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Author Topic: Space X Interplanetary Transport System  (Read 12587 times)

Offline Moose

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Re: Space X Interplanetary Transport System
« Reply #30 on: September 28, 2016, 06:52:23 pm »
Raptor engine test at McGregor site.  I think this is a subscale demonstrator and that the full size version is to be tested at Nasa Stennis.


Full size engine, just without the extended bell if a flight article. Raptor is actually quite compact.

Offline Byeman

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Re: Space X Interplanetary Transport System
« Reply #31 on: September 28, 2016, 06:59:27 pm »
There is no existing expertise to land a man on the Moon let alone on Mars no matter how much I would like to be wrong.

Nonsense.  You are wrong.   It exists.  Landing on a planet is easy and has been done many times.

Offline DrRansom

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Re: Space X Interplanetary Transport System
« Reply #32 on: September 28, 2016, 07:11:17 pm »
The problem with the plan, as far as is presented, is that the operational design represents a huge risk. Musk requires the ITS have reliability on the order of modern day transport aircraft. That reliability can only be ensured after a huge number of flight tests. For the 787, Wikipedia says that the flight test program involved 1,700 flights.

No rocket system has flown a fraction of that number of flights. Saturn V flow ~1% of the 787 test flights. The space shuttle flew <10% of the total number of 787 test flights.

Unless Musk can magically assure reliability or ensure several hundred flights of the largest rocket booster ever, he cannot achieve the per-flight reliability he requires.

Which brings us to the next logistical problem. The ITS will represent a mammoth pre-flight and launch risk. It'll have explosive power on the order of a tactical nuke. How does Musk even begin a flight test program with that rocket? He has to ensure system reliability to a high level before he can even begin flights, because of the risk the rocket poses.

I don't think his architecture is remotely feasible, because it requires a reliability level never yet seen on a space launch system. To get that reliability, he needs a flight rate never yet seen on a space launch system. And that flight rate is needed for a rocket which requires a massive reliability to even begin flying and whose size is far too large for any commercial use.

All of this is before we begin dealing with the Martian trip architecture, which doesn't seem to be very solid. For one, he will need a bunch of launch sites and a bunch of rockets and an industrial amount of propellant.

Those problems aside, what is interesting is the new rocket engine and the rocket engine design. If Musk can achieve his design goals there, that will be very useful and very impressive.

Offline JeffB

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Re: Space X Interplanetary Transport System
« Reply #33 on: September 28, 2016, 08:28:46 pm »
I still don't understand the attraction of going to Mars, especially 100 or 200 people at a time.  The infrastructure required to support them would be massive and the likelihood of disaster would be significant. 

This whole drive for Mars strikes me as a rather poorly thought out flag-planting exercise.  We still need to build a significant level of capability in the near-Earth region before we start seriously thinking about moving hundreds of people to Mars.  It's every bit as dangerous to live on as the moon is except its 10x further away from support and in a gravity well that's about 10x deeper to boot.

Online Orionblamblam

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Re: Space X Interplanetary Transport System
« Reply #34 on: September 28, 2016, 09:07:44 pm »
I still don't understand the attraction of going to Mars[/qote]

I don't understand the appeal of living in Los Angeles, Manhattan, Tokyo or London, but a lot of people do.


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The infrastructure required to support them would be massive and the likelihood of disaster would be significant. 

That's why cowards would be ill-advised to go.

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This whole drive for Mars strikes me as a rather poorly thought out flag-planting exercise. 

What's wrong with planting flags, if you plants homes and farms and businesses right next to 'em?

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We still need to build a significant level of capability in the near-Earth region before we start seriously thinking about moving hundreds of people to Mars.

Why? What infrastructure could you build in LEO or GEO that would greatly enhance transport to Mars?

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It's every bit as dangerous to live on as the moon is except its 10x further away from support and in a gravity well that's about 10x deeper to boot.

You say that like it's a bad thing. Getting the hell away from the control of Earth has a whole lot of appeal. At some point the population and infrastructure of Mars would be self-sustaining... whether that's 1000 people or 10,000, who knows; but the moon  will always be an outpost of Earth until people start shovign around tens-of-kilometer scale carbon asteroids and water comets.
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Offline JeffB

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Re: Space X Interplanetary Transport System
« Reply #35 on: September 28, 2016, 10:27:42 pm »
I still don't understand the attraction of going to Mars
I don't understand the appeal of living in Los Angeles, Manhattan, Tokyo or London, but a lot of people do.


Quote
The infrastructure required to support them would be massive and the likelihood of disaster would be significant. 

That's why cowards would be ill-advised to go.

Quote
This whole drive for Mars strikes me as a rather poorly thought out flag-planting exercise. 

What's wrong with planting flags, if you plants homes and farms and businesses right next to 'em?

Quote
We still need to build a significant level of capability in the near-Earth region before we start seriously thinking about moving hundreds of people to Mars.

Why? What infrastructure could you build in LEO or GEO that would greatly enhance transport to Mars?

Quote
It's every bit as dangerous to live on as the moon is except its 10x further away from support and in a gravity well that's about 10x deeper to boot.

You say that like it's a bad thing. Getting the hell away from the control of Earth has a whole lot of appeal. At some point the population and infrastructure of Mars would be self-sustaining... whether that's 1000 people or 10,000, who knows; but the moon  will always be an outpost of Earth until people start shovign around tens-of-kilometer scale carbon asteroids and water comets.

It IS a bad thing.  Distance doesn't automatically guarantee independence, Mars is just as likely to be treated as an outpost of Earth for a period as well until they can make themselves self-sustaining, and even then they may not want to let you go.  Set up a small colony in the Asteroids if you're that desperate to be independent, the smaller the outpost probably the better and like Grizzly Addams, be prepared to move on as soon as you see the "smoke of another mans fire".  Ultimately though, you know that "government" will follow.  Once you have that critical mass of people, the political class will appear and hey presto, you'll be back where you started, metaphorically.

The question in this case is why would you build your completely experimental, largely untested, off-world colony on a planet 6 months away when you could build it just as easily on the moon which is only 3 days away?  Once you've worked how to do that reliably and repeatedly in what is effectively our back-yard, then you'll be ready to face the challenges of landing and building a colony on something the size of Mars.  But then why would you bother?  The gravity still isn't high enough to not affect the human physiology significantly. The atmosphere is toxic and the radiation levels are very high given Mars' near non existent magnetic field.  Once you've mastered the necessary skills, it'd be far easier to build centrifuges with sufficient shielding to support larger populations at normal g's from materials mined from the moon and asteroids and built with fuel mined from same.

What could we do in LEO or GEO?  Well, given that the biggest cost of doing any of this is getting up the first 150 miles, technologies that could assist that process like skyhooks or other tether based momentum transfer systems would be extremely useful.  Especially if your initial target is the moon because the mass transfer back from the moon either as processed resources or just rocks is sufficient to keep pushing people and supplies up the well.

This is all just my opinion of course, obviously you see other benefits of going straight to Mars that I missed.




Offline RLBH

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Re: Space X Interplanetary Transport System
« Reply #36 on: September 29, 2016, 02:19:16 am »
The problem with the plan, as far as is presented, is that the operational design represents a huge risk. Musk requires the ITS have reliability on the order of modern day transport aircraft. That reliability can only be ensured after a huge number of flight tests. For the 787, Wikipedia says that the flight test program involved 1,700 flights.

No rocket system has flown a fraction of that number of flights. Saturn V flow ~1% of the 787 test flights. The space shuttle flew <10% of the total number of 787 test flights.
Soyuz-U has had 784 flights of which 764 were successful; the entire R-7 family has 1,859 flights of which 1,744 are successful. Now granted, by aircraft standards that's still only just out of testing, and that's the only launcher that has come close to mass production, but it has been achieved.

Offline sferrin

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Re: Space X Interplanetary Transport System
« Reply #37 on: September 29, 2016, 04:37:04 am »
The problem with the plan, as far as is presented, is that the operational design represents a huge risk.

How could it not?  Lots of things present risk.  Sailing to the "New World", going to the moon, etc. etc.  The bold move forward and overcome those challenges.  The timid stay home and waste away.


Musk requires the ITS have reliability on the order of modern day transport aircraft. That reliability can only be ensured after a huge number of flight tests. For the 787, Wikipedia says that the flight test program involved 1,700 flights.

And?  How reliable were the first turbojets?  Maybe we shouldn't have built one until we knew the first one would have the reliability of a GE90?  I mean how could we have been so heartless to force people onto those first 707s?

No rocket system has flown a fraction of that number of flights. Saturn V flow ~1% of the 787 test flights. The space shuttle flew <10% of the total number of 787 test flights.

And?  How do you expect to flight 1700 flights without, you know, flying 1700 flights?

Unless Musk can magically assure reliability or ensure several hundred flights of the largest rocket booster ever, he cannot achieve the per-flight reliability he requires.

Maybe he should wait until reliability magically appears and THEN start to build his rockets?

Which brings us to the next logistical problem. The ITS will represent a mammoth pre-flight and launch risk. It'll have explosive power on the order of a tactical nuke. How does Musk even begin a flight test program with that rocket? He has to ensure system reliability to a high level before he can even begin flights, because of the risk the rocket poses.

Just plain Chicken Little scare mongering.  It wouldn't be significantly more dangerous than a Saturn V or Shuttle.

I don't think his architecture is remotely feasible, because it requires a reliability level never yet seen on a space launch system.

And never will be as long as the mentality of "we can't move until there is zero risk" exists. 
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Offline flanker

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Re: Space X Interplanetary Transport System
« Reply #38 on: September 29, 2016, 04:56:26 am »
Sure, if one ignores the reason for the delays time after time. FH in 2012 is not the same FH in 2016. Between then and now they have been through 3 major versions of Falcon 9 with one more coming up next year. So if anything - you just proved my point. ;)

Now you're being silly.

Missing deadlines is not a good thing, no matter what the excuse.

I am not saying it is a good thing - i am saying there is a reason for it. And the reason for it is that Falcon 9 development simply outruns Falcon Heavy development since the later is based on the former. First FH was based upon v1.0 F9. v1.0 was replaced with v1.1 which was radically different and basically a whole new rocket. v1.2 was a heavy evolution of v1.1 but none the less it still required extra work for the octaweb. Which also applied to FH. Etc etc.

There is no existing expertise to land a man on the Moon let alone on Mars no matter how much I would like to be wrong.

Nonsense.  You are wrong.   It exists.  Landing on a planet is easy and has been done many times.



I don't think his architecture is remotely feasible, because it requires a reliability level never yet seen on a space launch system.

And never will be as long as the mentality of "we can't move until there is zero risk" exists.

Nailed it. "Nothing is worth doing until there is 100% safety guarantied." We always assume a certain risk level in our daily lives, and yet we just deal with it.

Regarding "why send crew up first", Elon's comments;

Quote
Elon says that this is the plan if the refueling process is quick, like a couple weeks or less. If it takes a lot longer, then the spacecraft will be launched first without people, and then whenever itís all refueled and ready to go, a spacecraft carrying just people will be launched and it will deliver the crew to the spacecraft for an Earth orbit rendezvous.

http://waitbutwhy.com/2016/09/spacexs-big-fking-rocket-the-full-story.html
Push the envelope,watch it bend.

Offline DrRansom

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Re: Space X Interplanetary Transport System
« Reply #39 on: September 29, 2016, 11:28:39 am »
Soyuz-U has had 784 flights of which 764 were successful; the entire R-7 family has 1,859 flights of which 1,744 are successful. Now granted, by aircraft standards that's still only just out of testing, and that's the only launcher that has come close to mass production, but it has been achieved.

Thanks for that, so there is a rocket with the sufficient number of flights.

Sferrin - you fundamentally misunderstood my issue with Musk's proposal. His Mars colonization proposal requires changing the rocket launch paradigm from 'single-launches at a time' with very low launch rates to a reliability of a modern jet liner. It took 50 years of constant jet flights to reach today's jet-liner reliability. Space launches are nowhere near the reliability required for multiple heavy rocket launches in a week with sufficiently cheap infrastructure to make the whole system economical.

This isn't a problem of accepting zero risk. This is a problem of understanding just what Musk is implicitly proposing. He implicitly proposes shifting space launch costs, via the development of low-maintenance high-reliability systems. That is the space-launch Holy Grail which has eluded developers for 50 years. He is following the underpants gnome school of development:
- design cutting edge rocket
- ...
- airline like reliability, operational cost, and safety to enable high-volume interplanetary travel!

Musk never stated how he is going to fill in the '...' If we base rocket development upon the airline and automobile industry, it will take 50 years of relatively high-volume use to understand what is required. Rockets have barely begun to be designed for high-volume use. Nobody has the experience required to design for high-volume use. Musk gave no proposal about how to fill that knowledge and experience gap.

Now, to a degree Musk's Mars proposal is constrained by SpaceX. SpaceX is a rocket company, so the Mars transport will be a traditional rocket. That may not be the best option. Perhaps another technological breakthrough (high-ISP electric propulsion) will allow Mars colonization without as many space launches.

However, all of the above is besides another point: why go to Mars in the first place? Is there anything of value there for people on Earth?

And, we are still jumping ahead of the first problem. SpaceX has to build a rocket with the cutting edge features:
- brand new, high performance engine
- Nearly all-composite structure, especially unlined tanks
- Two gas/liquid internal pressurization (I don't know the technical word here, but basically replacing helium.)
- Validating the use of 42 engines for launch and flight, including the attendant problems that causes: launch platform design, acoustic loading, etc.

I'm glad SpaceX is looking at doing the above. If it can succeed, then space launch will be much cheaper than today.

PS: Christopher Columbus got lucky.

Offline sferrin

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Re: Space X Interplanetary Transport System
« Reply #40 on: September 29, 2016, 01:23:55 pm »
Sferrin - you fundamentally misunderstood my issue with Musk's proposal.

No, I understand exactly what you mean.  Basically, he's smoking dope because nobody has operated a rocket like an airliner, or has 1700 flights on one design.  That about it?  My response to that is (again)- "and?"   One has to start somewhere, and you can't really wait until you have 1700 launches under your belt before finally decided to undertake the mission.  And they won't be going full rate right out of the gate but would ramp up over years, if not decades.  The first Comet airliner didn't have the reliability of a 787.  Should they have put the brakes on air transport until they'd achieved 787-levels of reliability?


His Mars colonization proposal requires changing the rocket launch paradigm from 'single-launches at a time' with very low launch rates to a reliability of a modern jet liner. It took 50 years of constant jet flights to reach today's jet-liner reliability. Space launches are nowhere near the reliability required for multiple heavy rocket launches in a week with sufficiently cheap infrastructure to make the whole system economical.

You can't seem to see the forest for the trees.  He's not proposing going from 1 launch one month to 6 a week the next.  What he's proposing is similar to the process airlines took but on an accelerated time frame.  As for cost, space launches never will reach those levels without trying.  Do you think air travel was as cheap in 1950 as it is today?  Should we have stopped air travel until it was cheap enough for everybody?  How exactly would that have been achieved?

This isn't a problem of accepting zero risk. This is a problem of understanding just what Musk is implicitly proposing. He implicitly proposes shifting space launch costs, via the development of low-maintenance high-reliability systems. That is the space-launch Holy Grail which has eluded developers for 50 years. He is following the underpants gnome school of development:
- design cutting edge rocket
- ...
- airline like reliability, operational cost, and safety to enable high-volume interplanetary travel!

There were those who thought similarly of flying people across oceans on airplanes.  (On, not in, because in 1900 one "rode" those things.)

Musk never stated how he is going to fill in the '...' If we base rocket development upon the airline and automobile industry, it will take 50 years of relatively high-volume use to understand what is required. Rockets have barely begun to be designed for high-volume use. Nobody has the experience required to design for high-volume use. Musk gave no proposal about how to fill that knowledge and experience gap.

Why would he?  Seriously.  You think he'd lay out a mile long gantt chart for the public at a one hour media event? 

However, all of the above is besides another point: why go to Mars in the first place? Is there anything of value there for people on Earth?

Oh, I don't know, how about survival of the species? 

PS: Christopher Columbus got lucky.

No such thing.  If he hadn't done it somebody else would have. 
« Last Edit: September 29, 2016, 01:25:54 pm by sferrin »
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Offline DrRansom

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Re: Space X Interplanetary Transport System
« Reply #41 on: September 29, 2016, 02:15:08 pm »
Sferrin - had Musk said words to the effect that: "I'm embarking ok a decade long quest to push rocket operations to airplane levels" I'd be ok. Instead, we get this nice "wow" picture of a rocket and a cool CGI video, followed by hordes of people saying "I'm so glad that at least someone is willing to try to dream." That same crowd conveniently passes over the revolution SpaceX will have to achieve before this Mars plan can work. They also ignore that Musk's dream has been the dream for spaceflight for the past 50 years. His dream was the dream of the Space Shuttle, the NASP, the Venture Star. All programs which failed to reach that goal.

Musk has demonstrated successful rocket landing, he hasn't demonstrated reuse and reliability with the vehicle compromises required for reuse. (this is a recent development)

I wanted to hear how he plans to reach the reliability, because that's the major problem. Him dreaming or laying out a plan makes him just like every other developer of a major new space-launcher. (Albeit, landing a rocket does give him credibility)

Re: Columbus - given that his math was wrong, it is an open question if anyone would have tried for another century, or until sailing ships had enough range to reach across the combined Atlantic and Pacific. There's an interesting counter-factual. And Columbus did get lucky, if there was no America, his ships would have starved before they reached his destination, Asia.

Offline blackstar

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Re: Space X Interplanetary Transport System
« Reply #42 on: September 29, 2016, 02:58:10 pm »
I wanted to hear how he plans to reach the reliability, because that's the major problem. Him dreaming or laying out a plan makes him just like every other developer of a major new space-launcher. (Albeit, landing a rocket does give him credibility)

Keep in mind that his dream also left out a bunch of other things:

-the in-space element, including long-duration life-support.
-the on-Mars element, including life-support, spacesuits, habitation modules, etc.
-who is going to develop those other things (note that Musk did not say that SpaceX is going to do any of that other stuff).
-who is going to pay for it all.

If it is not SpaceX developing all that other stuff, then it's gotta be some combination of other space hardware developers, such as Lockheed Martin, Boeing, NASA, etc. And the people who are most rabid about SpaceX think that all those other actors are bloated, expensive, inefficient, and generally lousy (I've seen people on the internet who hate Boeing, NASA, et. al.). So does the overall dream collapse because SpaceX is not going to do all of it but needs other actors to come on board, or evolve?

And where is the magical funding going to come from if Elon is not going to pay for it all?

Offline sferrin

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Re: Space X Interplanetary Transport System
« Reply #43 on: September 29, 2016, 03:34:23 pm »
Musk has demonstrated successful rocket landing, he hasn't demonstrated reuse and reliability with the vehicle compromises required for reuse. (this is a recent development)

Don't just gloss over that achievement, particularly the at-sea landings.  Of all the major players, SpaceX has the most credibility. 

Re: Columbus - given that his math was wrong, it is an open question if anyone would have tried for another century, or until sailing ships had enough range to reach across the combined Atlantic and Pacific.

Not really.  There were other explorers.  Had Columbus sailed off into the unknown, never to be heard of again, others would have tried. 

"or until sailing ships had enough range to reach across the combined Atlantic and Pacific."

So never then right?  After all, how would they ever know which ships had the range if they never made the trip, or if they could sail that far if they'd never done it before?

This seems particularly appropriate:

"31. (Mo's Law of Evolutionary Development) You can't get to the moon by climbing successively taller trees."
« Last Edit: September 29, 2016, 03:38:35 pm by sferrin »
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Offline DrRansom

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Re: Space X Interplanetary Transport System
« Reply #44 on: September 29, 2016, 03:52:13 pm »

Don't just gloss over that achievement, particularly the at-sea landings.  Of all the major players, SpaceX has the most credibility. 

That's very true. He does have a ton of credibility in rocket building. That's why I'm not discounting him building the ITS rocket.

Quote
Not really.  There were other explorers.  Had Columbus sailed off into the unknown, never to be heard of again, others would have tried. 

"or until sailing ships had enough range to reach across the combined Atlantic and Pacific."

So never then right?  After all, how would they ever know which ships had the range if they never made the trip, or if they could sail that far if they'd never done it before?

This seems particularly appropriate:

"31. (Mo's Law of Evolutionary Development) You can't get to the moon by climbing successively taller trees."

People roughly knew the distance from Europe to Asia. They also would have had a decent idea about the range of their ships across open ocean. Combine those two facts and you have the necessary technological conditions for a proper exploration of the Atlantic route to Asia.

The historical analogy would be using a Titan II for moon launch missions and it working. I.E. using a totally unsuited vehicle and it working out by happenchance.