Blue Origin Thread (merged)

[ment18]

From my experience with robotics, simpler systems are almost always better.  With SXs mars architecture, they only have two main parts, one engine, and a mass over in resistant design.  By adding a bunch of extra things that have to last longer or be dead weight most of the trip, they vastly increase development costs.  Additionally two similarly sized vehicles can use similar tooling, something a smaller lander couldn't do.  Lastly, engine out capability in a lander would be nowhere near as good a the 9 engines on spaceship.

[Northstar1989]

14 hours ago, ment18 said:

From my experience with robotics, simpler systems are almost always better.  With SXs mars architecture, they only have two main parts, one engine, and a mass over in resistant design.  By adding a bunch of extra things that have to last longer or be dead weight most of the trip, they vastly increase development costs.  Additionally two similarly sized vehicles can use similar tooling, something a smaller lander couldn't do.

Higher development costs for lower long-term costs is kind of my point.  None of the ideas I suggested would pay for themselves quickly.  Landers, Cyclers, and Cargo-Crew seperation all yield a between 2 and 10% reduction in costs for increasing the R&D budget probably between 20 and 50%.

I think most people here are mistaking my fundamental point.  I think the long-term costs of SpaceX's current architecture are too high.  I don't think a Mars colony will be feasible at $140k a ton to Mars.

I think that, at that cost, it will be prohibitively expensive to send all the cargo people need to survive on Mars with them.  Musk is right, you can get a person to Mars for 1-2 tons of payload, and enough people would buy a $280k ticket to send a million people at that price.  But you *NEED* at least 8-10 tons or so of cargo on the Martian surface in ADDITION to that to survive long-term, otherwise all you get is a "flag-and-footprints" mission.  And too few people would be both able and willing to buy a $1.4 million ticket.

Starting with that fundamental criticism, and then saying "what can Musk do to fix it" is the basic jist of my entire arguments...  I think SpaceX needs to draw up an even lower-cost plan than what they have now, and then take as long as necessary to fund its R&D out of existing operating profits if capital costs from borrowing the money would drive up costs too much...

 

Regards,

Northstar

Edited October 10, 2016 by Northstar1989

[kerbiloid]

15 hours ago, ment18 said:

From my experience with robotics, simpler systems are almost always better.  

"Make things as simple as possible, but not simpler. " (c) A.Einstein

A train with carriages welded together is more simple than a usual one, but unlikely could be used. It requires at least 6 degrees of freedom.

The same with Apollo scheme vs Direct Ascent.

 

42 engines + 42 pumps + 84 pipelines = simple? Ok...

Edited October 10, 2016 by kerbiloid

[shynung]

@Northstar1989 Your mission architecture involving dedicated landers, cycler habs, and cargo-crew separation is more appropriate when there are permanent settlements on Mars that require a continuous logistics train. Right now, Musk's colonists is going there as pioneers, which means there are no infrastructure waiting there to support them. That's why Musk aims for a simple, reliable vehicle to get them there; it's more akin to settler wagons, as when one fails, sending another one is as easy as building/preparing a duplicate vehicle and finding another group of colonists.

Don't get me wrong, losing a whole ship of Mars colonists would still be a disaster. But it's easier to plan another mission when there's only one vehicle type to be concerned with, rather than an entire cycler-lander-cargoship fleet to deal with.

 

21 minutes ago, kerbiloid said:

"Make things as simple as possible, but not simpler. " (c) A.Einstein

A train with carriages welded together is more simple than a usual one, but unlikely could be used. It requires at least 6 degrees of freedom.

The same with Apollo scheme vs Direct Ascent.

 

42 engines + 42 pumps + 84 pipelines = simple? Ok...

The idea is that the engines+pumps (in a rocket engine, the combustion chamber, nozzle, and turbopump are designed as a single unit) are identical, so the vehicle can reap the benefits of mass production. Plus, having many engines add redundancy, so the vehicle can withstand multiple engine loss events. Pipelines are just a bunch of pipes; the biggest expense on them would be planning the pipe routing, and that'll be done only once or twice.

[Blaarkies]

4 minutes ago, shynung said:

The idea is that the engines+pumps (in a rocket engine, the combustion chamber, nozzle, and turbopump are designed as a single unit) are identical, so the vehicle can reap the benefits of mass production. Plus, having many engines add redundancy, so the vehicle can withstand multiple engine loss events. Pipelines are just a bunch of pipes; the biggest expense on them would be planning the pipe routing, and that'll be done only once or twice.

Everyone fears that it sounds very similar to the N1. Back then, if one engine gently exploded, the others followed suit. IIRC, the superdraco engine are "contained" so that an engine explosion doesn't damage an adjacent engine? If they can do the same with the Raptors, then they are definitely safer than anything we are currently using

[shynung]

6 minutes ago, Blaarkies said:

Everyone fears that it sounds very similar to the N1. Back then, if one engine gently exploded, the others followed suit. IIRC, the superdraco engine are "contained" so that an engine explosion doesn't damage an adjacent engine? If they can do the same with the Raptors, then they are definitely safer than anything we are currently using

I like to think that SX engineers have higher standards than their Soviet equivalents. They did 9 engines on one stage successfully. Then again, 42 is a lot, so we'll see.

BTW, N1 was plagued by a lot of problems unrelated to its engine cluster design. I read somewhere in Wikipedia that the 3rd launch failed because a stray bolt got into the turbopump.

[kerbiloid]

1 hour ago, shynung said:

Pipelines are just a bunch of pipes;

And (84 * N) joints. With possible cracks.
And ( 84 * M) valve(s). With possible leaks.

1 hour ago, shynung said:

the biggest expense on them would be planning the pipe routing,

And pipelines mass. A big pipe usually weights less than several small ones.

 

As a book tells, 53 Shuttle main engines were built, each with estimated lifespan 27000 seconds or 55 flights and estimated probabily of failure 1:1283 (data of year 2000).
As wiki tells, 47 were built, 46 spent, 7 failures happened in flight, failure possibilty 0.05% = 1:2000.

0.9992⁴² .. 0.9995⁴² = 0.967..0.980, I.e. 2..3% chance of an engine failure during a flight - if every engine will be cared as RS-25 between flights.

But 46 spent Shuttle engines per 5 ships and 135 flights mean than in average, a Shuttle engine made 135 * 3 / 46 = 8.8 flights, being considered as still reliable. (8.8 of 55 by default)
From this pov, the expectancy of engines number to be replaced after any flight = 42 / 8.8 = 4.8.
I.e. if after every ITS flight they will disassemble the rocket (as they did with Shuttle), they should replace ~5 engines as damaged enough to get out of service.
If not (as in the animation) - a failure probability would only increase.

Edited October 10, 2016 by kerbiloid

[shynung]

1 hour ago, kerbiloid said:

And (84 * N) joints. With possible cracks.
And ( 84 * M) valve(s). With possible leaks.

Properly engineered, what's the chance of a joint or valve failing before the turbopump? I'd bet that they'll last longer than the engines unless underengineered to a significant degree.

1 hour ago, kerbiloid said:

And pipelines mass. A big pipe usually weights less than several small ones.

That decreases redundancy and reliability; if a big pipe supplying several engines leaked or failed, that would affect all the engines feeding off that pipe. Providing each engine with its own fuel delivery system would ensure isolating a problematic pipe's effects to the engine it supplies.

Yes, it's heavy. But for a pioneer lander needing ultra-reliable hardware, I think we can spare some more mass on redundancy.

1 hour ago, kerbiloid said:

As a book tells, 53 Shuttle main engines were built, each with estimated lifespan 27000 seconds or 55 flights and estimated probabily of failure 1:1283 (data of year 2000).

As wiki tells, 47 were built, 46 spent, 7 failures happened in flight, failure possibilty 0.05% = 1:2000.

0.9992⁴² .. 0.9995⁴² = 0.967..0.980, I.e. 2..3% chance of an engine failure during a flight - if every engine will be cared as RS-25 between flights.

But 46 spent Shuttle engines per 5 ships and 135 flights mean than in average, a Shuttle engine made 135 * 3 / 46 = 8.8 flights, being considered as still reliable. (8.8 of 55 by default)
From this pov, the expectancy of engines number to be replaced after any flight = 42 / 8.8 = 4.8.
I.e. if after every ITS flight they will disassemble the rocket (as they did with Shuttle), they should replace ~5 engines as damaged enough to get out of service.

Looks reasonable to me. The reason SX used many engines in one stage is to reap the benefits of mass production, so that the cost of each individual engine is manageable. I believe replacing a few engines after each flight would trouble the flight plan rather lightly, unless ITS wasn't planned to have its engines individually replaced; if so, why bother with reusability if the rocket stage is junked every time one engine out of 42 quits?

Edited October 10, 2016 by shynung

[DerekL1963]

26 minutes ago, shynung said:

The reason SX used many engines in one stage is to reap the benefits of mass production

Partly.  But also because the Falcon I was a dead end (the expected market never materialized) and using five and then nine of an existing design was faster and cheaper to market than starting over.  Even then, it was a close race - at one point Musk was within hours of having to decide whether to throw Tesla or SpaceX overboard to give the other a chance of surviving...  then the ISS resupply contracts came through.

That being said, none of the N-1's problem's were directly connected with having that many engines.  The main problem was getting KORD (the engine control system) functioning properly.  Had they ever actually performed static testing on the Block A stage, they might have worked out the bugs.

[Streetwind]

Okay, time to catch up with this thread... not gonna touch the, erm, 'spirited discussion' among the usual suspects with a ten-foot pole, but here's a few snippets I felt worthy of remarks:

 

On 7.10.2016 at 1:44 PM, Technical Ben said:

Bare in mind. Elon is not planning on sending anyone back. So a single shot lander for Mars only is the way they are going. The re-use lander would only work if done with a cycler system, giving a re-use lander for Mars only. We are not going to be returning that to earth.

Shocked that nobody has corrected this in several days. The whole point of the SpaceX ITS infrastructure is that it is reusable. The entire spacecraft is taking back off and coming back home. And anyone who wants to can fly home along with it. No cycler required.

This isn't news either. Elon Musk has talked about this for about three years now, and reiterated it multiple times during the reveal at IAC.

 

On 8.10.2016 at 6:46 AM, Northstar1989 said:

He hasn't even *begun* to challenge the seriously difficult problem of safe orbital refueling, as far as anyone knows.

Objection! Safe orbital refueling is a solved problem. We've been doing it for over a decade, using poisonous hypergolics on human-rated spacecraft (example: ISS). Admittedly we haven't done much with cryogenic fuels. But that's just a plumbing engineering problem, not fundamentally new stuff, since the behavior of cryogenic liquids in microgravity is well known (can be observed on almost every rocket launch, including SpaceX's own). And ITS uses only "soft" cryogenics in the first place.

 

On 9.10.2016 at 3:11 AM, Northstar1989 said:

It sounded like a pie-in-the-sky idea to me when I read about it (way more than, say, dedicated landers- which are really just an extension of the concept used in Apollo).  Do you think it has any serious chance of actually working?

The thing about MSNW's fusion rocket is that it's not a fusion reactor. The thing that holds up fusion research worldwide is creating a sustained fusion reaction with an output energy that exceeds the input energy, as well as actually harvesting that output energy. Both of these are extremely difficult problems that have no clear solution right now. And both of these things can be flat-out ignored by MSNW. They just need to ignite an instantaneous fusion pulse, repeatedly. And they don't need to jump through hoops to harvest the energy either: they just let the thing go off inside a magnetic nozzle, so the whole pulse gets directed out back and pushes the spacecraft forwards. It's really more like a much more practicable mini-Orion drive than it is some sort of sci-fi fusion thruster.

So even though it comes with the "fusion" moniker, it actually avoids the majority of technical issues that plague fusion research. As such, it has a decent chance of being practicable in the near future.

(And do note: this isn't an all-purpose engine. It's an in-space-only, high Isp, low thrust, solar electric engine. It won't take off from anywhere, it won't land anywhere, and it won't compete with chemical engines. It will compete with ion and plasma thrusters on large scales, which it hopes to beat in thrust output, versatility and system mass while having comparable Isp.)

Edited October 10, 2016 by Streetwind

[Kryten]

5 hours ago, Blaarkies said:

Everyone fears that it sounds very similar to the N1. Back then, if one engine gently exploded, the others followed suit. IIRC, the superdraco engine are "contained" so that an engine explosion doesn't damage an adjacent engine? If they can do the same with the Raptors, then they are definitely safer than anything we are currently using

We're talking engines with the highest chamber pressure ever, on a vehicle which has to achieve one of the highest mass fractions ever. Containment would be extremely difficult.

[Nefrums]

The  MSNW  is closer to a micro fusion bomb than to a fusion reactor.

It will use magnetic fields to comperes the deuterium to ignite fusion just like in a fusion reactor, (a H-bomb uses a fission bomb to ignite fusion). The hard part with using magnetic fields is to sustain them, this requires large superconductors etc.  This will not be done in the MSNW, the magnetic fields will not be sustained and fussion will only happen in very short pulses.

The energy required to ignite fusion would be huge.  And the thermal losses in the electromagnets would be large.  So even a short (ms) pulse would require some time afterwards to let the engine cool down and the capacitors to be recharged by the solar panels.

Still, if they can get it to work it would be like a ion engine with several order of magnitude better thrust and thrust/W.

[kerbiloid]

4 hours ago, DerekL1963 said:

That being said, none of the N-1's problem's were directly connected with having that many engines.  The main problem was getting KORD (the engine control system) functioning properly

3 of 4 failures were caused by an engine or turbopump mechanical destruction, 1 of 4 - insufficient vernier engine force.
None of them are caused by Kord.  Kord just failed to keep the damaged rocket flying.

(Sorry, in Russian)
https://ru.wikipedia.org/wiki/Н-1#.D0.9F.D1.83.D1.81.D0.BA.D0.B8

2 hours ago, Streetwind said:

Safe orbital refueling is a solved problem

2 tons per flight, non-cryogenic hypergolics?

Edited October 10, 2016 by kerbiloid

[Streetwind]

16 minutes ago, kerbiloid said:

2 tons per flight?

The amount carried by the tanker does not fundamentally change anything about a known process. It's a plumbing engineering issue, nothing more.

The bigger issue here is getting the fuel systems of the spacecraft as a whole to work the way they want. In my (admittedly amateurish) opinion, the act of moving liquids between two spacecraft is a mere footnote to the challenges of designing a cryogenics-capable, actively refrigerated carbon-composite tank that survives ten years of repeated filling and emptying in three different environmental conditions... and on that absurd scale, no less! I think it's quite indicative that SpaceX has decided to get a head start on exactly that.

Edited October 10, 2016 by Streetwind

[kerbiloid]

14 minutes ago, Streetwind said:

The amount carried by the tanker does not fundamentally change anything about a known process.

It changes the craft balance, can cause oscillations, rotations and break some link or pipe.
If the tank is large, in zero-G it may (or may not) be as a lava lamp with clots of liquids (each several tons), floating, splitting and rejoining, pushing the tank unpredictably.
If the fuel is cryogenic, it's enough hard to compensate the evaporation losses (as you dont have oxygen factory on orbit), while any vent becomes a mini rocket nozzle.

Upd:
It's a small LOx tank of Buran designed to store it for 2-3 weeks (with a skimmer).

Spoiler

 

Edited October 10, 2016 by kerbiloid

[Northstar1989]

9 hours ago, shynung said:

@Northstar1989 Your mission architecture involving dedicated landers, cycler habs, and cargo-crew separation is more appropriate when there are permanent settlements on Mars that require a continuous logistics train. Right now, Musk's colonists is going there as pioneers, which means there are no infrastructure waiting there to support them. That's why Musk aims for a simple, reliable vehicle to get them there; it's more akin to settler wagons, as when one fails, sending another one is as easy as building/preparing a duplicate vehicle and finding another group of colonists.

Don't get me wrong, losing a whole ship of Mars colonists would still be a disaster. But it's easier to plan another mission when there's only one vehicle type to be concerned with, rather than an entire cycler-lander-cargoship fleet to deal with.

 

The idea is that the engines+pumps (in a rocket engine, the combustion chamber, nozzle, and turbopump are designed as a single unit) are identical, so the vehicle can reap the benefits of mass production. Plus, having many engines add redundancy, so the vehicle can withstand multiple engine loss events. Pipelines are just a bunch of pipes; the biggest expense on them would be planning the pipe routing, and that'll be done only once or twice.

I don't know- with that many pipes there are an awful lot of places for something to go wrong...  I'm REALLY starting to think Elon should downsize the ITS a bit.  Maybe to 36 engines or 32?  And downsize the payload accordingly.  Same principle as the landers- the larger your rocket, the more "eggs" you place in one basket and the riskier your entire scheme.  32 engines should still provide engine-out capability...

As for the need for continuous logistics, may I remind everyone that for the first 1-2 decades, the budding Mars colony WON'T be self-sufficient.  But it will *certainly* be permanent from the time the first crewed rockets arrive, because the ITS only has the capacity to take about 20 crew back each transfer window...

That means the colony will need resupply every 2 years.  And it might very well need more crew-return capacity than the ITS's bringing more crew can provide.  In THAT context, landers and cyclers start to look drastically more appealing as they both dramatically increase crew-return capability, by cutting down on the Delta-V the ITS needs to expend to return to Earth... (3.8 km/s less with landers, NONE with a Cycler)  And a cargo-only ITS is one easy way to meet the need for biannual supply runs to the colony until it becomes self-sufficient.

 

7 hours ago, shynung said:

Properly engineered, what's the chance of a joint or valve failing before the turbopump? I'd bet that they'll last longer than the engines unless underengineered to a significant degree.

That decreases redundancy and reliability; if a big pipe supplying several engines leaked or failed, that would affect all the engines feeding off that pipe. Providing each engine with its own fuel delivery system would ensure isolating a problematic pipe's effects to the engine it supplies.

Yes, it's heavy. But for a pioneer lander needing ultra-reliable hardware, I think we can spare some more mass on redundancy.

Looks reasonable to me. The reason SX used many engines in one stage is to reap the benefits of mass production, so that the cost of each individual engine is manageable. I believe replacing a few engines after each flight would trouble the flight plan rather lightly, unless ITS wasn't planned to have its engines individually replaced; if so, why bother with reusability if the rocket stage is junked every time one engine out of 42 quits?

Properly engineered, the chance of a joint or valve failing is actually pretty high.  In fact, if my memory serves correctly, valve-failures have been the cause of *several* launch failures over the years...  I'd bet that not all of those were due to poor engineering- sometimes parts simply fail...

Plus, you couldn't supply each engine from a different pipe leading off the fuel tank- you'd get all sorts of weird vortexes and other issues with the fuel flow.  The way you supply that many engines at once is that each tank has a single large pipe leading off it, which then branches off into many smaller pipes.

Much like the design of the human heart, where, not coincidentally, all the blood in the body, after returning from the lungs via the pulmonary veins (the human body essentially has two circulatoru systems in series- one to the lungs, one to the rest of the body after the blood is oxygenated.  The two are divided by a VERY thick and strong wall between the halves of the heart, and if they EVER interconnect you get MAJOR issues...) exits the heart through a single vessel- the Aorta.

This is DESPITE major risks this poses to the survival of the organism from the Aorta bursting (which happens surprisingly often- especially following traumatic injury or with certain genetic defects).  Similarly, having that much fuel exiting the ITS tanks through a single large pipe and branching into smaller pipes puts a lot of stress on the valve and junctions of that large pipe- and if it fails, it's game-over for the rocket...

 

Regards,

Northstar

Edited October 10, 2016 by Northstar1989

[shynung]

43 minutes ago, Northstar1989 said:

As for the need for continuous logistics, may I remind everyone that for the first 1-2 decades, the budding Mars colony WON'T be self-sufficient.  But it will *certainly* be permanent from the time the first crewed rockets arrive, because the ITS only has the capacity to take about 20 crew back each transfer window...

That means the colony will need resupply every 2 years.  And it might very well need more crew-return capacity than the ITS's bringing more crew can provide.  In THAT context, landers and cyclers start to look drastically more appealing as they both dramatically increase crew-return capability, by cutting down on the Delta-V the ITS needs to expend to return to Earth... (3.8 km/s less with landers, NONE with a Cycler)  And a cargo-only ITS is one easy way to meet the need for biannual supply runs to the colony until it becomes self-sufficient.

What you're proposing would be akin to building a railway network to a town that doesn't even exist yet in order to settle people there. Musk's plan would be similar to sending settler wagons to the same location to do the same job.

Now, if Mars have enough people there to be considered something more than a scientific outpost (like what we have in the south pole), then building an interplanetary logistical 'railroad' of cyclers, shuttles, stations, and landers, where the needs for efficiency outweighs flexibility starts to sound like a good idea. Until that point, I think we should send the space equivalent of settler wagons that are more flexible in order to be prepared for anything the Kraken throws at us.

Edited October 10, 2016 by shynung

[magnemoe]

2 hours ago, kerbiloid said:

It changes the craft balance, can cause oscillations, rotations and break some link or pipe.
If the tank is large, in zero-G it may (or may not) be as a lava lamp with clots of liquids (each several tons), floating, splitting and rejoining, pushing the tank unpredictably.
If the fuel is cryogenic, it's enough hard to compensate the evaporation losses (as you dont have oxygen factory on orbit), while any vent becomes a mini rocket nozzle.

Upd:
It's a small LOx tank of Buran designed to store it for 2-3 weeks (with a skimmer).

  Hide contents

 

You can store LOX and methane in space using just an shadow shield if you get no heating from the rest of the craft, an helium cooling loop with an radiator on shadow side help. Hydrogen require active cooling. 
Not sure about the mars ship as it has the tanks sandwiched between cargo hold and engines. it would be an challenge to keep cool. 
You would need active cooling on Mars but here it would be easier to get rid of heat. 

 

 

[Northstar1989]

20 minutes ago, shynung said:

What you're proposing would be akin to building a railway network to a town that doesn't even exist yet in order to settle people there.

Funny you should say that, because that's *EXACTLY* what the railway companies used to do, and how a lot of towns and cities in the American West came into existence...

They built railways to potential town sites because rail was the only economical way of servicing towns with goods and cargo- the towns could have never sprung into existence without the railroad, and the railroad had no customers without the town.  It was a mutually-beneficial relationship.

Similarly, a Mars colony will never get off the ground in (figuratively speaking) if the only way we have of bringing it cargo is sending a giant crewed vehicle on an 8 km/s Mars transfer, and the only way we have of bringing people back is to send such a rocket all the way to Mars and only bringing 20% as many people back by the same ridiculously expensive (fuel-wise and literally) trajectory.

We need a cheaper way of getting cargo there- something that takes a nice, slow, 180-day trajectory to Mars, and is fully-reusable.  An unmanned ITS stuffed to the brim with cargo is just one option, and possibly not even the best such option.  Something smaller you could launch on a Falcon Heavy would probably be more economical in the long run, even though it would require the development of a seperate Mars transfer-stage and landing system.  Moderate sized craft are generally cheaper and easier to design than behemoths like the ITS, fortunately.

As for returning crew more economically, Cyclers and Landers are two seperate, *competing* solutions (stop saying one requires the other- just the opposite, they each make the other less useful...)  A Cycler launched specifically to return crew to Earth would be faster and cheaper in itself, as it would basically just be an ITS on a different trajectory- but a Lander architecture would allow you to carry more crew *to* Mars on each trip as well as proportionally more back from it (Cyclers on return-voyage trajectories aren't practical for getting to Mars quickly in the first place, taking 21 months, just as Mars-bound Cyclers don't return to Earth for 21 additional months after passing Mars...)

20 minutes ago, shynung said:

What you're proposing would be akin to building a railway network to a town that doesn't even exist yet in order to settle people there. Musk's plan would be similar to sending offroad trucks to the same location to do the same job.

Now, if Mars have enough people there to be considered something more than a scientific outpost (like what we have in the south pole), then building an interplanetary logistical 'railroad' of cyclers, shuttles, stations, and landers, where the needs for efficiency outweighs flexibility starts to sound like a good idea. Until that point, I think we should send the space equivalent of settler wagons that are more flexible in order to be prepared for anything the Kraken throws at us.

 

Edited October 10, 2016 by Northstar1989

[kerbiloid]

5 minutes ago, magnemoe said:

You can store LOX and methane in space using just an shadow shield if you get no heating from the rest of the craft, an helium cooling loop with an radiator on shadow side help. Hydrogen require active cooling. 

And it masses?...

And anybody already did that?

And active cooling system requires a powerplant, which produces additional waste heat, which both has mass and heats the ship, including tanks.

[shynung]

22 minutes ago, Northstar1989 said:

Funny you should say that, because that's EXACTLY what the railway companies used to do, and how a lot of towns and cities in the American West came into existence...

They don't. In its early history, US railroad companies focused on connecting industrial sources (mostly mines) to their respective processing plants, then later transporting people between large cities. When steam engines first arrived at the scene, they were small locomotives than can carry a limited amount of water and fuel. At predetermined locations (water/fuel stops), the trains would stop for a while, refilling their water and fuel supplies, and then continue on their journey. It is these refilling stops that later become railroad towns, whose residents thrive from the existence of the refilling stop itself, taking job opportunities offered by the railway company to run the refilling stop, as well as being a local transportation (hence, trading) hub.

The railroad companies themselves have no interest in building a rail line to the middle of nowhere, with no resources nearby worthy picking up and transporting elsewhere, just to start a town there. It would generate no profit. Railroad towns grew because people see opportunities in servicing trains stopping in a refilling stop, enough so that some people willingly build houses nearby to keep themselves available to the next train using the stop.

EDIT:

@Northstar1989 You might want to start a new thread on your approach to Mars colonization. Your continued... support... to your ideal method of colonization is starting to derail this thread.

Edited October 10, 2016 by shynung

[magnemoe]

7 minutes ago, kerbiloid said:

And it masses?...

And anybody already did that?

And active cooling system requires a powerplant, which produces additional waste heat, which both has mass and heats the ship, including tanks.

Space is cold, if you insulate the tank from the sunlight and heat from rest of the ship LOX would stay liquid. 

Nobody has used methane before, you could do it with LOX and RP1, but this would complicate stuff and make it more bulky.
Not sure how easy it would be to do inside the mars transport hull as i said. 

[Northstar1989]

12 minutes ago, shynung said:

They don't. In its early history, US railroad companies focused on connecting industrial sources (mostly mines) to their respective processing plants, then later transporting people between large cities. When steam engines first arrived at the scene, they were small locomotives than can carry a limited amount of water and fuel. At predetermined locations (water/fuel stops), the trains would stop for a while, refilling their water and fuel supplies, and then continue on their journey. It is these refilling stops that later become railroad towns, whose residents thrive from the existence of the refilling stop itself, taking job opportunities offered by the railway company to run the refilling stop, as well as being a local transportation (hence, trading) hub.

The railroad companies themselves have no interest in building a rail line to the middle of nowhere, with no resources nearby worthy picking up and transporting elsewhere, just to start a town there. It would generate no profit. Railroad towns grew because people see opportunities in servicing trains stopping in a refilling stop, enough so that some people willingly build houses nearby to keep themselves available to the next train using the stop.

That's simply not accurate.  Yes, sometimes towns grew up around refueling stops- but railroads often also built spurs to the middle of nowhere (technically to tiny farming hamlets) in the American West because they knew that towns would grow up around the stops.  The towns had natural resources (farmland, metals, etc.), they just hadn't been developed yet.  And ultimately, just like with Mars, passengers were the most lucrative, sometimes the only profitable cargo from these small towns (where it simply wasn't worth the loading-time to pick up the small amounts of freight they generated).

You're obfusticating the facts partly by confusing the timelines.  You're talking about patterns in the very early days of railroads, almost entirely on the already-developed East Coast and to a lesser extent in more developed parts of the Midwest.  I'm talking about what happened in the frontier of the American West, decades later.

 

Regards,

Northstar

Edited October 10, 2016 by Northstar1989

[shynung]

5 minutes ago, Northstar1989 said:

Yes, sometimes towns grew up around refueling stops- but railroads often also built spurs to the middle of nowhere (technically to tiny farming hamlets) because they knew that towns would grow up around the stops.  The towns had natural resources (farmland, metals, etc.), they just hadn't been developed yet.  And ultimately, just like with Mars, passengers were the most lucrative, sometimes the only profitable cargo from these small towns (where it simply wasn't worth the loading-time to pick up the small amounts of freight they generated).

That's because the railroad company knew ahead of time that there is actually something worth carrying elsewhere. Farms, mines, forests, oil wells, etc. Mars has none of that - hell, it doesn't even have breathable air!

Think of it like this way: Mars is a far-away place that takes a considerable effort to reach physically, yet doesn't have anything we can't easily acquire here. Even if it is possible, why would anyone spent fortunes building a railroad there?

Edited October 10, 2016 by shynung

[Northstar1989]

15 minutes ago, shynung said:

That's because the railroad company knew ahead of time that there is actually something worth carrying elsewhere. Farms, mines, forests, oil wells, etc. Mars has none of that - hell, it doesn't even have breathable air!

Think of it like this way: Mars is a far-away place that takes a considerable effort to reach physically, yet doesn't have anything we can't easily acquire here. Even if it is possible, why would anyone spent fortunes building a railroad there?

Mars is a destination for passengers.  People will move there in ever greater numbers if there is a colony, and return in large numbers as well.  Like I said before (once again, you are ignoring the most important and relevant points in my post in favor of attacking auxiliary points out-of-context), people often were the only profitable cargo.

Cargo transport *to* Mars would also be in major demand, however- and due to the unique requirements of manned space travel (fast journey, low g's, crew accomodations, radiation protection, etc.) should actually be more profitable than sending the actual colonists that create a demand for it in the first place.  The fledgling colony will need food, medical supplies, electronics, construction materials hard to obtain without a developed industrial base, and countless other things.  Things which can all be shipped seperately, and on a much slower and therefore cheaper trajectory than passengers.

I shouldn't even have to explain that the colonists eould pay to have these things shipped to them rather than die alone on a lonely planet.  But only if they could afford it out of whatever savings they had left on Earth.  So the initial cost of getting the colonists to Mars in the first place needs to be low enough that the colonists have some savings left- otherwise they all die.

THIS is why the ITS plan, as it currently stands, is inadequate.  Not because people won't be able to afford the ticket, but because they won't ALSO be able to afford to have the things they need to survive the early years shipped to/with them as well.

 

Regards,

Northstar

Edited October 10, 2016 by Northstar1989