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#51 2016-02-04 10:42:46

kbd512
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Registered: 2015-01-02
Posts: 5,112

Re: NASA could make 'Skylab II' first deep space 'home'

RobertDyck wrote:

And my concern was that using a EUS LH2 tank as the ITV would be too big. A single deck hab would be smaller, consequently lower mass. But that would be too small for the LH2 tank for launch. Hmm. Two LH2 tanks? Nah, too complicated. If you can't use the upper stage tank as your habitat, then may as well launch dry.

Skylab II is larger than required, but cheaper than using ISS-derived hardware and the mass is the same or less.  In other words, it's perfect for human exploration of Mars.  Since no goofy mass and volume allocation schemes are required to use it, you can be certain that NASA will use ISS-derived hardware.  They'd much rather demonstrate ingenuity rather than practicality.

RobertDyck wrote:

A soft habitat could fit within a Falcon 9 fairing, but that would create problems with artificial gravity. You want a firm floor to stand on, for so furniture doesn't move around when you walk, and simply for structural support. So that brings me back to a large diameter habitat. We could shrink it a bit. Mars Direct was designed on purpose to maximize use of the large diameter core stage. Robert Zubrin said so in his book. Skylab did pretty well with a 6.6 metre diameter, but sleeping quarters were vertical. You can do that in zero-G, but not with artificial gravity.

Velcro or secure the storage bags and furniture.  Alternatively, use the central support structure that both Bigelow Aerospace and NASA intended to use when the inflatable habitat was developed.  The soft floors will still be relatively rigid.

RobertDyck wrote:

Again, with a single deck, the walls will be weight bearing to hold the ceiling and floor together. Against pressure. So you can have a flat floor, and a low dome to the ceiling, similar to the end of an ISS module. Or the roof of MDRS or FMARS. Not a hemispherical dome. That is part of the design of a dedicated habitat, not a propellant tank.

That works best for the MDV/MSH.  Alternatively, HESCO barriers and small pits also work well, but require earth moving equipment.

RobertDyck wrote:

So again I come to the same conclusion. Either self-launching, or not use a propellant tank.

It's a neat concept, but not required.

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#52 2016-02-04 20:04:30

SpaceNut
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From: New Hampshire
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Posts: 24,368

Re: NASA could make 'Skylab II' first deep space 'home'

I have begun to wonder how many deep space habitats or Skylab II's we should have and what types of mission we could perform if we had them with artificial gravity and propulsion to reach any selected journeys....

We now have the starting of the ability to do more than just go to the moon and to plan missions to mars with them so why not do venus and other NEO's such as Eros or even to Cere's or Vista...Man could run more than one mission at a time if we have more than one deep space habitat to use.

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#53 2016-02-04 21:42:42

kbd512
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Posts: 5,112

Re: NASA could make 'Skylab II' first deep space 'home'

SpaceNut wrote:

I have begun to wonder how many deep space habitats or Skylab II's we should have and what types of mission we could perform if we had them with artificial gravity and propulsion to reach any selected journeys....

I wonder about how much it will cost us to certify Skylab II as flight hardware.

SpaceNut wrote:

We now have the starting of the ability to do more than just go to the moon and to plan missions to mars with them so why not do venus and other NEO's such as Eros or even to Cere's or Vista...Man could run more than one mission at a time if we have more than one deep space habitat to use.

The only way we can run two missions at one time is if NASA's budget is increased.  I think everyone here would double their budget in a heartbeat.

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#54 2016-05-16 15:53:06

RobertDyck
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From: Winnipeg, Canada
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Re: NASA could make 'Skylab II' first deep space 'home'

We discussed replacement modules for the station in "Space Policy". I did some "back of the envelope" calculations. A workshop as large as the Skylab workshop could be launched wet. Replace the upper stage of Falcon 9 with a LOX/LH2 upper stage that launches itself into orbit. Skylab was originally designed to launch wet as the upper stage of a Saturn 1B, do the same. I asked if we could use the Exploration Upper Stage from SLS. Turns out that's a little too large, it's 8.4m diameter while Falcon 9 is 3.66m diameter, and EUS has too much mass. But a stage the same size as S-IVB, or more to the point the same size as Skylab workshop, could work. Saturn 1B used RP1/LOX for its first stage, LH2/LOX for the upper stage. Saturn V used RP1/LOX for its first stage, LH2/LOX for 2nd & 3rd. Falcon 9 currently uses RP1/LOX for both stages. So this would use a Falcon 9 first stage with RP1/LOX, that could be recovered, the upper stage would self-launch into orbit using LH2/LOX. S-IVB and of course Skylab workshop was 6.6m diameter. Falcon 9 is rated for a fairing 5.0m diameter. This might work as-is, but any wider would require modified first stage gimbals than can swivel further. This wider upper stage may require that. This new workshop would require modern aluminum lithium alloy with modern friction stir welding, and would require a common bulkhead between LH2 and LOX tank. Thermal blankets and micrometeoroid shield would have to be modern, like an ISS module, but that could be the exterior skin for launch, no fairing. The solar arrays would have to be folded with a small fairing for launch, just like Skylab. Dragon already does that (without fairing failure like Skylab), this would just be bigger (like Skylab). It would require a nose cone fairing, but that's all. Would also require some RCS thrusters to rendezvous with ISS, so the station arm can grab it and berth like Dragon. Call it "Dragon on steroids". It would be the same size as the Skylab workshop, no airlock, no multiple docking adapter, no Apollo telescope mount, but ISS already has those. Modern electronics would not survive freezing in LH2, and thin membranes of water processing equipment for life support would not survive. So the module would have to be launched without those things, they would be installed later.

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#55 2016-05-17 16:46:57

GW Johnson
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From: McGregor, Texas USA
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Re: NASA could make 'Skylab II' first deep space 'home'

So,  don't do what we did in the 1960's.  Use the modern inflatables instead.  You need little in the way beyond today's launch rockets to send such things to orbit,  and dock them together.  For no more than 10% of the cost we paid to build ISS. 

Further,  if you abandon the zero-gee idea from the outset,  and instead go for a spinning baton with artificial gravity,  you can have the very thing we need for journeys beyond the moon,  at a very affordable cost. 

All it takes is not thinking we have to do exactly,  and only,  what was done before. 

Had the original 1958 incarnation of NASA felt that it could not do anything not ever done before,  then US astronauts would NEVER have flown in orbit at all,  much less have gone to the moon by 1968-1969.  (That would be Apollo 8,  and Apollos 10 and 11.) 

I fear our modern NASA is simply incapable of doing such things. 

GW

Last edited by GW Johnson (2016-05-17 16:48:57)


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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#56 2016-05-17 21:13:23

RobertDyck
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Re: NASA could make 'Skylab II' first deep space 'home'

GW: A question about alloy. This article (Production at SpaceX) says "Falcon 9’s propellant tank walls and domes are both made from an aluminum-lithium alloy." The same page mentions Dragon, so the quote implies Dragon is not made of aluminum-lithium alloy? Why? I saw a TV documentary about development of the Boeing 777 airliner (not the 787 Dreamliner). That documentary said aluminum-lithium alloy produces micro-fractures when machined, so screw holes have said fractures. Micro-fractures don't creep in that alloy like they do in other aluminum alloys, so it's Ok. But vehicle inspection crews are trained to treat micro-fractures as failure. Then there's the issue of micro-fractures in one part is Ok, but in another is not. The reason is different alloys, but they were afraid of mistakes by normal operational maintenance staff. This raises the question whether this alloy is the right material for a station module. Dr. Robert Zubrin selected aluminum-lithium alloy for the Mars Direct habitat, according to his book "The Case for Mars". And he wrote that book himself. I also notice Falcon 9 is a reusable first stage and SpaceX uses that alloy for that stage. Is there any reason this alloy could not be used for a station module, Deep Space Habitat, or Mars surface habitat?

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#57 2016-05-18 10:01:38

GW Johnson
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Re: NASA could make 'Skylab II' first deep space 'home'

I don't know a whole lot about aluminum-lithium alloy.  It seems to be all the rage for one-shot propellant tanks.  We'll see if Spacex can re-use them,  and what the lifetime might really be.  Micro-cracking is very definitely something to worry about. 

That kind of tank is not a Dewar,  you are looking at a single wall tank.  Can't store cryogenics in it for very long at all,  just a few hours. 

As to whether you could make habitable modules out of it,  I suppose you could,  if the micro-cracking doesn't lead to failure.  But,  you'd have to prove that it doesn't.  The risk is rather similar to fatigue in other metals.  It takes lots of cycling loads to find out. 

I'm not at all sure that you get that much benefit from lithium-aluminum over more conventional aluminum alloys for manned modules,  especially if micro-cracking around fastener holes does prove to be a long-life issue like fatigue.  We understand the older alloys much better. 

I'd tend to be conservative about such things,  and use the newer less-well-understood alloy for one-shot or limited-life unmanned stuff. 

GW


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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#58 2016-05-19 20:50:50

SpaceNut
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Re: NASA could make 'Skylab II' first deep space 'home'

Well the tanks could be used as feed stock in a smelting unit to make what ever we would want for shapes from it just feed into a laser sintering unit and we can make habitats from it....

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#59 2016-05-20 12:09:30

GW Johnson
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Re: NASA could make 'Skylab II' first deep space 'home'

I would never,  ever use a sintered metal part for a pressure vessel of any kind at all!  Sintered metal part properties are lousy:  very brittle,  rather weak,  porous enough to leak right through the material.  Not good for much but toys.  I would never buy a wrench,  pliers,  or screwdriver made of that stuff.  I wouldn't use it as a coffee cup:  it would seep right through. 

Which is also why I do not trust 3-D printed metal parts.  That IS sintering in the form of laser sintering.  That technology still has a very long way to go to produce anything approaching our "regular" metal materials. 

In sintering,  the applied heat (laser or other) almost but not quite welds the particles together.  These "welds" are very weak,  and there is lots of porosity left between the particles.  Why should it be surprising then,  that the result isn't even anywhere near as good as a simple casting?  And simple castings are in turn far crummier than a real upset-forged part made from a proper billet in a mill.  With sintering,  there is no heat treat,  no work hardening,  nothing.  Just brittle,  weak crap that leaks.

Using things like that as highly-loaded or pressure-vessel parts in a rocket motor is foolish to the point of real stupidity,  in my opinion as an engineer of 4 decades experience.  That's why the rockets that have been made so far using such stuff are all low-chamber pressure items.  And there's no history behind any of them to even suggest reliability.  I certainly noticed that.  Everybody else should,  too. 

GW

Last edited by GW Johnson (2016-05-20 12:20:37)


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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#60 2018-02-19 17:38:46

SpaceNut
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Re: NASA could make 'Skylab II' first deep space 'home'

Wow started before the Deep space habitat was a concept...

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#61 2018-02-20 21:21:00

GW Johnson
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Re: NASA could make 'Skylab II' first deep space 'home'

A correction for post 59 just above:  last year I visited an outfit that has pretty well solved the porosity problem with 3-D printed metal parts.  Near full density and near full strength (above 90% of wrought parts).  They are one of very few who have achieved this so far.  More will,  but it will take time.

They were evasive when I asked about printed part elongation capability.  They admitted it was still less,  but not by how much.  Low elongation = brittle behavior,  period,  end-of-discussion.  If the part you make must endure either shock or vibration or any kind of sudden loading,  you DO NOT want a 3-D printed part.  It will fail brittle-ly on you.

But the printed coffee cup will now hold the coffee,  if (and only if) these guys make it. 

GW


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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#62 2018-02-20 21:28:16

RobertDyck
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Re: NASA could make 'Skylab II' first deep space 'home'

Gary: SpaceX uses 3D printed parts in their engines. Proposal for the F-1B engine would use 3D printed parts as well, and I understand the gas generator that was demonstrated was made that way. How can rocket engine parts be made this way if they have the problem you describe?

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#63 2018-02-20 21:37:12

SpaceNut
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Re: NASA could make 'Skylab II' first deep space 'home'

secondary processing of surfaces and heat treating
http://www.spacedaily.com/reports/Suike … r_999.html
prevent-3-d-printed-walls-from-collapsing-falling-lg.jpg

Hopefully we will not get to side tracked as we need to begin to build in orbit even if its just raw or semi raw feed stock for such devices to make use of.

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#64 2018-03-27 16:44:59

SpaceNut
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Re: NASA could make 'Skylab II' first deep space 'home'

ULA laying the foundations for an Econosphere in CisLunar space

2018-03-22-162638-1170x673.jpg

United Launch Alliance (ULA) President and CEO Tory Bruno has provided a new overview of his company’s role in a proposed “Econosphere” in space. Although it will take decades to fully realize its potential, ULA hardware is set to provide the key elements via its CisLunar 1000 roadmap, allowing numerous commercial companies to come together to create a self-sustaining community of around 1000 people in the space between the Earth and the Moon.

The CisLunar 1000 plans revolve creating an in-space economy that would tap into the vast amount of resources that could be harnessed from objects such as Near Earth Asteroids (NEA) and on the surface of the Moon.

Eventually, the community would become self-sufficient via in situ resource utilization (ISRU), while becoming economically viable via the prospecting of precious materials that are rare on Earth but abundant in space.

“What we understand today is there’s over 17,000 of these (varying range of NEAs) that come in different classes. Best estimates, there are two trillion kilograms of industrial metals residing in that region,” noted Mr. Bruno during his address to students at the University of Colorado Boulder.

“Materials like Aluminum, Titanium, Iron, Cobalt, Nickel and so on. That’s about a 1000 years of the total production we have here on Earth.”

He added there are more of the precious materials – such as gold, silver and platinum – in this region that has ever been mined in the history of humankind, while also referencing the large amounts of water – a key element for ISRU – that resides on the Moon.

2018-03-22-150427.jpg

2018-03-22-161431.jpg

2018-03-22-154419.jpg

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#65 2018-03-28 10:24:39

GW Johnson
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From: McGregor, Texas USA
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Re: NASA could make 'Skylab II' first deep space 'home'

Belatedly replying to RobertDyck in post #62 above:  Obviously some of these firms have figured out how to get both near-wrought density and strength,  plus acceptable levels of elongation capability,  out of 3-D printed metal parts.  I don't know how they do all of that,  but it is becoming obvious that they do. 

Comments on cis-lunar plan in post #64:  I like some of what I see,  particularly the depictions of using the Bigelow B-330 (or some variant thereof) for habitation spaces.  Unless I am mistaken,  the depicted ACES stage is the revised 4-engine Centaur stage that is to be the second stage of ULA's Vulcan launcher. 

Point 1:  left completely out is how anyone is going to get an NEA into cis-lunar orbit for processing of any kind.  That is a major delta-vee with an enormously-massive payload.  My own view is that it might be more feasible to take the processing factory to the NEA,  rather than try to bring an NEA to a factory in cis-lunar space. Pushing on a carbonaceous chondrite is very likely to disrupt it instead of move it.  Small objects seem to be drier,  and most appear to be loose rubble piles because they are dry. 

Point 2:  it is still quite premature to be claiming water is plentifully available on the moon.  That remains to be seen and verified as real ground truth from actual surface missions. 

Point 3:  where is the solar flare radiation shelter?  I see none depicted. 

Point 4:  where is the artificial spin gravity to keep a crew healthy enough to stay longer than 6 months to at most a year?  I see none depicted.

This depiction is full of unstated assumptions.  It is assumptions like these that will kill you.  The joke (which isn't funny because it is mostly true) is that's why we spell "assume" the way we do:  because it makes an "ass" out of "u" and "me".

GW

Last edited by GW Johnson (2018-03-28 10:27:28)


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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#66 2018-03-28 13:40:39

Oldfart1939
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Registered: 2016-11-26
Posts: 2,270

Re: NASA could make 'Skylab II' first deep space 'home'

All I know about 3D printing is what's available on various websites by manufacturers of the apparatus; that = not too much. The key to success, w/r to elongation, brittleness, etc., would seem to revolve about the temperatures at which this additive manufacturing takes place. Perhaps some sort of post-manufacture processing involving heat treatment of the manufactured parts would be beneficial?   That could potentiate the brittleness to a certain degree. It would also be possible to improve the mechanical properties of the 3D printed parts through use of different alloys than were initially tested in this application. I obviously don't know what I'm talking about, but only relying on a now 60 year old course in metallurgy and my few remaining brain cells still in contact with one another.

Last edited by Oldfart1939 (2018-03-28 13:41:38)

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#67 2018-03-28 22:08:15

Oldfart1939
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Registered: 2016-11-26
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Re: NASA could make 'Skylab II' first deep space 'home'

My late wife used to describe the proposal in #64 above as "pie in the sky." Quite appropriate, eh? It appears that ULA is already drooling over the amounts of $$$$ that lies in wait for them should this monstrosity of a project be realized. I wish to go on record as seconding GW's comments about the "new habitat for man" lacking any provision of artificial gravity and lack of a solar flare radiation shelter. But the concept would make Josef Mengele proud of the (in)human medical consequences involved in this concept. I've been brainstorming a possible structure utilizing a series of Bigelow modules forming the radial service passageways to habitats at the extreme ends and a central hub with a radiation shelter, shielded with the food supplies and water for the station. It would initially be a dumbbell shape capable of rotation about the hub to generate synthetic gravity  sufficient to maintain health and normal toilet usage. Ideally there would subsequently be either 4 or 6 pairs of radial passageways and habitats; the structure could be reinforced with strong cable ties between habitat modules, and everything reinforced with cables to the hub as well. Who knows? Perhaps we could wind up with a Bigelow version of the von Braun "bicycle wheel," as a lunar station? I personally think it preposterous and unnecessary. A POX on the NASA mission planners. They are all too worried about taking that giant step for all mankind and falling on their faces as they stumble in the doorway. In lots of other endeavors, particularly as test pilots--no pain, no gain. We didn't arrive at this fantastic new threshold to deep space without some risks being taken. But these planners now propose to expose astronauts to long zero gravity and solar flare events w/o adequate protection.

Last edited by Oldfart1939 (2018-03-28 22:08:52)

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#68 2018-04-08 19:04:34

SpaceNut
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Re: NASA could make 'Skylab II' first deep space 'home'

This luxury space hotel could be up and running in four years

A Silicon Valley startup called Orion Span yesterday announced plans to open a luxury hotel in low-Earth orbit by 2022, and you can reserve a room for $80,000. Just be aware that that figure is only a down payment for a 12-day stay, which runs a stratospheric $9.5 million per person. Dubbed Aurora Station, the orbiting inn will offer space tourists with deep pockets a chance to experience life like an astronaut.

“That experience entails…growing food in space, running science experiments, doing astronaut certification,” In addition to witnessing luminous auroras against the blackness of space and gazing down on Earth as it passes below at a distance of 200 miles, guests will be able to enjoy an onboard “holodeck” inspired by the one known to fans of “Star Trek.” Construction of one Aurora Station “module” will begin in 2019, according to the company, with plans to launch it into orbit by late 2021. Additional modules could be attached later.

Between 2001 and 2009, seven “private astronauts” rode Russian-made Soyuz rockets to the International Space Station for brief stays.

One was Richard Garriott, a video game developer and entrepreneur who reportedly paid $30 million for a two-week stay aboard the ISS in 2008.

Now to find the spare change for the trip.....

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#69 2019-09-05 17:41:02

tahanson43206
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Registered: 2018-04-27
Posts: 8,559

Re: NASA could make 'Skylab II' first deep space 'home'

For SpaceNut .... this story is a follow on to the link you provided in #68 above ...

https://www.yahoo.com/lifestyle/world-f … 01366.html

It's not related to NASA at all, so it doesn't fit with the topic, but I'm working with the post you provided.  If you prefer a different topic, please move the post.

9th)

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#70 2019-09-05 18:17:09

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 24,368

Re: NASA could make 'Skylab II' first deep space 'home'

This version of the board does not split and merge to other topics as did others in the past.


The image in the article is circa 2001: A Space Odyssey. movie and thou there are possibly simular topics its ok...

The spoked wheel is a favorite of many as its rotating to get artifical gravity and by design it gives the maximum floor space when rotating.

de890b5448f5018dd198cc75dbdc601d

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