cthia wrote:You did suggest the possibility first but you didn't show much confidence in it. You spirited collecting from cometary ices and planets because it was 10,000 times more dense than a molecular cloud and thusly far more denser than surrounding space. In other words, you suggested it to be possible but you then proceeded to argue that it wasn't probable. Textev is also of benefit to you it seems.
Ice is not 10,000 times denser than a molecular cloud. That is the ratio between a molecular cloud and the interplanetary medium. The ratio between the hydrogen densities of a molecular cloud and ice is 10,000,000,000,000,000. Quite a few orders of magnitude larger. It makes a big difference.
But textev, regarding the Honorverse anyways, clearly states that surrounding space is the source used.
Actually, what the text says is that gas catchers can be used to gather hydrogen from space if a ship doesn't have other sources. And it says that they used to do it at a time when ships did not have impellers, and had to use fusion rockets for propulsion (and lots of hydrogen!), and interstellar travel took months or years without any opportunity for refueling at a star system.
The text does not say that this was the primary or preferred source of hydrogen even back then. Nor does it say that gas catchers are still used, though I'm certain that they are used in some circumstances. At the very least, I'm sure ships have that capability as a backup.
The text certainly does not say that "surrounding space is the source used." I argue that it has always been a secondary or tertiary source, a solution when you were nowhere near a better source like a cometary system or ice planet and are desperate to refuel. That certainly would describe those old hydrogen-hog fusion-drive ships six months from any star system with a fueling station.
Again.
Collection from planetary and cometary ice sources would suffer lagging production compared to surrounding space, from the many man hours required in the collection and the further time lost in the often overlooked 'conversion and filtering' process. The same often overlooked process regarding the complaints about municipalities, such as LA, suffering water shortages that are sitting right on the coast! See appropriate post. I've cued the link to begin with my appropriate post.
You keep making the same mistake as people that used to complain to me when I was fresh out of college working as an Engineer at a water department. "Why is there a water shortage when the city is on the ocean?" And collecting water from water should be laughably easier than collecting hydrogen from cometary ices and planets. Yet there are water shortages in LA all of the time. Even when the source (Ocean) is literally beating against the back door of the plants!
It's the conversion process! Surrounding space facilities would eliminate the time lost in the collection. And totally eliminate the time lost from the constrained conversion processes. In fact, the non-polar characteristics of hydrogen (only) would assist systems to easily target it. Hydrogen would race to the collectors!
viewtopic.php?f=1&t=6589&start=61
I'm not sure why you are harping on the non-polar characteristics of hydrogen. Molecular hydrogen is not the only non-polar molecule--it is only the lightest non-polar molecule. And most of the hydrogen and other atoms in a nebula will not be in a molecular form--it will be ionized, so polarity is irrelevant. The easiest way to separate the hydrogen from other atoms in a molecular cloud is to ionize all of it and separate by mass/charge ratio.
And that is also the easiest way to separate the hydrogen in ice, when you have the technology of the Honorverse. So the separation mechanism is similar, but the mechanism for gathering the material is much cheaper on a comet. I say it takes fewer man-hours to gather a ton of hydrogen from ice than it takes to gather a ton from nebular gas, and ice can be done with cheaper equipment.
Some of the skeptic's posts...
As you have unbreakable force fields and tractor rays, mining for hydrogen the local star comes to mind as the practically inexhaustible alternative.
Mining a profound vacuum is unlikely to be useful in most cases. Unless you need a hydrogen supply right there in the vacuum.
Or to put it another way, if the density of hydrogen in a nebula is sufficiently large to justify mining it, it has already coalesced into a star.
I am sure there are a few others, but I'm confident in your ability to find them if you need.
I frankly don't see the problem in these posts. All of those boil down to exactly what I said--that there are better sources available than interstellar space. Those posts are all talking about mining clouds on a large scale such as you have suggested, and saying that it is not efficient enough to compete with sources inside a planetary system. The text about gas catchers only talks about using them to refuel in-flight, between systems. None of those posts say that is impossible--in fact, one of them specifically notes that it might be useful if you needed fuel out there. So I don't see any contradiction to what I said.
The argument has always been that collecting hydrogen from a molecular cloud doesn't make sense
compared to other sources. If there is no other source, as in those old fusion-drive ships in the middle of nowhere, you use what you can get.
As far as I can tell, no one disagreed that hydrogen could be collected from space. It's just that it is even easier to do it from ice, which is plentiful in any planetary system. The hydrogen found on a comet is 10,000,000,000,000,000 times denser than the core of a giant molecular cloud or Bok globule, the densest kinds of nebulae.