Author Topic: ITS Development Updates and Discussion Thread  (Read 351285 times)

Online lamontagne

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Re: ITS Development Updates and Discussion Thread
« Reply #280 on: 10/20/2016 12:49 am »
It doesn't matter when designing parts in CAD. But when you build and test a dev article, bigger is definitely much more expensive. Filling that 12m LOX tank for a single cryo test would cost hundreds of thousands of dollars.
Only if you throw away the LOX when you're done.

Throwing the LOX away is what is usually done. They won't have a tank big enough to store it. Unless they build 2 test tanks and keep pumping the LOX between them, only replacing boiloff losses.  ;) I think if they had two they would have mentioned it.

Yes, I agree it was likely just boiled off.  Lox is just energy, really.  A few big compressors running for a few days.  You might want to close the vent for a few hours and watch the pressure rise, while you're at it.  From a safe distance.

Offline Lumina

Re: ITS Development Updates and Discussion Thread
« Reply #281 on: 10/20/2016 01:46 am »
Exactly. Musk skipped the "Exploration" phase vehicle with equal capability and went straight to "Colonization" phase with greater CAPACITY. I think that substantially increases the risk that it will never be built, unfortunately.

A 1/6th scale upper stage launched on Falcon Heavy could prove every ITS concept for something like 1/10th the dev and testing cost.

Maybe size doesn't matter as to the development cost. Most of the development is the same whether big or small.

Right. I think there are several system architecture advantages in Musk's plan. It has beauty in its simplicity, if you can learn to not fear the sizes of the pieces.

Offline GWH

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Re: ITS Development Updates and Discussion Thread
« Reply #282 on: 10/20/2016 02:13 am »
For those who worry about the difference is scale between the Falcon 9 and ITS, and have forgotten their history, I give you the difference in scale between gemini and Saturn 5, and the difference in scale between Falcon 9 and ITS.

Whats all those things between Gemini and Saturn V?

Personally less worried about difference in size between F9 and ITS but rather Dragon and ITS spaceship.
« Last Edit: 10/20/2016 02:17 am by GWH »

Offline Robotbeat

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Re: ITS Development Updates and Discussion Thread
« Reply #283 on: 10/20/2016 02:49 am »
remember the rule - every experiment should be finished before death of the experimentator. musk do not have time for subscale multi year approach company.
I think this is the primary constraint, here. Musk is pretty young still, but this project is going to take a LONG time. He doesn't think he has a decade to just prove out a subscale system first. There's also the possibility that he could die early or otherwise lose control of SpaceX.

Also, there is, I think, some expectations-management being done by Elon, here. By proposing something ludicrous but still possible, it pushes his competitors to much greater efforts than they otherwise would.

I think asking the question "Is Musk trying to egg on Bezos?" is often a fruitful one.

EDIT:The egging on of one rocket leader to another is a game that I think von Braun and Korolev played with each other, dragging their countries to space and even to the Moon.
« Last Edit: 10/20/2016 02:51 am by Robotbeat »
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Offline su27k

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Re: ITS Development Updates and Discussion Thread
« Reply #284 on: 10/20/2016 04:30 am »
Besides, if they went this route with the mini ITS there would be a good chance (build it in to the design from the get go) it could function as a reusable upper stage for F9/FH for regular launches and allow for rapid development and design iterations and building up to repeated reuse like they have done with F9 up till now - while using paid for launches to do so.

Requiring F9/FH to test mini ITS is not necessarily a good thing, it means modification of existing pad, range approval and fees, interrupting their commercial launches, and risk of taking out their existing pad if something went wrong.

A full scale ITS Ship should be able to be tested just like F9R-Dev1 or DC-X, which may actually have some advantage from operation point of view.

Offline GWH

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Re: ITS Development Updates and Discussion Thread
« Reply #285 on: 10/20/2016 06:01 am »

Requiring F9/FH to test mini ITS is not necessarily a good thing, it means modification of existing pad, range approval and fees, interrupting their commercial launches, and risk of taking out their existing pad if something went wrong.

Launch facilities in Brownsville coming online could offset that disruption,  and if something does go wrong.. well that pretty well justifies all the effort of development at a smaller scale for new systems.

Offline envy887

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Re: ITS Development Updates and Discussion Thread
« Reply #286 on: 10/20/2016 07:32 pm »
Somehow people don't seem to get that developing any generation of spaceship is extremely expensive.  The concept is relatively cheap, it's those thousands of hours of detailed engineering for everything from a fuel line to a nose fairing that will not be recoverable for the later vehicle.  All those simulations, all the documentation, etc...
If it then goes to just a few vehicles, it's crazy from a business viewpoint. 

A cargo variant ITS spaceship scaled to Falcon Heavy could most likely put a ~10t commsat through supersynchronous GTO and return to land while all 3 FH boosters RTLS. Might make more business sense for 5t commsats too, compared to zero-margin extra-toasty F9 droneship landings. This is basically the fully reusable Falcon upper stage Musk said he was temped to pursue, but he prefers to focus on the full-size ITS.

Offline CuddlyRocket

Re: ITS Development Updates and Discussion Thread
« Reply #287 on: 10/20/2016 08:58 pm »
For those who worry about the difference is scale between the Falcon 9 and ITS, and have forgotten their history, I give you the difference in scale between gemini and Saturn 5, and the difference in scale between Falcon 9 and ITS.

Whats all those things between Gemini and Saturn V?

From the left: Mercury-Redstone; Mercury-Atlas 2; Gemini-Titan II; Apollo-Saturn IB; Apollo-Saturn V.

(If memory serves!)
« Last Edit: 10/20/2016 08:58 pm by CuddlyRocket »

Offline Kansan52

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Re: ITS Development Updates and Discussion Thread
« Reply #288 on: 10/20/2016 09:05 pm »
Looks correct. But going on memory as well.

Offline GWH

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Re: ITS Development Updates and Discussion Thread
« Reply #289 on: 10/20/2016 09:31 pm »

From the left: Mercury-Redstone; Mercury-Atlas 2; Gemini-Titan II; Apollo-Saturn IB; Apollo-Saturn V.


Ah right, Mercury THEN Gemini.  Was thinking it was the opposite and being cheeky about the incremental steps taken leading up to Saturn V.  But yeah - Titan II to Saturn 1 (which was a cluster, apt analogy to FH) to Saturn 5. Perfect analogy for historical massive increase in size and capabilities and comparison to SpaceX now.

But still, I don't think the scale up to the booster is the big challenge.  Going to a rapidly reusable upper stage/spaceship from an expendable stage + reusable capsule is where an intermediate step is really needed IMO.
And going back to the historical example, wasn't Saturn 1 mostly built to test fly components of the Apollo program?
« Last Edit: 10/20/2016 09:49 pm by GWH »

Offline JamesH65

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Re: ITS Development Updates and Discussion Thread
« Reply #290 on: 10/21/2016 08:07 am »
I wonder if by going for the full scale ITS as a first iteration, they actually might save a little money. They will have less constraints on size, and weight, which means designwise and manufacturing, an easier job. The use of many multiple Raptors also means one development path for the engine, which would be the same whether large or small ITS. Additional dev work on plumbing, but that's just plumbing, not in the same league as the engine development itself.

A lot of the hull dev work would also be the same for either - the tech for the large scale carbon  composite manufacture.

As others have said, making it big does increase manufacturing and testing costs for dev articles.

Lots of swings and roundabouts.

Offline Llian Rhydderch

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Re: ITS Development Updates and Discussion Thread
« Reply #291 on: 10/24/2016 02:28 am »
It doesn't matter when designing parts in CAD. But when you build and test a dev article, bigger is definitely much more expensive. Filling that 12m LOX tank for a single cryo test would cost hundreds of thousands of dollars.
Only if you throw away the LOX when you're done.

Throwing the LOX away is what is usually done. They won't have a tank big enough to store it. Unless they build 2 test tanks and keep pumping the LOX between them, only replacing boiloff losses.  ;) I think if they had two they would have mentioned it.

Trucks?  Take it back to the LOX plant.

Rent the LOX for the test; pay for any LOX used and transportation/handling/overhead costs to the LOX producer as negotiated as part of the deal; return the rest back into the supply system to be sold as LOX as usual; cleaned/refined if necessary.
Re arguments from authority on NSF:  "no one is exempt from error, and errors of authority are usually the worst kind.  Taking your word for things without question is no different than a bracket design not being tested because the designer was an old hand."
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Offline DOCinCT

Re: ITS Development Updates and Discussion Thread
« Reply #292 on: 10/25/2016 07:18 pm »
In the recent reddit Elon was asked: "What level of completion is the interior habitable area layout of ITS at, and when might we expect to see renderings of it?"
His reply was: "Will aim to release details of the habitation section when we have actual live mockups. Maybe in a year or two."
Not willing to wait that long I decided to try my hand at layouts for 3 decks of the habitation section, which I have posted to the the L2 Level: SpaceX F9/FH/ITS Renderings  http://forum.nasaspaceflight.com/index.php?topic=35307.0
As that forum is mainly for images rather than extended discussion, I created this post instead (hopefully that's OK to do).

« Last Edit: 10/25/2016 07:33 pm by DOCinCT »

Online lamontagne

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Re: ITS Development Updates and Discussion Thread
« Reply #293 on: 10/25/2016 07:56 pm »
In the recent reddit Elon was asked: "What level of completion is the interior habitable area layout of ITS at, and when might we expect to see renderings of it?"
His reply was: "Will aim to release details of the habitation section when we have actual live mockups. Maybe in a year or two."
Not willing to wait that long I decided to try my hand at layouts for 3 decks of the habitation section, which I have posted to the the L2 Level: SpaceX F9/FH/ITS Renderings  http://forum.nasaspaceflight.com/index.php?topic=35307.0
As that forum is mainly for images rather than extended discussion, I created this post instead (hopefully that's OK to do).
Only 42 berths?  It does seem a little small for 100 people, or perhaps I have misunderstood the quantities?

Offline DOCinCT

Re: ITS Development Updates and Discussion Thread
« Reply #294 on: 10/25/2016 08:26 pm »
In the recent reddit Elon was asked: "What level of completion is the interior habitable area layout of ITS at, and when might we expect to see renderings of it?"
His reply was: "Will aim to release details of the habitation section when we have actual live mockups. Maybe in a year or two."
Not willing to wait that long I decided to try my hand at layouts for 3 decks of the habitation section, which I have posted to the the L2 Level: SpaceX F9/FH/ITS Renderings  http://forum.nasaspaceflight.com/index.php?topic=35307.0
As that forum is mainly for images rather than extended discussion, I created this post instead (hopefully that's OK to do).
Only 42 berths?  It does seem a little small for 100 people, or perhaps I have misunderstood the quantities?

It's reasonable for early missions.  Musk did say 100 (or more) eventually.  Space starts to get tight as you go up levels. In a linear design as in a sub, you can pack more in.
I see upper levels being flight crew and infirmary and then more recreation space.

Update:  I did a quick floor plan for the 4th deck (flight crew infirmary)  space is tight.
« Last Edit: 10/25/2016 10:51 pm by DOCinCT »

Online lamontagne

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Re: ITS Development Updates and Discussion Thread
« Reply #295 on: 10/25/2016 08:30 pm »
In the recent reddit Elon was asked: "What level of completion is the interior habitable area layout of ITS at, and when might we expect to see renderings of it?"
His reply was: "Will aim to release details of the habitation section when we have actual live mockups. Maybe in a year or two."
Not willing to wait that long I decided to try my hand at layouts for 3 decks of the habitation section, which I have posted to the the L2 Level: SpaceX F9/FH/ITS Renderings  http://forum.nasaspaceflight.com/index.php?topic=35307.0
As that forum is mainly for images rather than extended discussion, I created this post instead (hopefully that's OK to do).
Only 42 berths?  It does seem a little small for 100 people, or perhaps I have misunderstood the quantities?

It's reasonable for early missions.  Musk did say 100 (or more) eventually.  Space starts to get tight as you go up levels. In a linear design as in a sub, you can pack more in.
I see upper levels being flight crew and infirmary and then more recreation space.
Wonder if the ITS Spaceship design is stretchable, rather like an aircraft, or if it's a whole new design of you add a few meters to the length? Three more floors would do wonders for living space, at the cost of about 7.5m in extra length...

Offline Terra Incognita

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Re: ITS Development Updates and Discussion Thread
« Reply #296 on: 10/25/2016 08:32 pm »
I like the idea of the spiral staircase for the on Mars 0.4g which could also be used in zero g.

Well done in putting the effort in, I appreciate it but the ITS will spend most of its time in zero-g this layout is almost 100% designed for gravity. It also if you don't mind me saying it looks a bit grim rather than cruise ship.

I think we should be looking to high-end yacht manufacturers design and layout not the navy.

This architect student has done some very sexy inspiring designs for the ITS internal layout. It has a way to go but it looks like a lot more of a fun design: http://imgur.com/a/SOGnu

Offline Kaputnik

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Re: ITS Development Updates and Discussion Thread
« Reply #297 on: 10/25/2016 08:44 pm »
In the recent reddit Elon was asked: "What level of completion is the interior habitable area layout of ITS at, and when might we expect to see renderings of it?"
His reply was: "Will aim to release details of the habitation section when we have actual live mockups. Maybe in a year or two."
Not willing to wait that long I decided to try my hand at layouts for 3 decks of the habitation section, which I have posted to the the L2 Level: SpaceX F9/FH/ITS Renderings  http://forum.nasaspaceflight.com/index.php?topic=35307.0
As that forum is mainly for images rather than extended discussion, I created this post instead (hopefully that's OK to do).
Only 42 berths?  It does seem a little small for 100 people, or perhaps I have misunderstood the quantities?

It's reasonable for early missions.  Musk did say 100 (or more) eventually.  Space starts to get tight as you go up levels. In a linear design as in a sub, you can pack more in.
I see upper levels being flight crew and infirmary and then more recreation space.
Wonder if the ITS Spaceship design is stretchable, rather like an aircraft, or if it's a whole new design of you add a few meters to the length? Three more floors would do wonders for living space, at the cost of about 7.5m in extra length...


Doubtful, as it would change the OML and centre of gravity. Perhaps expansion into the cargo space would be feasible.
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Online lamontagne

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Re: ITS Development Updates and Discussion Thread
« Reply #298 on: 10/25/2016 08:56 pm »
Using the cargo area might do the trick, although there seems to be a pressure bulkhead there, with the cargo unpressurized in the presentation spaceship.  If the spaceship Musk showed is the Heart of Gold, i.e. a very early ship, then it will not have 100 people aboard.  So perhaps we should not try to pack 100 people in.  20 to 30 might be the upper limit to that arrangement.
After all, we should expect all passenger, mixed and all cargo versions.
Isn't there a door/area too many in the airlock? I would have though an outer door an an inner door would be enough.

Offline Robotbeat

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Re: ITS Development Updates and Discussion Thread
« Reply #299 on: 10/25/2016 09:05 pm »
Musk implied the ITS spaceship could be expanded in the future, but the comments were in context of 200 to 400+ passengers in the ITS. I wouldn't imagine it'd be simple, but it wouldn't have to be.
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

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