Did the MBS corner the market on trade?

Jonathan_S wrote:I think the bigger problem is good luck building shuttles that can mount the armor and rad shielding for exposure to interstellar medium at major fractions of c.

It's a short trip from one ship to the other. They won't be exposed to interstellar medium and radiation for more than a few hours. So it should be doable.

But while the colony ships could self-evidently handle the particle screening needed for centuries of that velocity I doubt you'd want to expose crew in a shuttle to it. Sure if you have a formation of ships coasting along at the same velocity the shuttle should have the delta-v to move between them. But that's not so useful if you cook the crew (or impact a grain of dust and vaporize the shuttle)

There's no evidence they did, at least not the type of particle shielding that we see in modern ships. Since this is before impellers, it's also before gravitics that would allow for a gravitic barrier.

The shielding is probably just armour with large water tanks surrounding the inner hull.

That said, you're right a shuttle couldn't mount whatever shielding the mothership would. But it also has a much smaller volume to shield, and meteor impacts would be proportional to cross-section area and to the time it spends in space. That's also true for radiation dosages.

The shuttle only needs to be out in space for a few hours at a time. The mothership needs to endure 5.5 million hours.

And you may not need to send people over at all, short of a catastrophic problem aboard one of your ships. An automated robotic tug could deliver any replacement parts the other ship would need. They're also all within half a light-second of one another, so telepresence work should be possible too (and you can always nudge the ships a little bit closer if you need to decrease the lag).

tlb wrote:If they are coasting, then no one is going to fall behind. I think it is just the economics of one big ship over several smaller ones. Any problems would have to be fixed by the tools and machines at hand. Calvin's Hope only had the problem of fuel, but there was still enough to get them to another planet.

ThinksMarkedly wrote:Calvin's Hope was an example of reckless planning. They did not have an alternate planet to go to if things didn't turn out exactly as planned. It should at least have launched with the ability to refuel. It's mostly hydrogen you need, so getting it from a gas giant in the Calvin system should have been in the plans, so they could redirect and get back up to interstellar speed.

Anyway, this example shouldn't be used as your typical colony example. That's why I argued that the Manticore Colnisation Corporation should have sent more ships, because that one wasn't a reckless endeavour.

Why in space (if not on Earth) would you think that it would be easy to get hydrogen from a gas giant in the days before contra-gravity? They would expend much of the fuel just trying to escape the gravity well.

Why shouldn't it be a good example? They actually had an alternative. There is no way to plan for such a disaster, from the distance that they had to travel.

ThinksMarkedly wrote:

penny wrote:Water in space is not going to be as plentiful as that on the ground. Already filtered and untouched for millennia. Potable water! Enough to bathe and swim in! Enough to water a lawn.

Water in space is more plentiful than on Earth and, by definition, Earth-like planets. If you stray from Earth-like into hycean or pan-thalassan worlds, then you may have more water... but also less solid, dry ground too.

Since I do not wish to reinvent the wheel, I will repost this from quite some time ago from another thread. People oftentimes forget how things work in the real world. Potable water is the goal!

Again.

Collection from planetary and cometary ice sources would suffer lagging production 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!


You are 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?"

Collecting water from water should be laughably easy. 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!

Desalination has been around for thousands of years. The Egyptians were doing it essentially the same way we are doing it today, called thermal distillation whereby we evaporate water and recondense it, leaving the salt behind.

Actually, the process mimicks nature, which evaporates water from our oceans surfaces, leaving the salt behind. Rain! The planet's natural process produces, more efficiently - and without the intermediate process of boiling, much more potable water than we ever will. It'd be crazy not to use this - already processed water in favor of time consuming desalination processes. Technology that, although I'm thankful for, is hampered by the important constraints of time per unit consumption rates. Now, before I move on to the next item, consider if it should rain non-stop on our planet. *Bracketing the result of worldwide flooding (unless rainfull accumulation perfectly matches an areas consumption rate) it would be senseless to seek other water sources that require collection, extraction, shipping and conversion. No brainer.

*Unless, of course, your particular city's water table is so low such that it adversely affects yield and cost (cost incurred from expensive pumping wells, electricity to run them, maintenance, etc.)

Consider an oil or natural gas well. Most of them yield nine times as much dirty water per barrel of oil. They are called dirty wells. The filtration process is an added time consuming stage inherent in oil production. As opposed to some distant galaxy's region having produced it in vast pools of clean deposits, virtually foregoing the time consuming conversion/extraction process.

In summary, there is a consistent water shortage in Los Angeles where the water plants are sitting right on the ocean. And LA has a population under 3.5 million. The HV will have more efficient technology I suppose, but it also has... 100 billion people did you say on a colony ship??? What???

Water collected in space has to be processed. Fresh water sources groundside might not have to be processed and filtered. Mother nature has been doing that to fresh water sources for eons. Barring any toxicity from a planet, which I think is the exception and not the rule. Like Grayson.

tlb wrote:

penny wrote:I am none too sure it is realistic to expect any ship to assist any other ship that develops problems. All of the colony ships are coasting and no ship will want to slow down to assist a ship that might be falling behind. And shuttles only have so much range.

If they are coasting, then no one is going to fall behind. I think it is just the economics of one big ship over several smaller ones. Any problems would have to be fixed by the tools and machines at hand. Calvin's Hope only had the problem of fuel, but there was still enough to get them to another planet.

True, but I am considering a worst-case scenario. Colony ships should be self sufficient for them to be characterized as a colony ship. If it needs assistance from another ship then it has suffered a catastrophic disaster which may begin to cause it to lag behind, e.g., even though they are coasting these ships have to occasionally fire thrusters for course corrections. If there has been a major explosion, or there has been trouble with the thrusters, or if thruster fuel has been lost then a colony ship could wander off course.

tlb wrote:Why in space (if not on Earth) would you think that it would be easy to get hydrogen from a gas giant in the days before contra-gravity? They would expend much of the fuel just trying to escape the gravity well.

Why shouldn't it be a good example? They actually had an alternative. There is no way to plan for such a disaster, from the distance that they had to travel.

There are ways to get hydrogen from the gas giants. We don't have the technology for it yet, but we do know the physics needed. In any case, after rereading Dark Fall, it looks like Calvin's Hope could actually refuel from gas giants. What they didn't have was food, because it was a generation ship, not a cryo one:

Dark Fall, March 552 Post Diaspora wrote: “Our reserve will carry us another seventy-five years—maybe ninety, if we stretch it hard and start winding our population down pretty damned quickly—and that’s about it.” She smiled without any humor at all. “I’m sure three quarters of a century seemed like an ample safety margin to the mission planners.”
[...]
“We’ve got those seventy-five years Shirley mentioned,” he reminded them. “That’s not long enough for us to make Beowulf, or even any of our original alternative destinations like Bryant, even assuming the ship systems had that much endurance left. But we’ve got time to think and plenty of time to re-tank from the gas giants, once we get the atmospheric distillation plant deployed. So we’re not going to run out of air or power tomorrow, and the last damned thing we’re going to do is to panic or let anyone else in Calvin’s Hope panic. Is that clear?”

And

Dark Fall, March 1916 Post Diaspora wrote:How she’d crossed the almost ten light-years from her original destination to the feeble warmth of the K8v star her passengers had renamed Refuge was one of the things no one would ever know, however. Simply finding Sanctuary in Refuge’s narrow habitable zone in a system where interplanetary dust was so dense even ships with military-great particle screening dared not attain velocities much in excess of 0.5 cee must have been a monumental task—after all, no one else had found it since, although, to be fair, no one had looked all that closely with so much other, more desirable stellar real estate available to anyone with a hyper-generator. But the KCR-126-06 System had been the only haven the Calvin Expedition could possibly have reached before their vessel’s internal systems failed.

Calvin’s Hope’s specifications were readily available, given that it was one of the most famous Dutchmen in galactic history. And from those specifications, she couldn’t possibly have had more than a century or so of reserve endurance. With that limitation, she couldn’t have accelerated to her designed cruising velocity and stayed there long enough for her scoop field to replenish her reaction mass. That limited her to a maximum velocity of no more than ten percent of light-speed, if she meant to decelerate at the end of her voyage.

And KCR-126-0 6 was the only star system which lay within less than a century’s travel—at 0.1 cee—of Calvin’s Star.

(please take note of the interplanetary dust limiting speeds for the thread about the MAlign attacking Bolthole)

My argument that it was a reckless planning is because there was nowhere else they could go from the Calvin System, when they set out. They couldn't have known about the Refuge system all the way from Earth, because of that dust cloud obscuring observations. Sure, we'd know there were planets there and roughly their mass, but without a direct observation we wouldn't know if they were habitable or not, so it couldn't be in their plans.

The most important evidence that it wasn't in their plans is that no one went to look for them in Refuge. The expedition itself was well-known and there were follow-ups later to the system. If going to Refuge was part of the plan, then that would have been the first stop of the "let's find out what happened to Calvin's Hope" expedition that a lot of entities would have launched. And it doesn't match the dialogue.

penny wrote:Water collected in space has to be processed. Fresh water sources groundside might not have to be processed and filtered. Mother nature has been doing that to fresh water sources for eons. Barring any toxicity from a planet, which I think is the exception and not the rule. Like Grayson.

I'm not arguing it doesn't have to be. But please consider:

a) there is no plumbing on a wild planet, so some processing is still necessary on your new colony;

b) the problem of processing water in space will have long been solved in the Sol system by the time of the launch of the majority of those colony expeditions.

Besides, as I argued before, you will need water, food, and air in space anyway.

penny wrote:True, but I am considering a worst-case scenario. Colony ships should be self sufficient for them to be characterized as a colony ship. If it needs assistance from another ship then it has suffered a catastrophic disaster which may begin to cause it to lag behind, e.g., even though they are coasting these ships have to occasionally fire thrusters for course corrections. If there has been a major explosion, or there has been trouble with the thrusters, or if thruster fuel has been lost then a colony ship could wander off course.

That's true, an explosion could set the ship adrift from the formation. But if the other ships are still healthy, it should be easy for them to course-correct to stay in formation. Sending shuttles before they drift too far should also be within their capabilities.

In normal cruise, there should be two types of course-correction: one, to account for better accuracy towards their destination; and two, to keep formation. The former will likely happen once a decade at most, and far more frequently at the end of the journey than in the beginning. Those will likely be well-scheduled in advance, and all ships would be doing them together. If a catastrophe befell one of the ships shortly before the scheduled thrust, then all they have to do is cancel the manoeuvre and resolve the problem first.

The worst problem I can think of to make the ships drift apart too much is a misfire of those thrusters on a scheduled manoeuvre. But in that case, everyone would still be alive over there to fix the problem and bring the ship back into formation.

tlb wrote:Why in space (if not on Earth) would you think that it would be easy to get hydrogen from a gas giant in the days before contra-gravity? They would expend much of the fuel just trying to escape the gravity well.

Why shouldn't it be a good example? They actually had an alternative. There is no way to plan for such a disaster, from the distance that they had to travel.

ThinksMarkedly wrote:There are ways to get hydrogen from the gas giants. We don't have the technology for it yet, but we do know the physics needed. In any case, after rereading Dark Fall, it looks like Calvin's Hope could actually refuel from gas giants.

-- snip --

My argument that it was a reckless planning is because there was nowhere else they could go from the Calvin System, when they set out. They couldn't have known about the Refuge system all the way from Earth, because of that dust cloud obscuring observations. Sure, we'd know there were planets there and roughly their mass, but without a direct observation we wouldn't know if they were habitable or not, so it couldn't be in their plans.

Obviously I was wrong about hydrogen, I thought that they would have to get it from water (however it would become much easier once contra-gravity was available).

But still; the planet had been surveyed, so going there was no more reckless than sailing to the new world in the days of pirates and before weather knowledge. It is always "reckless" to leave certainty behind.

Should there be a problem with food on a cryo-ship? Shouldn't there be some hydroponics to feed the small fraction of people that are awake at any time? Now that does require minerals (some of which can be recycled); but wouldn't that be even easier to replenish than the hydrogen?

tlb wrote:Obviously I was wrong about hydrogen, I thought that they would have to get it from water (however it would become much easier once contra-gravity was available).

I didn't either. I hadn't remembered that detail until rereading the relevant sections.

But still; the planet had been surveyed, so going there was no more reckless than sailing to the new world in the days of pirates and before weather knowledge. It is always "reckless" to leave certainty behind.

There was no direct survey of the Calvin System. They said they had sufficiently-detailed images of it, indicating that the Sol System probably had light interferometry arrays (something that we are actually quite close to developing), possibly multiple AU-wide (something we're not). They said they had seen forests.

But all the spectrography, images, radio and other EM radiation wouldn't tell you if the planet was actually toxic or had untameable large predators. Therefore, going out there and being unable to redirect elsewhere was reckless.

Though I'll grant them one thing: maybe they hadn't been, if the 75-year surplus was meant to allow them to establish a space-borne infrastructure I've been talking about, if needed, near the time of landing. So if it was toxic, they could live in space while working to de-toxify sufficient areas (Grayson did). It's just that no one accounted for the planet being boiled over as a contingency.

And yet, we know the Calvin expedition was launched trying to get away from Sol. They didn't wait; so I do feel correct in saying they were somewhat reckless.

Should there be a problem with food on a cryo-ship? Shouldn't there be some hydroponics to feed the small fraction of people that are awake at any time? Now that does require minerals (some of which can be recycled); but wouldn't that be even easier to replenish than the hydrogen?

That was a generational ship, not cryo. So people were alive aboard all the time, keeping probably the same level of population as originally, possibly even growing along the centuries if that was the plan. The text does say that they would need to limit population (my guess is by limiting growth, not voting some people off the ship).

So it's weird that they had hydroponics to keep people alive and fed for ~400 years, but couldn't stretch that by more than 20%. It's true that no regenerative system is perfect - there are always losses - but they weren't out of power, air or water. So I agree with you, they should have been able to add minerals from the Calvin System, especially with the amount of debris that would have been around the orbit of their originally intended home. And carbon, for the organic compounds, is after all the fourth most abundant element in the universe..

ThinksMarkedly wrote:
That was a generational ship, not cryo. So people were alive aboard all the time, keeping probably the same level of population as originally, possibly even growing along the centuries if that was the plan. The text does say that they would need to limit population (my guess is by limiting growth, not voting some people off the ship).

So it's weird that they had hydroponics to keep people alive and fed for ~400 years, but couldn't stretch that by more than 20%. It's true that no regenerative system is perfect - there are always losses - but they weren't out of power, air or water. So I agree with you, they should have been able to add minerals from the Calvin System, especially with the amount of debris that would have been around the orbit of their originally intended home. And carbon, for the organic compounds, is after all the fourth most abundant element in the universe..

I reread Dark Fall, the ship was wearing out. The projection was that they - when they had discovered the scope of the damage to the planet from the two astroid hits-

“—and that’s it,” Shirley McKellen, Calvin’s Hope’s chief environmental engineer, said in a #at voice. “Our reserve will carry us another seventy-!ve years—maybe ninety, if we stretch it hard and start winding our population down pretty damned quickly—and that’s about it.” She smiled without any humor at all. “I’m sure three quarters of a century seemed like an ample safety margin to the mission planners.”

Probably not so much food, since they would have had hydroponics (except for critical trace nutrients that they may or may not have been able to recover in recycling human waste and bodies of the deceased), but parts and other equipment consumables that were wearing or for which they had no way to rebuild. The ship was "banged up" and much of it-including the fusion power plant- was was within 20 to 30 years of their design lives with no tech enough to rebuild it. That ship was 402 years old when they got to their original destination.

So there probably was no way they could expect to build some sort of orbital habitat if for no other reason than the were going to not be able to keep it running once the fusion plant stopped working. They were lucky to find the planet they did but then Murphy came to call and they were in still in the process of drawing themselves back to about the Steam Age after more than 1,000 years when the PRH survey ship showed up.