive kill your velocity relative to any large mass 'nearby', to avoid tricks involving building up huge vectors some-place else, and then lining up the ship and turning off the m-drive (a trick you can do with 2300AD-style stutterwarps and the like, if you've the patience).

This also gets around questions about matching orbital velocities with planets and adjusting for relative stellar velocities when your main drive doesn't add real velocity.
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Old 02-24-2020, 12:15 AM   #28
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Default Re: Coolant [Spaceships]

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Originally Posted by Bengt View Post
How much would it help to have rather fragile (and not "streamlined") space ships that would break up in atmospheres?
Some, particularly if you can ensure a shallow angle of entry. Until you get into really big bangs an iceball exploding at 114 000 feet isn't going to do a lot of damage on the ground.

Here's the Earth Impacts Effects Calculator. It's really intended for meteors and asteroid impacts, and if you model spaceships as chunks of ice they don't seem too terrifying.

However, your spaceship security has to contend not only with spaceships that are in space deciding to land without retrorockets, but also with spaceships with enough fuel and propellant to fly to Mars deciding to take off into the side of a government building instead of into space.
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Old 02-24-2020, 01:41 AM   #29
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Default Re: Coolant [Spaceships]

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Originally Posted by Rupert View Post
Enforcement will need to be truly draconian, immediate (and if you have an accident that leaves you out of control and on a collision course with something important, tough luck), and thorough.
We're talking about real space problems, so 'accidentally on a collision course with something important' is a negligible case. 'Deliberately on a collision course with something important but accidentally lost the ability to get off it' is a little less so, but not allowing interplanetary flight plans that have a suicide burn at the end isn't exactly a hard concept.

Also in real space factors, the distances of any trip aren't short, and the times aren't all that short as a result. You only need immediate enforcement if somebody is going to plow into something at kps on the same level of immediacy, and you should never have allowed a flight trajectory that would let them abruptly change from 'safe' to 'ramming' in anything close to your reaction times in the first place.

Any kind of enforcement of anything needs to be thorough, in proportion to the degree that you actually want to prevent it rather than occasionally using it to justify doling out punishments. You probably do genuinely want to prevent hyper-velocity kinetic strikes, so yeah. And the fact that no modes of interaction between 'talk to them' and 'destroy them' are really possible with a ship at high relative velocity, 'draconian' is the only option on the table. That said, both of these things apply to ATC as well, and they scarcely ever ask for a plane to be shot down and usually are not considered irresponsible in that practice...



There is a space where you've got pretty short time-frame problems if you have high-thrust main drives. At some point many ships want to come very close indeed to potentially delicate space habitats. If our 100-ton suicidal shuttle has 1g acceleration and suddenly burns from rest towards a hab 35 km away, it won't be going at ridiculous speeds when it gets there a minute later but 500+ m/s is probably plenty to cause some major damage.
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Originally Posted by Bengt View Post
How much would it help to have rather fragile (and not "streamlined") space ships that would break up in atmospheres? And while real life shuttles are "streamlined" they are still pretty fragile if not deorbited in just the right way so you'll use similar crafts (and elevators etc) to get up and down.
If you don't know for sure what's inside the spaceship, there's the concern that the same people responsible for its trajectory have given it a high-density atmosphere-penetrating payload. If they're not too picky about accuracy they won't even need to release it instead of letting it find its own way out when the ship hits atmosphere.

Although with reasonable information you should be able to judge the total payload mass, you probably can't externally tell whether it's a 100 ton cargo of plastic sheets or a 100 ton tungsten cannonball.
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Originally Posted by Johnny1A.2 View Post
The problem with the Tyranny of the Rocket Equation is that sometimes you don't want anarchy, you just want a more tolerant regime. Replace the Tyrant with a more easy-going ruler.
The OP's proposal literally keeps the rocket equation in! The only thing it changes is not having a high-energy exhaust stream.
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Old 02-24-2020, 02:01 AM   #30
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Default Re: Coolant [Spaceships]

No. I would not use coolant. My explanation for why my reactionless engines have an upper speed limit is that interacting with the dark matter that they use for virtual propellant creates drag and at at sufficiently high speed drag equals thrust.
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