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#301 2016-10-29 16:13:21

RobS
Banned
From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
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Re: Musk's plans for Mars

You are right, GW. This is a common misunderstanding when people critique Musk. They complain he didn't solve the housing problem or the oxygen problem or the food problem. He proposes to solve the biggest, most expensive, and complex problem of them all: the transportation problem. My guess is that those problems are much simpler to solve, because there's sunlight, an atmosphere full of CO2, and you have to site your base near a water supply.

I wouldn't be surprised if, a half century after people start landing on Mars, a reliable pressurized residential unit with a life support system won't be available for perhaps twice as much as a house on Earth (excluding the cost of land, which is getting very expensive on Earth but will remain cheaper on Mars for a long time). Houses on Earth already come with wells, solar panels, and all sorts of systems that were not available in the 19th century: running water, hot water, heat, air conditioning, wifi, etc. The price of these systems has come down immensely and their reliability has greatly increased. Adding solar power, batteries, a sabatier, and an air purification system is fairly simple. Making the house airtight and regulating its interior temperature are probably the big challenges. But submarines do these things already. Because of an atmosphere and a water supply, these things will be easier to do on Mars than in space because you don't have to close your recycling to such a high degree.

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#302 2016-10-29 17:52:56

kbd512
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Registered: 2015-01-02
Posts: 4,615

Re: Musk's plans for Mars

My critique of Mr. Musk's plan has nothing to do with solving every problem related to living on Mars.  It has everything to do with the extreme inefficiency of chemical propulsion for the type of operation he wants to mount.  His plan is to send a vehicle that weighs twice as much as a Space Shuttle from the surface of the Earth to the surface of Mars and back again, many times, without significant refurbishment.  The rockets aren't free and the non-existent infrastructure that has to be delivered to the surface of Mars to support his plan isn't free.

I'm certain that someone on Earth has tried to figure out how to make a CONEX box fly.  If you put enough thrust behind it, it'd work, but it's no more a sensible replacement for a cargo airplane than a horse is a viable means of transportation for someone living in New York who wants to visit LA on the weekend.

If every other problem related to living on Mars was magically solved tomorrow, we still need substantially more efficient propulsion to make travel to and from Mars a routine and affordable operation.  The costs associated with interplanetary space flight won't be substantially reduced until we solution that problem.

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#303 2016-10-29 18:14:30

RobS
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From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
Website

Re: Musk's plans for Mars

We'll just have to disagree with you, kbd. Chemical propulsion is "extremely inefficient" compared to a lot of things we don't have; warp drive, antimatter propulsion, and fusion engines being three. The point is: we don't have them, and we won't have fusion engines for probably half a century or more. Regardless whether you are making electricity with fusion or not, whether you are creating a "leaky" magnetic containment or not, you still need to create a magnetic containment that produces extremely high temperature and pressure. No one knows how to do that in a unit weighing a few tens of tonnes in zero gee and in space, functioning for a liog period of time, and we won't have such a fusion engine for a long time.

The inefficiency of chemical propulsion, frankly, is irrelevant to getting people to Mars in 4 to 9 months IF THE COST OF PROPELLANT IN LOW EARTH ORBIT IS CHEAP ENOUGH. Even the Falcon Heavy is a game changer, where that is concerned. NASA people have been talking about using xenon propellant for ion engines for decades. The cost of producing xenon on the surface of the earth is higher than the price of gold! That makes sense if the cost of launching thirty tonnes of xenon to orbit is a few hundred million bucks. If the cost of launching propellant to earth orbit falls to a million bucks a tonne, it makes no sense at all to use xenon propellant. Even launching twenty times as much hydrogen peroxide monopropellant would be cheaper!

As for Musk's enormous rockets, he has an engineering team that clearly knows what it is doing; it has produced from scratch a remarkable rocket that is, for the very first time, actually reusable. I am not sure any of us on this forum have the engineering experience to critique his system from an engineering point of view. If he thinks he can land a huge thing on Mars, refuel it, and send it back to Earth, who is to say he can't, from the point of view of relevant engineering experience?

His system is not the one I would develop; but I am an amateur. It's not the system GW would develop, and he DOES know engineering. It's not the system Robert Dyck would develop, and he has some experience as well. But none of us have a successful rocket under our belts and $10 billion in launch orders in our pocket, either.

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#304 2016-10-29 22:17:31

kbd512
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Registered: 2015-01-02
Posts: 4,615

Re: Musk's plans for Mars

RobS wrote:

We'll just have to disagree with you, kbd. Chemical propulsion is "extremely inefficient" compared to a lot of things we don't have; warp drive, antimatter propulsion, and fusion engines being three. The point is: we don't have them, and we won't have fusion engines for probably half a century or more. Regardless whether you are making electricity with fusion or not, whether you are creating a "leaky" magnetic containment or not, you still need to create a magnetic containment that produces extremely high temperature and pressure. No one knows how to do that in a unit weighing a few tens of tonnes in zero gee and in space, functioning for a liog period of time, and we won't have such a fusion engine for a long time.

RobS,

If you don't invest in more efficient propulsion technology, you never have the possibility of reaping the benefits that more efficient propulsion technology could deliver.  If our predecessors had used that line of thinking for determining what to spend their money on, we'd still be staring up at the moon, wondering what it was like to walk on the moon.  Fortunately for us, they didn't think that way.

The Saturn V was a non-existent rocket using non-existent propulsion technology when President Kennedy declared that we'd go to the moon.  It was every bit as fanciful as fusion or warp drive, given the technology that existed at that time.  We made the decision that we wanted something better, we put the might of science and industry behind it, we built and tested it, and we rode that rocket to the moon.  And yes, there were plenty of failures along the way.  Can anyone seriously argue that our perseverance did not pay off?

RobS wrote:

The inefficiency of chemical propulsion, frankly, is irrelevant to getting people to Mars in 4 to 9 months IF THE COST OF PROPELLANT IN LOW EARTH ORBIT IS CHEAP ENOUGH. Even the Falcon Heavy is a game changer, where that is concerned. NASA people have been talking about using xenon propellant for ion engines for decades. The cost of producing xenon on the surface of the earth is higher than the price of gold! That makes sense if the cost of launching thirty tonnes of xenon to orbit is a few hundred million bucks. If the cost of launching propellant to earth orbit falls to a million bucks a tonne, it makes no sense at all to use xenon propellant. Even launching twenty times as much hydrogen peroxide monopropellant would be cheaper!

A cheap reusable chemical rocket hasn't materialized in over half a century of chemical rocket flight.  If I used your line of argument, it has never existed and therefore never will exist.  The FDR doesn't use gold for propellant, it uses Lithium.  The lab device is using aluminum.  The propellant required to drive 61t to Mars would cost $10.8M.  If 1t to LEO costs $1M, the cost of using a chemical rocket will still far outweigh the cost of using the fusion rocket.

The solution to the requirement to deliver 1950t worth of propellant to LEO at a cost of $1.95B can't possibly be delivery of 420t of propellant that costs $113M, for a total cost of $533M.

On that note, the only thing I want to get to Mars quickly are humans.  If the transit time is substantially shorter, substantially less consumables are required, which also costs $1M per ton to deliver to LEO.  The longer duration transit times are a compounding problem.

As for Musk's enormous rockets, he has an engineering team that clearly knows what it is doing; it has produced from scratch a remarkable rocket that is, for the very first time, actually reusable. I am not sure any of us on this forum have the engineering experience to critique his system from an engineering point of view. If he thinks he can land a huge thing on Mars, refuel it, and send it back to Earth, who is to say he can't, from the point of view of relevant engineering experience?

RobS wrote:

His system is not the one I would develop; but I am an amateur. It's not the system GW would develop, and he DOES know engineering. It's not the system Robert Dyck would develop, and he has some experience as well. But none of us have a successful rocket under our belts and $10 billion in launch orders in our pocket, either.

Good point.

As I've said before, I wish him all the luck in the world.  Unfortunately, economics will play a greater role in his success than luck.

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#305 2016-10-30 07:18:34

RobS
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From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
Website

Re: Musk's plans for Mars

KBD, I have no problem in investing in fusion rockets. There is a high likelihood that the technology will be mastered eventually. But I am not inclined to pin my hopes on a small company that is spending just a few million a year; not yet. Fusion engines presumably will take billions to develop and years to perfect to the point where they are reliable. Musk is spending money now and has a timetable for getting people to Mars in about a decade. I suspect he'll succeed in more time than that, but before NASA, even if NASA did adopt a project to develop a fusion engine.

And Musk is not planning to launch his propellant into orbit with reusable Falcon Heavies. He projects that the ITS booster can put stuff into low Earth orbit at something like $20,000 or $25,000 per tonne and he can get a tonne to Mars for something like $140,000. He has a plan to spend $10 billion to do it. Will he spend more than $10 billion? Quite possibly. Will launch costs be more than that? Certainly, at first. His cost projection is not an immediate cost reduction, but an eventual one. To use an example, we know a Falcon 9 can put up to 20 tonnes into LEO for $60 million. A single reuse will get you 13 tonnes to orbit for $40 million; about the same price per tonne. But the "Block 5" version of Falcon 9 will be designed for at least ten reuses. It will put 13 tonnes into LEO. For how much? We don't know. About a year from now, that will be figured out. In two years, we'll know how often a Falcon Heavy configuration can be reused and what it will cost. In 3 or 4 years, we'll have some idea what the initial cost of the ITS booster will be and how many reuses its "Block 1" version will be capable. How many versions will be needed before we get an ITS booster able to be reused 1,000 times? We don't know. That's the version needed to slash the launch costs to $25,000 per tonne. What other demands for such a booster will exist? How many boosters will be needed to meet launch demand if each can be used 1,000 times? Right now, that booster would meet world wide launch demand for a decade! But you can't lower launch costs on the demand for Mars flights alone. We can guess that there will be a LOT of other launch demands for such a vehicle; orbital tourism, even lunar tourism will grow a lot. But we don't know.

What we do know is someone with a very innovative engineering team and deep pockets has a plan that must be theoretically viable, based on their unique experience.

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#306 2016-10-31 21:15:13

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,099

Re: Musk's plans for Mars

Power consumption to make methane in this article:
https://www.inverse.com/article/21492-s … ction-mars

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#307 2019-10-06 17:34:46

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,099

Re: Musk's plans for Mars

remembering the other plans for a ship to mars and how it keep changing

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#308 2019-10-06 18:39:47

kbd512
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Registered: 2015-01-02
Posts: 4,615

Re: Musk's plans for Mars

SpaceNut,

A fusion driven rocket can achieve 50% useful payload mass fraction with a 3 month transit time.  I'm primarily interested in sending people and the implements of civilization to Mars, not giant gas tanks loaded with cryogenic explosives.  We need something better than refinements to mid-20th century rocket technology for humanity to expand beyond Earth.

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#309 2019-10-07 18:12:46

SpaceNut
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From: New Hampshire
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Posts: 23,099

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#310 2019-10-07 18:29:45

tahanson43206
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Registered: 2018-04-27
Posts: 7,326

Re: Musk's plans for Mars

For SpaceNut re #309 ....

Thanks for those links. In this post I'd like to focus on the "9 places" report, because I am confident it will drive Louis crazy!

https://www.businessinsider.com/spacex- … ise-2019-9

By using solar (or perhaps nuclear) energy, Musk says, a process called the Sabatier reaction could turn water and carbon dioxide in the thin Martian atmosphere into methane. That fuel, along with oxygen extracted from the water, could be used to refuel Starships for return flights to Earth as well as provide breathable air and drinking water.

I am happy to see this first hint that the SpaceX time is moving toward including nuclear power in their thinking.

(th)

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#311 2021-05-30 16:59:42

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 885

Re: Musk's plans for Mars

Mars mission: Elon Musk shares glimpse of Starship before first orbital flight
https://www.express.co.uk/news/science/ … latest-ont

Nelson uses Chinese Mars landing as a warning to Congress
https://spacenews.com/nelson-uses-chine … -congress/

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#312 2021-06-01 11:39:57

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 885

Re: Musk's plans for Mars

Elon Musk gave a Greek name to SpaceX’s Mars launch platform
https://greekcitytimes.com/2021/05/31/e … rs-launch/

Musk's SpaceX reveals ambitious plans to launch a Starship rocket to MARS from an 'ocean spaceport' in 2022
https://www.dailymail.co.uk/sciencetech … light.html

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#313 2021-06-27 11:50:22

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 885

Re: Musk's plans for Mars

Elon Musk’s outsider status ‘key to SpaceX success’
https://www.theaustralian.com.au/busine … f5f0f78831

China reveals plans to colonise space with a Mars base, cargo fleets, alien cities, and a ‘sky ladder’
https://news.yahoo.com/china-reveals-pl … 17208.html

Musk Criticizes NASA, Says Spaceships Should Fly Between Space Stations
https://twitter.com/TheMarsSociety/stat … 4900643840
Elon Musk took to Twitter (surprise!) to criticize NASA for signaling it would continue prohibiting direct cooperation between the agency and China indefinitely.

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#314 2021-06-27 13:30:57

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,099

Re: Musk's plans for Mars

The China versus other nations and the stations is more about ITAR than about providing a service for either.
Complain to loudly and that could be the end....national security is a big thing

The china ladder from heaven might be possible from a geo orbit but that firs step is a dozy if you miss....

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#315 2021-06-27 13:56:54

louis
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From: UK
Registered: 2008-03-24
Posts: 6,865

Re: Musk's plans for Mars

Well, if CCP China are serious about the 2033 date and not trying to pull the wool over our eyes, then that's great. Space X should have a six year lead on them  - three landing trips. Space X will have a head start.

But we might see two nations developing on Mars. An English-speaking Free Republic of Mars and a Chinese CCP-PLA Colony.

Mars_B4_Moon wrote:

Elon Musk’s outsider status ‘key to SpaceX success’
https://www.theaustralian.com.au/busine … f5f0f78831

China reveals plans to colonise space with a Mars base, cargo fleets, alien cities, and a ‘sky ladder’
https://news.yahoo.com/china-reveals-pl … 17208.html

Musk Criticizes NASA, Says Spaceships Should Fly Between Space Stations
https://twitter.com/TheMarsSociety/stat … 4900643840
Elon Musk took to Twitter (surprise!) to criticize NASA for signaling it would continue prohibiting direct cooperation between the agency and China indefinitely.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#316 2021-06-27 23:31:20

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 885

Re: Musk's plans for Mars

Not Another...negative nancy debbie downer


A business, podcast and marketing at the New York University Stern School?

SCOTT GALLOWAY:
https://www.businessinsider.com/scott-g … ets-2021-6
Colonizing Mars will not happen in our lifetime and the billionaire obsession with space makes absolutely no sense


Elon Musk Criticizes NASA, Says Spaceships Should Fly Between Space Stations
https://futurism.com/the-byte/elon-musk … -amendment

Last edited by Mars_B4_Moon (2021-06-27 23:33:30)

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#317 2021-06-28 00:12:26

Rxke
Member
From: Belgium
Registered: 2003-11-03
Posts: 3,667

Re: Musk's plans for Mars

Mars_B4_Moon wrote:

Not Another...negative nancy debbie downer

I stopped reading at:  SCOTT GALLOWAY

Guy has interesting, even valid points on other subjects, but is too set in his thinking towards big companies to see the bigger picture of spaceflight. /shrugs/

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#318 2021-06-28 00:18:50

Rxke
Member
From: Belgium
Registered: 2003-11-03
Posts: 3,667

Re: Musk's plans for Mars

Started reading anyway, it's a sad piece. Full of cheap shots and misrepresentations.

And sometimes just ... Making no sense whatsoever:

"Blue Origin and SpaceX are serious space-hauling companies. Apparently, it's also a profitable business. Said Blue Origin CEO Bob Smith: "We make money on every flight.""

wut? In what parallel dimension is BO doing flights to space????

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#319 2021-06-28 06:13:53

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,326

Re: Musk's plans for Mars

For Rxke re #318

Thanks for your review of the Debbie Downer pieces!  It's good to know there are people earning income by publishing such sentiment. 

Regarding your closing question ... I'm not sure if that is your text, but assuming it is, what is your definition of the word "space"?

It's possible what Bob Smith is describing is flights to the Von Karmann line, which the company is doing, and those are (apparently) profitable because there are customers willing to pay for a few minutes of weightless flight.

Perhaps your comment is about the use of the word space in this context?

Oh! I think I see the problem .... what Bob Smith said was captured by a reporter/writer, who used inaccurate language ...

The writer also lumped Blue Origin and SpaceX together, although their achievements have been in quite different realms.

Blue Origin is taking a methodical approach to flight, using the far more difficult hydrogen and oxygen combination ...

Google came up with this:

The New Shepard propulsion module is powered using a Blue Origin BE-3 bipropellant rocket engine burning liquid hydrogen and liquid oxygen, although some early development work was done by Blue Origin on engines operating with other propellants: the BE-1 engine using monopropellant hydrogen peroxide; and the BE-2 ...
Blue Origin New Shepard - Wikipedia
en.wikipedia.org › wiki › New_Shepard
About Featured Snippets

Blue Origin has not lost a single vehicle.

I think this is a tortoise/hare comparison ...

Use of Hydrogen is the better choice for the long run, on a number of counts.

****
Thanks again for your many posts bringing old topics back to life with new links and comments.

(th)

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#320 2021-07-14 05:40:40

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 885

Re: Musk's plans for Mars

Elon Musk Shares SpaceX's Starship Raptor Production Plans To Colonize Mars By 2050
https://www.tesmanian.com/blogs/tesmanian-blog/raptors

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#321 2021-07-28 12:47:54

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 885

Re: Musk's plans for Mars

The imperator of Mars
If you are a billionaire like Musk, you can indulge your imagination ...

https://www.thestatesman.com/opinion/th … 86361.html

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