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I think they will leave most Starships on the Mars surface in the early stages. That's clearly the implication because Space X are planning only enough propellant production for one Starship to return.
Cost is not that important for these first few missions. It's all about establishing a viable base that people can live in safely and securely.
Once the base is up and running, and you have a mature energy system, a raw material stock, plenty of 3D printers, materials processing equipment, computer controlled lathes, industrial robots, recycling units and manufacturing machines etc located on Mars, then Space X can focus on moving people and habs to Mars.
With Mars ISRU underway, things might settle down for missions 3-10 with regular 2 Starship visits every launch window with both Starships returning each time. These Starships could be bringing 50 plus people each time with science experiments, exploration rovers, habs and the like, plus food supplies of course).
The PV solution doesn't really need huge tonnages of batteries. Maybe 30 tons max, given there will already be battery storage built into the architecture of the Starships (e.g. for fin actuation). Even that 30 ton figure is probably an overestimate but it's not a bad idea to overplan for Mission One.
The chances of the emergency methox store being used are also v. slim. But if you do need to replenish it, you'll be taking about 0.3% of the total (ie need to increase your production of methane and oxygen by about 0.3%).
The propellant plant facility does not have to operate at 100% capacity all the time. It might need some throughput to prevent issues arising...that may be the case. The PV approach would be different - you would have a larger propellant plant to cope with peak PV power .
A part of the problem here with propellant facility size and production rates is the disparity between what Spacex proposes as a Mars vehicle and what everybody else has proposed. The others require a few dozen to a few hundred tons at most; Spacex's vehicle will require something in the 1000-1500 ton class, for each and every vehicle that returns. And return they must to be reusable, and hold the price down, so don't kid yourself about leaving the first few dozen one-way on Mars.
Another part of the problem has to do with whether the production process works adequately as an intermittent process, or whether it is better operated continuously, around the clock. If the process works better continuously, then a solar-powered plant must have huge batteries not just to get through the night, but also the early morning and late afternoon hours, when sun angles are adverse. The only way around that dilemma is the tracking collector, a much heavier, more expensive, and difficult-to-maintain item in dusty conditions.
The alternative to solar with huge batteries is currently nuclear power. It is one thing to propose a methlox electric generator set, it is quite another to propose something like that to power your plant, even for a short time. The second law of thermodynamics says the propellant you consume making electricity is way to hell and gone far larger than the quantity your plant can make, while the generator is running.
One thing I remember from thermo class is this: "first law says you cannot win, second law says you cannot come close to breaking even, third law says not only can you not get out of the game, but also that you are gonna lose really big-time". Crudely put, but accurate.
What makes chemically-fueled combustion engines in the least feasible on Earth is the presence of a substantially-oxygenated atmosphere available "for free" and at a significant pressure. The fuel is quite the minority of the total propellant feed to the engine, usually at most around 6.5%, sometimes less as with diesel and gas turbine. 95.5+% of your propellant is free, with sufficient dilution of the oxygen to limit flame temperatures to survivable values, and at sufficiently-high inlet pressure to enable a positive return from the thermodynamic operating cycle.
Mars has neither the freely-available and properly-diluted oxygen, nor an adequate inlet pressure level. Even if it had a 21% oxygen atmosphere, at 6 mbar pressure, the giant inlet turbocharger you must have to function at all, would draw far more power than the engine could ever produce. I think you can pretty well discard the notion of "airbreathing engines" on Mars, because of those two lacks.
Not much else is known besides solar and nuclear that would work on Mars. Solar has best output between about 10 AM and 2 PM solar hour angle time, reduced output between dawn and 10 AM, and between 2 PM and sunset, and no output at all at night. Hence the need for a really big set of batteries to get you through about say 14-16 hours of the 24 more-or-less hour cycle, on Earth or Mars. And we already know its output is sharply reduced during big dust storms, even at midday. It can be essentially zero in the worst ones, which can last for days, weeks, even months.
Nuclear on the other hand, is continuous and constant 24/7 regardless. All you need is redundant power units, in case something bad happens to one of them. Mars is NOT the place to be putting all your eggs in one basket, with regard to electricity, or anything else. Too hostile to our kind of life.
And that is why I say use nuclear for the base load of propellant plant operation and night-time life support, with solar adding daytime recharge for the rechargeable battery-powered vehicles and equipment we are going to need. Use it to the max when its max is available, and you don't need such massive battery installations. That's just plain old common sense talking.
GW
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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I think they will leave most Starships on the Mars surface in the early stages. That's clearly the implication because Space X are planning only enough propellant production for one Starship to return.
Thats the one issue with going with such a large ship with no ground support build up to allow for the generation of reserves to easy the situation of a ship possibly never returning home. The second part of that is the continual 2 ship cargo that makes that matter more server in that crowding of the landing site will occur which raises the risk level.
The eventual commerce of mars with eventually ship items in the ships if they are kept in working order but how long will it take to get to that point that we are shipping more than people home.
With the possibility to land at new sites sooner rather than waiting for the massive build up the other chance to gain larger portions of mars to explore.
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How far apart the ships should be is an interesting question. Of course we saw the stunning twin landing of the two Falcon 9 H outside stages. So if all goes well, there's no problem. But, yes, why create risk? I guess a lot will depend on the nature of the landing sites. I get the impression from Mars that there aren't many areas that are flat rock with few boulders, so landing space might be at a premium. If you could choose I'd say have them at least 500 m. apart in grid fashion but with the human passenger ship even more solitary.
Louis wrote:I think they will leave most Starships on the Mars surface in the early stages. That's clearly the implication because Space X are planning only enough propellant production for one Starship to return.
Thats the one issue with going with such a large ship with no ground support build up to allow for the generation of reserves to easy the situation of a ship possibly never returning home. The second part of that is the continual 2 ship cargo that makes that matter more server in that crowding of the landing site will occur which raises the risk level.
The eventual commerce of mars with eventually ship items in the ships if they are kept in working order but how long will it take to get to that point that we are shipping more than people home.
With the possibility to land at new sites sooner rather than waiting for the massive build up the other chance to gain larger portions of mars to explore.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Back to working on the plant to produce fuel on mars has a company here on earth to do a bit of comparison to in Swiss company Climeworks. Where back a bit ago I ran the co2 levels for earth in a m^3 to that of Mars and they were almost exact to what we would be working with for input into the fuel creation process.
https://arstechnica.com/science/2018/10 … ing-plant/
The air inlets are large as a result of how much air must go in to collect the co2 content that is in our air and while mars has the higher content its the lower pressure that is the issue that forces multiple smaller inlets to do the same function on mars. The remaining plant shows just how large we will need to be for mars insitu processing to methane.
https://www.theguardian.com/sustainable … osynthesis
https://news.slashdot.org/story/18/10/0 … cing-plant
The plant consists of three air collectors that are more energy efficient than Climeworks' first ambient air collector. "The plant will filter up to 150 tons of CO2 from ambient air per year," Climeworks said in a press statement. "Simultaneously, an alkaline electrolyser (1.2 MW) locally generates 240 cubic meters of renewable hydrogen per hour by making use of excess on-site photovoltaic energy." A catalyst then combines the CO2 and the hydrogen into methane gas in a reactor built by a French company called Atmostat. The methane "is then liquified and used to fuel natural gas lorries," Climeworks says.
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One article says 150 tons a year, another says 900 tons a year. 150 tons looked low to me on the basis of the size of the intakes as, at 8 hours a day, it would only be 1.3 grams a second.
As part of his analysis of propellant production requirements on Reddit, Blake on Reddit referenced this paper as his justificaton of allocating 3 tons for atmospheric extraction (to produce enough propellant for one Starship to return to Earth).
http://www.niac.usra.edu/files/studies/ … ngland.pdf
https://www.reddit.com/r/spacex/comment … ant_plant/
Maybe Climeworks is looking for a solution that works in relation to Earth economics - that constraint doesn't apply on Mars where we can "splash the cash" for Mission One. If it costs another $100 million here or there, that's of no consequence.
Back to working on the plant to produce fuel on mars has a company here on earth to do a bit of comparison to in Swiss company Climeworks. Where back a bit ago I ran the co2 levels for earth in a m^3 to that of Mars and they were almost exact to what we would be working with for input into the fuel creation process.
https://arstechnica.com/science/2018/10 … ing-plant/
The air inlets are large as a result of how much air must go in to collect the co2 content that is in our air and while mars has the higher content its the lower pressure that is the issue that forces multiple smaller inlets to do the same function on mars. The remaining plant shows just how large we will need to be for mars insitu processing to methane.
https://www.theguardian.com/sustainable … osynthesis
https://news.slashdot.org/story/18/10/0 … cing-plant
The plant consists of three air collectors that are more energy efficient than Climeworks' first ambient air collector. "The plant will filter up to 150 tons of CO2 from ambient air per year," Climeworks said in a press statement. "Simultaneously, an alkaline electrolyser (1.2 MW) locally generates 240 cubic meters of renewable hydrogen per hour by making use of excess on-site photovoltaic energy." A catalyst then combines the CO2 and the hydrogen into methane gas in a reactor built by a French company called Atmostat. The methane "is then liquified and used to fuel natural gas lorries," Climeworks says.
Last edited by louis (2019-10-22 04:10:41)
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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For Louis and SpaceNut re #29 and #30
The discussion you are holding here contains a number of links for reference.
SearchTerm:PropellantPlant
I appreciate the updates on technology which can help with carbon capture on Earth as well as application to Mars for atmosphere processing.
(th)
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The energy costs for making propellant on Mars are probably higher than any of us think. There is the intermittent cycling vs continuous operation issue I have tried to raise: batch machine operation usually costs more because of the repeated startup and shutdown operations.
There is the Sabatier reaction or its equivalents in the various devices I have seen named on these forums.
There is the electrolysis device necessary to get hydrogen and oxygen from water.
There is the energy to get the ice in the first place, and turn it into liquid water.
There is the (quite considerable) energy required to liquify the methane and the oxygen. Here on Earth, the machinery to do things like that is enormous, and very hungry for energy. I have hardly seen even a nod toward that topic on these forums.
There is the energy cost to sub-cool these liquified gases well below their boiling points, to get the higher density the Starship design uses.
And there is the continuing energy demand to keep these liquified gases that cold over very long periods of time. Cryogenics do tend to boil away, even at Martian conditions (and it will not be that cold inside the ships you intend to refuel).
All in all, there is a whopping amount of electric power needed to run all this stuff. And it is a whopping tonnage of machinery that has yet to integrated into a plant that can be sent to Mars, and also has yet to be tested for functionality and reliability at Martian conditions.
I haven't seen much of a nod toward that reality in these discussions, either.
Spacex is trying to build the transport vehicle. So EXACTLY who is building the propellant plant machinery and its power supplies (PLURAL!!!!) that will be transported in it? I've seen no answer to that. Not even in Musk's presentations.
Some bench test device in a NASA lab or a corporate lab is NOT what I am talking about!
GW
Last edited by GW Johnson (2019-10-22 08:28:43)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For GW Johnson re #32
There exists an alternate future in which a strong, real-world-tested solution to the problem you described in this post can be achieved by members of this forum.
However, for that future to come to pass, the forum would need staffing up with the right set of talents, education, real world experience and above all, motivation to participate in an all-volunteer enterprise. I've seen similar situations, and some have succeeded, but plenty have failed or not even gotten off the ground.
The world contains plenty of people who could help make something like this happen, and the NewMars forum is as good a place as any.
A kernel of the required talent appears (to me at least) to already exist in the forum, but since many hours of hard and painstaking work are required, it would be necessary to attract and retain volunteers.
That is the function of leadership.
(th)
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Hi GW,
Wondering whether you read this link from the original post on this thread...
https://www.reddit.com/r/spacex/comment … ant_plant/
I think Blake covers all the points you raise. Whether you agree with his calculations is another thing but he does reference real world machines and equipment in generating his estimates.
He's working off 1Mwe average continuous as the power requirement which I've seen elsewhere. That's pretty high! Do you think it could be higher? To put it in context, that's probably like more than 30 Tesla Model S cars working flat out. Then setting that amount of energy against producing perhaps 81 Kgs of propellant per hour (2 tons per sol)...it doesn't seem unreasonable to me because that is a lot energy!
The energy costs for making propellant on Mars are probably higher than any of us think. There is the intermittent cycling vs continuous operation issue I have tried to raise: batch machine operation usually costs more because of the repeated startup and shutdown operations.
There is the Sabatier reaction or its equivalents in the various devices I have seen named on these forums.
There is the electrolysis device necessary to get hydrogen and oxygen from water.
There is the energy to get the ice in the first place, and turn it into liquid water.
There is the (quite considerable) energy required to liquify the methane and the oxygen. Here on Earth, the machinery to do things like that is enormous, and very hungry for energy. I have hardly seen even a nod toward that topic on these forums.
There is the energy cost to sub-cool these liquified gases well below their boiling points, to get the higher density the Starship design uses.
And there is the continuing energy demand to keep these liquified gases that cold over very long periods of time. Cryogenics do tend to boil away, even at Martian conditions (and it will not be that cold inside the ships you intend to refuel).
All in all, there is a whopping amount of electric power needed to run all this stuff. And it is a whopping tonnage of machinery that has yet to integrated into a plant that can be sent to Mars, and also has yet to be tested for functionality and reliability at Martian conditions.
I haven't seen much of a nod toward that reality in these discussions, either.
Spacex is trying to build the transport vehicle. So EXACTLY who is building the propellant plant machinery and its power supplies (PLURAL!!!!) that will be transported in it? I've seen no answer to that. Not even in Musk's presentations.
Some bench test device in a NASA lab or a corporate lab is NOT what I am talking about!
GW
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Thanks, GW!
You pointed out the key feature of the Sabatier Reaction, which is flow process versus batch process. The Sabatier Reaction is strictly a gas phase reaction facilitated by means of a nickel catalyst, which is best accomplished as a flow through a tubular system packed with catalyst. The reaction is EXOTHERMIC, which means it generates heat and is self-sustaining once reaction initiates. This isn't a system which is amenable to stop-start, and requires a continuous supply of starting material, Carbon Dioxide and Hydrogen. Restarting the reaction in a flow process is NOT trivial, and may require renewal of catalyst beds. This is the strongest argument in favor of nuclear power as opposed to the diurnal cycle associated with solar. I'm sure Robert Zubrin would agree, since the pilot scale Sabatier reactor was constructed at Martin-Marietta by some aerospace engineers under his supervision back in early 1990s--which helped form the basis of the Mars Direct architecture.
Give this problem to any competent chemical engineering firm and have a complete system designed and pilot plant scale system built in less than a year. This is all very straightforward chem engineering.
The main power consumption is for compression of adequate atmosphere to run the process on the desired scale. This is going to take several compressors and some huge holding pressure vessels.
Last edited by Oldfart1939 (2019-10-22 12:22:25)
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I don't think anyone is talking about stop-start for such processes. The only issue is what minimum and maximum a particular system can handle.
Thanks, GW!
You pointed out the key feature of the Sabatier Reaction, which is flow process versus batch process. The Sabatier Reaction is strictly a gas phase reaction facilitated by means of a nickel catalyst, which is best accomplished as a flow through a tubular system packed with catalyst. The reaction is EXOTHERMIC, which means it generates heat and is self-sustaining once reaction initiates. This isn't a system which is amenable to stop-start, and requires a continuous supply of starting material, Carbon Dioxide and Hydrogen. Restarting the reaction in a flow process is NOT trivial, and may require renewal of catalyst beds. This is the strongest argument in favor of nuclear power as opposed to the diurnal cycle associated with solar. I'm sure Robert Zubrin would agree, since the pilot scale Sabatier reactor was constructed at Martin-Marietta by some aerospace engineers under his supervision back in early 1990s--which helped form the basis of the Mars Direct architecture.
Give this problem to any competent chemical engineering firm and have a complete system designed and pilot plant scale system built in less than a year. This is all very straightforward chem engineering.
The main power consumption is for compression of adequate atmosphere to run the process on the desired scale. This is going to take several compressors and some huge holding pressure vessels.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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On any mission such as the one(s) under consideration, there should be more than one such production facility (redundancy). Such plant should be scaled to a minimum of 1 metric ton per day (preferably 2 Tonnes) in order to have a single return to Earth after a 500 day residency time. This isn't going to be some tiny pilot plant design, and will definitely require human operation /supervision. What happens after this 25/7 plant breaks down? I believe without adequate maintenance and constant monitoring, the astronauts will become involuntary Mark Watneys; i.e. :S.O.L. about returning to Earth. Adequate sizing of this operation is mandatory. And 25 hours per sol operation, without interruption, is without question, one of THE pressing questions about any Mars Direct style mission architecture.
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Oldfart. The first fuel system must operate automatically as I don't see much chance of people being shipped to Mars unless there is the means of return (fuel and oxidiser) already in place. We don't seem to have a lifeboat return facility in the plans, so a ship must be available for the return flight. The alternative is that it may turn into a suicide mission if something goes wrong. It might anyway, but there is no need to increase the risk!
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elderflower-You make a valid argument, but there will be a high degree of risk associated with said mission. This is another reason SpaceX may need to consider a smaller size return ship as the on-Mars escape "lifeboat" system. A smaller product requirement in line with the original Mars semi-direct mission makes sense. I don't know of any piece of chemical process equipment capable of operating for 2 years without hands-on maintenance. Just the real world observation by a professional.
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Well I think there are a number of issues there.
Clearly we need some propellant plant redundancy which I think would favour breaking down the system into discrete channels. SpaceNut posted a Climeworks link which showed four air intakes...that would be an example...have multiple atmospheric intakes rather than just one. Then I think you can carry one or two "spares" for each element.
We might actually be taking some Mars-specific units. I've seen methane can be stored in plastic vessels. If we can have low mass storage vessels, we might be able to run with that and take spares.
Another important element I think is that even on Mission One we should have a 3D printer and basic manufacturing capability, so we can replicate substantial pieces of equipment. The Starships' cargo can of course include plenty of raw materials for parts: plastic and steel balls, glass inputs etc as well as rolled steel, steel plate etc. The Starship software could include all the design software for all parts used on the Mission (including a lot of rocket parts) as well as industrial robots and CNC lathes capable of manufacturing the parts. In addition at least a couple of the crew should be skilled engineers and craftspeople capable of fashioning a lot of parts by hand if necessary. Mission Control could of course send software designs for parts if some improvisation is required, under expert guidance.
I feel confident about the propellant plant facility. I don't feel that is a major issue. Probably storage and refuelling will be more challenging on Mars - plus there is the issue of Starship maintenance, that doesn't get a lot of attention. What sort of maintenance will be required to ready a Starship for the return journey to Earth? Also, how easy will it be to launch off bare rock with a gradient of up to 5%? On Earth you've got about 50 people watching over the launch process...on Mars with a 15 min lag in coms, they can't do that...so
how will that work?
I think all those questions are much harder than ensuring the PP facility works.
On any mission such as the one(s) under consideration, there should be more than one such production facility (redundancy). Such plant should be scaled to a minimum of 1 metric ton per day (preferably 2 Tonnes) in order to have a single return to Earth after a 500 day residency time. This isn't going to be some tiny pilot plant design, and will definitely require human operation /supervision. What happens after this 25/7 plant breaks down? I believe without adequate maintenance and constant monitoring, the astronauts will become involuntary Mark Watneys; i.e. :S.O.L. about returning to Earth. Adequate sizing of this operation is mandatory. And 25 hours per sol operation, without interruption, is without question, one of THE pressing questions about any Mars Direct style mission architecture.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Louis-
I've been in the chemical industry for a looooong time! I know that even the best designed and constructed pieces of equipment all suffer from wear in bearings and moving parts in contact with other parts. I'm confident about one thing: Murphy's Law will prevail, and Murphy was an optimist. Compressors will be subject to undue wear because of continuous operation. Bearings require lubrication. Seals will require replacements. I would LOVE to be hired as a consultant to whoever gets a contract to build a Mars-rated Carbon Dioxide collection system, as well as the Sabatier reaction system. This isn't a trivial piece of chemical process equipment, and isn't as "simple" as assumed here on this forum. It will undoubtedly be modular in design. I can see it now: The Sabatier reaction system works flawlessly for 300 days and mission launches with human crews on board. Then system has catastrophic breakdown; Murphy rejoices. Musk weeps. Crews are in deep doo-doo.
P.S. I really don't care how "confident" you are about propellant production system; there is a finite statistical probability of serious mechanical breakdown. Confidence misplaced kills people.
Last edited by Oldfart1939 (2019-10-22 16:54:33)
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I'm fully signed up to Murphy's law but I'm confident that with modular design there won't be a catastrophic failure of the whole system.
Intricate systems have worked well on rovers for over one decade. We're talking here about a two year mission and any PP equipment will be tested over and over on Earth -and possibly the Moon - before it ever goes to Mars. Yes, we all know unexpected things can happen but I think with a modular system of maybe 6 "lines" to produce the fuel/propellant, we can carry spares for every element and if necessary could produce the spares on the Mars surface with 3D printers, CNC machines and craftspeople on board. I just feel we can have a high level of confidence in all that.
But a launch procedure? When you haven't got a hundred eyes on the - what?...10? 20? 50? -critical pre-launch indicators. That just seems much higher risk, like either the few humans on Mars will miss something or an automated system will miss something a human brain might spot...
I'd prefer (if capable) to be the PP facility designer than the Mars launch designer!
Louis-
I've been in the chemical industry for a looooong time! I know that even the best designed and constructed pieces of equipment all suffer from wear in bearings and moving parts in contact with other parts. I'm confident about one thing: Murphy's Law will prevail, and Murphy was an optimist. Compressors will be subject to undue wear because of continuous operation. Bearings require lubrication. Seals will require replacements. I would LOVE to be hired as a consultant to whoever gets a contract to build a Mars-rated Carbon Dioxide collection system, as well as the Sabatier reaction system. This isn't a trivial piece of chemical process equipment, and isn't as "simple" as assumed here on this forum. It will undoubtedly be modular in design. I can see it now: The Sabatier reaction system works flawlessly for 300 days and mission launches with human crews on board. Then system has catastrophic breakdown; Murphy rejoices. Musk weeps. Crews are in deep doo-doo.P.S. I really don't care how "confident" you are about propellant production system; there is a finite statistical probability of serious mechanical breakdown. Confidence misplaced kills people.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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For all working the topic ...
There is an alternative I have not seen mentioned in recent times. It may well have been posted over the life of the forum.
There is a middle ground between a fully automated propellant plant with digital intervention similar to NASA/JPL operation of rovers, and a plant tended by humans on site.
That middle ground is a Telepresence facility on Phobos.
elderflower-You make a valid argument, but there will be a high degree of risk associated with said mission. This is another reason SpaceX may need to consider a smaller size return ship as the on-Mars escape "lifeboat" system. A smaller product requirement in line with the original Mars semi-direct mission makes sense. I don't know of any piece of chemical process equipment capable of operating for 2 years without hands-on maintenance. Just the real world observation by a professional.
If this middle ground is chosen, then the operations crew can depart Phobos without more than a deceleration burn to drop back towards Earth.
The equipment on the ground can then include high data rate remote controlled equipment, able to perform (just about) any operation a human could perform, and quite possibly do so more ably, because there would be no need to work inside a suit.
The interval between events on the ground and observation at Phobos would be less than the three seconds delay we see today, in Earth-Moon transactions.
(th)
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For all working the topic ...
The equipment on the ground can then include high data rate remote controlled equipment, able to perform (just about) any operation a human could perform, and quite possibly do so more ably, because there would be no need to work inside a suit.
The interval between events on the ground and observation at Phobos would be less than the three seconds delay we see today, in Earth-Moon transactions.
(th)
I strongly disagree. There are some operations dealing with repairs that robotics are simply incapable of performing. The mass associated with major robotic systems will NOT be insignificant. A system marginally capable of such repair would be larger than PP.
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I am happy to be didactic on this: all Phobos proposals are nonsensical diversions.
We go to the Mars surface - direct and with purpose - as Musk proposes, within 5 or 7 years, or we don't go for a very, very long time. Take your choice.
Anyone proposing a "Phobos First" approach doesn't understand what Musk is doing.
For all working the topic ...
There is an alternative I have not seen mentioned in recent times. It may well have been posted over the life of the forum.
There is a middle ground between a fully automated propellant plant with digital intervention similar to NASA/JPL operation of rovers, and a plant tended by humans on site.
That middle ground is a Telepresence facility on Phobos.
Oldfart1939 wrote:elderflower-You make a valid argument, but there will be a high degree of risk associated with said mission. This is another reason SpaceX may need to consider a smaller size return ship as the on-Mars escape "lifeboat" system. A smaller product requirement in line with the original Mars semi-direct mission makes sense. I don't know of any piece of chemical process equipment capable of operating for 2 years without hands-on maintenance. Just the real world observation by a professional.
If this middle ground is chosen, then the operations crew can depart Phobos without more than a deceleration burn to drop back towards Earth.
The equipment on the ground can then include high data rate remote controlled equipment, able to perform (just about) any operation a human could perform, and quite possibly do so more ably, because there would be no need to work inside a suit.
The interval between events on the ground and observation at Phobos would be less than the three seconds delay we see today, in Earth-Moon transactions.
(th)
Last edited by louis (2019-10-22 17:58:07)
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Louis The post #35 has the word batch in the first sentence which means limited quantity volume given as an input to the chamber to make the methane in, The start and stop is the heat to mat the reaction start in the chamber to convert co2 and H into the desired outputs of methane and water. The added heat to start the reaction is turned off once the reaction heat goes above what we are inputing such that we no longer need it on as the means to stop the chambers reaction once the heat to make it work drops.
Constant flow has not be developed for gasses go in non stop to have fuel and water come out.
The first crew use if no cargo units on mars makes the phobo landing better than a mars flyby as it should be able to come home without any refueling.
Muphys law for moving parts surely applies in the extremes of mars as did my dieing alternator today.
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Well let's cut to the chase as we say in the UK:
1. Are you saying that you can stop-start the propellant production facility with no significant adverse consequences? If so, great! If not, what is the minimum you can go to from optimal power input - 10, 30 50%?
2. There is only one credible Mars Mission before us at the moment and that is the Space X mission and it has absolutely no use for any Phobos-related activity whatsover.
Louis The post #35 has the word batch in the first sentence which means limited quantity volume given as an input to the chamber to make the methane in, The start and stop is the heat to mat the reaction start in the chamber to convert co2 and H into the desired outputs of methane and water. The added heat to start the reaction is turned off once the reaction heat goes above what we are inputing such that we no longer need it on as the means to stop the chambers reaction once the heat to make it work drops.
Constant flow has not be developed for gasses go in non stop to have fuel and water come out.
The first crew use if no cargo units on mars makes the phobo landing better than a mars flyby as it should be able to come home without any refueling.
Muphys law for moving parts surely applies in the extremes of mars as did my dieing alternator today.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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SpaceNut-
In general, gas phase catalyzed reactions are not particularly amenable to batch reactions. Take advantage of the mixing provided by gas flow through a column packed with catalyst.
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