Blue Origin Thread (merged)

[Chabadarl]

6 minutes ago, shynung said:

Why would anyone spent fortunes building a railroad there?

I think he's a little vague about the true raisons but I can cite one persone that is going spend a fortune trying....

 

[Vaporized Steel]

There is something I don't understand, probably because I'm not a engineer
I've been following spaceX activities for years and I dreamed about Elon's plan coming into fruition and well, it's going into a satisfactory direction from a Layman's perspective.

The way I see this endeavor is like the passenger airline industry since the wright brothers. But more specifically the Jet airline industry later on.
SpaceX needs to get the right kind of plants in operation not just for production but also for maintenance and testing of already used stages. They already do that, I know but I mean in a way to try identify problems before they happen kind of way. Especially for a rocket that's supposed to launch 100 real living creatures

Because my gut feeling here is that if let's say Elon delivers his promise of creating his BFR and it succeeds all mission objectives including recovery that the same rocket is going to fail in the next 3, 6 or perhaps 9 subsequent missions due to constructional failure. Think about cracks due to multiple refueling operations, re-exposure of the same parts many times over again in between near absolute zero and 2000+ Fahrenheit (depending on what stage we talk about)

Failure during x many times wouldn't be bad ofcourse, even if he manages to launch the thing only once it is a achievement, but I'm talking more long term here. Elon mentions a active maintenance program, but I haven't really been able to understand how that would look like.

The reason I bring this up is because although we managed to recover a rocket stage it has never been tried to use that same piece that many times in order to get that desired price tag that Elon Musk has sugar coated for us.

What are your expectations where failure because of re-use could go wrong, and how would a maintenance program look like to tackle these issues before it creates a problem?

Or is what SpaceX is doing simply a trial and error aproach in this only? Like, see how many times it works, then investigate and see where to improve.

While you obviously only go to Mars if your willing to die I think it is important to have already active implementations in place in how to identify problems before they cause havoc and how to solve them.
The same maintenance solutions should also still work if you need to re-apply them like on a airplane.

How else are you going to get that desirable price tag? Getting 100people killed IRL is like your reputation slider in KSP drops from max to negative.

Any thoughts, or better yet real intel? We're trying to do something that I think has a higher mortality rate then the Ships that crossed the atlantic in the late 15th century and carry even more people. The price tag Elon talks about is like assuming nothing goes wrong from A,B, to Z.

[Northstar1989]

32 minutes ago, Chabadarl said:

I think he's a little vague about the true raisons but I can cite one persone that is going spend a fortune trying....

 

You mean Musk, right?

Anyways, people miss a key point- Mars is an entire seperate planet with just as much land as Earth! (due to its lack of oceans)

This means that, eventually, it should be able to sustain a significant fraction of Earth's population (Mars also receives similar insolation at the surface, despite its distance from the Sun, due to its lack of atmosphere to reflect or absorb light- so there's also a similar amount of renewable energy available compared to Earth).  Eventually, Mars could sustain BILLIONS of people.

I think most people miss the massive economic benefit that would provide to Earth.  Even if hard goods are never economical to transport back to Earth, there is nothing to stop the transfer/trade of intellectual property.  When Mars,is a thriving world millions strong, it will generate software, media, and scientific research that will all benefit Earth- and since the colonies will eventually become self-sufficient, this won't come at any actual cost to Earth other than the IP we trade in return.

THAT is the main economic reason to colonize Mars.  In the short run, it will generate hope, innovation, and strengthen either America's leadership or global unity (depending on whether it ends up receiving more US or UN financual support).  In the long run, it increases humanity's sustainable population limit by providing us the carrying capacity (this is an ecological term every competent biologist is taught- basically it means the maximum sustainable population of an area) of an entire second planet to live on, and should generate immense trade of knowledge, engineering, software and media!

 

Regards,

Northstar

P.S.  If I relate everything back to biology, that's because I'm a biologist in real life, if you hadn't guessed by now...  Biology, like physics, is particularly unique in that it teaches you how to think about problems in a fundamentally different manner.  In a way, I have something in common with Elon Musk in that I have advanced education in a scientific discipline that allows me to view the world differently than those around me, and come up with fresh insights.  Sadly, I lack Musk's skills with programming and entrepreneurship (and luck to be born at the right time to take advantage of the .com bubble) that gave him the chance to make his mark with that unique viewpoint...  I may also seem deficient at persuasion- but trust me, I am *far* better at it in person when I wish to be... (I have a proven track record as a highly-skilled and award-winning debater, dealmaker, and political organizer)

Edited October 10, 2016 by Northstar1989

[shynung]

40 minutes ago, Northstar1989 said:

Mars is a destination for passengers.  People will move there in ever greater numbers if there is a colony, and return in large numbers as well.  Like I said before, people are and often were the only profitable cargo.

And why is that? Currently, Mars doesn't have any native inhabitants that wanted to go here, and no colony to speak of. Where is this load of passengers coming from?

Colonists? Musk's concept of sending 100 people in each outbound trip would make only a small-ish town, even smaller if not all of them stays. And there's only one outbound trip every 2 years or so. How long until there's enough colonists so that there are enough people wanting cheaper Mars-bound tickets there, necessitating building the space-railroad infrastructure necessary to achieve that?

40 minutes ago, Northstar1989 said:

(once again, you are ignoring the most important and relevant points in my post in favor of attacking auxiliary points out-of-context)

That means I have no objections to the points I ignored, or I see no need to debate it further. There is nothing malicious in me attacking other points of your argument, it is simply how I discuss and analyze other people's ideas. Me or other people attacking auxiliary points mean there is something weak in them that we wish to probe further, in order to strengthen it or replace it with a stronger idea.

24 minutes ago, Northstar1989 said:

Anyways, people miss a key point- Mars is an entire seperate planet withjust as much land as Earth! (due to its lack of oceans)

This means that, eventually, it should be able to sustain a significant fraction of Earth's population (Mars also receives similar insolation at the surface, despite its distance from the Sun, due to its lack of atmosphere to reflect or absorb light- so there's also a similar amount of renewable energy available compared to Earth).  Eventually, Mars could systain BILLIONS of people.

Ah, the Lebensraum argument.

Here's our situation. The living conditions in almost every landmass on Earth is much better than that of Mars (remember, Mars has no breathable atmosphere, or a planetary magnetic field). As you can see, our planet isn't currently overcrowded with humans yet, so there is no immediate need to ship people off-planet efficiently en masse. Your colonization architecture comprising of cyclers and dedicated cargo ships seemed to suggest that it is best used to ship people off-planet efficiently en masse. Why should we build upon your architecture?

Edited October 10, 2016 by shynung

[Northstar1989]

28 minutes ago, shynung said:

Ah, the Lebensraum argument.

Here's our situation. The living conditions in almost every landmass on Earth is much better than that of Mars (remember, Mars has no breathable atmosphere, or a planetary magnetic field). As you can see, our planet isn't currently overcrowded with humans yet, so there is no immediate need to ship people off-planet efficiently en masse. Your colonization architecture comprising of cyclers and dedicated cargo ships seemed to suggest that it is best used to ship people off-planet efficiently en masse. Why should we build upon your architecture

It's not about space, it's about *Carrying Capacity*.  Those ywo things are entirely different, as any biologist can tell you...

Carrying Capacity is about a variety of things, including the availability of food and other resources.  Almost none of the planet, except the parts covered by snow most of the year, or inhospitable desert (and with desalinization of seawater and irrigation of the desert to grow crops on a massive scale in the wealthier desert nations like Israel, even THAT is starting to change), is actually empty.

Almost all of the planwt is utilized for some economic purpose- be it seal-hunting, seasonal grazing of camels during the rainy season in semiarid deserts, lumber-sourcing, mining, or most important of all for population limits- farming.  Only the most marginal areas see no economic utilization at all- and even that is only because the planet hasn't reached a sufficuent level of global economic development to incentivize reclamation of such land (political instability often prevents foreign investment from accelerating this).

It's also worth noting that the Carrying Capacity of the planet is the MAXIMUM # of people it can sustain.  As in, everybody living in extreme poverty to the extent that disease doesn't limit the population levels of resource utilization by killing hundreds of millions in massive plagues (far more likely if people are wretchedly poor due to living close to the limits of other natural resources.  Population-density is also a direct risk factor for the spread of disease).

If people don't choose to have more than replacement levels of children past a certain point, then for all intensive purposes the Carrying Capacity is even less than this.  On the other hand, technology tends to raise the Carrying Capacity for humans- in that it allows us to access and efficiently utilize a larger feaction of the planet's resources (for instance the ability to covert wind-->electricity-->growth lamp power-->underground crops) but there will alwats be limits- for instance the availability of certain rare trchnologically-vital elements...

Eventually, we WILL reach our planet's Carrying Capacity.  We can only feed and clothe so many people with so much land (once again, how densely that land is actually inhabited is irrelevant- less densely populated nations just end up exporting surplus resources to more populoys ones anyways, so the resources still find their way into the global market).  Having an entire additional planet at our disposal means we can comfortably support a much larger population...

 

Regards,

Northstar

Edited October 10, 2016 by Northstar1989

[shynung]

Just now, Northstar1989 said:

It's not about space, it's about *Carrying Capacity*.  Those ywo things are entirely different, as any biologist can tell you...

Then forgive me for being ignorant, for I am not a biologist. Do explain.

[Northstar1989]

16 minutes ago, shynung said:

Then forgive me for being ignorant, for I am not a biologist. Do explain.

See above please.  My answers take so long to write I often post them in segments before my login times out...

EDIT: Answer should be more or less done now.

Edited October 10, 2016 by Northstar1989

[Technical Ben]

8 hours ago, Streetwind said:

Shocked that nobody has corrected this in several days. The whole point of the SpaceX ITS infrastructure is that it is reusable. The entire spacecraft is taking back off and coming back home. And anyone who wants to can fly home along with it. No cycler required.

This isn't news either. Elon Musk has talked about this for about three years now, and reiterated it multiple times during the reveal at IAC.

Ok, I'll take that back then.

I heard lots of "those going to Mars should be willing to die [for it/because it is risky]" and had not heard of any of the return missions from SpaceX  (only from the NASA mission profiles). So thanks, if that is the case, my positivity towards the mission just peaked.

I've managed to get a successful refuel and landing on Duna with a similar mission profile now. If I'd balanced the re-entry better I could have circularised and chosen a landing spot, but currently just aimed straight at it and landed. The key was being more aggressive with the first stage. Though they are doing the opposite for SpaceX IRL, it helps in KSP as no concurrent missions (but I managed the landing of stage 1 and caricaturisation of stage 2! :D).

Docking the big heavy tanker is also a difficulty. But nothing that a few more veneers won't fix.

So now I just need to keep refining the design and flight profile, and try for a quicker transfer if my planning/maths and fuel budget allow it.

Oh, and if it's to return to Kerbin, I'll need to swap out the inflatable heatshield for a plain one... and take a very light entry angle.

Edited October 10, 2016 by Technical Ben

[Northstar1989]

8 minutes ago, Technical Ben said:

Ok, I'll take that back then.

I heard lots of "those going to Mars should be willing to die [for it/because it is risky]" and had not heard of any of the return missions from SpaceX  (only from the NASA mission profiles). So thanks, if that is the case, my positivity towards the mission just peaked.

I've managed to get a successful refuel and landing on Duna with a similar mission profile now. If I'd balanced the re-entry better I could have circularised and chosen a landing spot, but currently just aimed straight at it and landed. The key was being more aggressive with the first stage. Though they are doing the opposite for SpaceX IRL, it helps in KSP as no concurrent missions (but I managed the landing of stage 1 and caricaturisation of stage 2! :D).

Docking the big heavy tanker is also a difficulty. But nothing that a few more veneers won't fix.

So now I just need to keep refining the design and flight profile, and try for a quicker transfer if my planning/maths and fuel budget allow it.

Stock KSP is nothing like real life in its balance, sadly.  I would strongly recommend trying to re-create the ITS infrastructure in RSS 64k with RealFuels installed to get a better feel for it.  Even then, there are serious problems with the mass-size relationships of things like the Mk3 parts (almost all the parts in KSP are much, much, much heavier than they should be for their size.  And the fuel is far too dense as well.  And the parts are a fraction the size of their real-life counterparts.  All of which means you won't get the right performance for a rocket that 'looks" right, and trying to replicate real life craft in stock is *very* hit-or-miss...)

 

Regards,

Northstar

Edited October 10, 2016 by Northstar1989

[magnemoe]

18 minutes ago, Northstar1989 said:

See above please.  My answers take so long to write I often post them in segments before my login times out...

Carrying capacity works well for animals. How many sheep can grass this field or how many moose do we want in the forest. it was relevant for humans at least up to civilization. With high capacity and cheap transport its pointless outside an global scale. Cities has always had far more people than its carrying capacity, as an balance farmland has far lower population than its carrying capacity.
Yes popularity density is related to ecology but lots of that is historical and that people don't want to live in wastelands. 

[Technical Ben]

Yeah. My RAM exploded (literally, I fixed that stick [literally], but the other one it took out in the process did not survive) and so I'm down to 4gb RAM and sticking to stock KSP until 1.2 rolls in and might try RSS and a few others once I get this PC up and running better. Would love a procedural parts and some of the SpaceX mods on a RSS play through. Though creative always catches my focus.

But back on topic, it was as an exploration of the mission profile, pit falls, requirements and alternative options (such as cyclers, which I will check out). All of which are quicker (I guess?) in KSP scales.

Things like "Do I scavenge the lander as a habitat, or launch it back and send separate habitats?" came from playing, even though it is just a game. So I'd wonder if Musk would dig out habitats, or if a "cheaper" lander is worth the resource savings on sending separate habitats? I'd assume inflatable habitats would always be cheaper.

[shynung]

1 hour ago, Northstar1989 said:

It's not about space, it's about *Carrying Capacity*.  Those ywo things are entirely different, as any biologist can tell you...

Carrying Capacity is about a variety of things, including the availability of food and other resources.  Almost none of the planet, except the parts covered by snow most of the year, or inhospitable desert (and with desalinization of seawater and irrigation of the desert to grow crops on a massive scale in the wealthier desert nations like Israel, even THAT is starting to change), is actually empty.  Almost all of it is utilized for some economic purpose- be it seal-hunting, seasonal grazing of camels during the rainy season in semiarid deserts, lumber-sourcing, mining, or most important of all fir population limits- farming.

I think this is something we can engineer to a degree. Genetic engineering can create fast-growing crops and trees, geoengineering can make previously inhospitable areas inhabitable, and various technologies can improve our resource extraction capabilities. In short, we can intensify the processes the we require to get resources enough so that a smaller area can feed a bigger population than it was before.

On the other hand, Mars doesn't have the resources we are used to collect from our surroundings. Contrary to popular belief, Mars has no arable land, nothing to plant crops on. There are no easily accessible water on the surface; one must look for water by drilling a well, which takes time and energy. And more importantly, it doesn't have a breathable atmosphere, nor does it have a planetary magnetic field to protect its inhabitants from space radiation. The atmosphere is also very thin, which means there are little protection from incoming projectiles; falling space rocks are a dime a dozen. Compared to Earth, Mars have little to no Carrying Capacity to speak of; we'd have to build infrastructure to expand it ourselves.

And here's the kicker: anything we invent to give Mars some Carrying Capacity would be usable here. Using technology initially earmarked for colonizing Mars would make the hottest of deserts habitable. Efficient soil-less farming techniques would enable agriculture in even the harshest environments on Earth, opening more areas for settlement. Efficient water extraction, processing, and recycling technologies would help sustain cities that have limited water supplies, and so on.

In short, whatever we do to make living on Mars possible, it would improve our own planet's Carrying Capacity further. And we don't have to haul our carcasses all the way to another planet to get these benefits.

Now, if our goal of shipping people to Mars was to set up an outpost, say, for scientific research, then it starts to make sense. There are some knowledge that we can't acquire by any way other than spending some time living on Mars. This might be something like knowing environment characteristics, accurate data on resource location and richness, and some other things This knowledge may later help us colonize Mars, when we can't stretch Earth's Carrying Capacity any more.

For this purpose, building a space-railroad to Mars is unnecessarily expensive if a simpler, cheaper vehicle can do the job. Only after significant surface presence is established can we justify spending more to develop additional infrastructure to act as space-railroads.

Edited October 10, 2016 by shynung

[mikegarrison]

One thing is for sure, being in that crew capsule during a LES event would be an e-ticket ride.

[kerbiloid]

2 hours ago, magnemoe said:

Space is cold,

Space is different. -100 at night side, +100 under Sun.
Also, any ship produces waste heat, and cryotanks are just a part of its construction, not isolated.
So, cryotanks usually last for hours, Buran with its special countermeasures was designed to keep LOx up to a month, long living crafts use hypergolics.

[magnemoe]

16 minutes ago, kerbiloid said:

Space is different. -100 at night side, +100 under Sun.
Also, any ship produces waste heat, and cryotanks are just a part of its construction, not isolated.
So, cryotanks usually last for hours, Buran with its special countermeasures was designed to keep LOx up to a month, long living crafts use hypergolics.

So you shade the sun and has -100, as stated many times in this discussion the SpaceX mars ship and  buran is not designed to for this as both has to keep tanks inside airframe, an classical IIS style long truss ship would have no issues insulating the tanks, yes most of this designs used nerva and hydrogen where cooling is far harder and you needed active cooling anyway. 
No idea how to do this with something having to aerobrake.  

[_Augustus_]

43 minutes ago, kerbiloid said:

So, cryotanks usually last for hours, long living crafts use hypergolics.

How does a BNTR Mars Transfer Vehicle work then? Wouldn't the propellant all boil off?

[SargeRho]

1 hour ago, _Augustus_ said:

How does a BNTR Mars Transfer Vehicle work then? Wouldn't the propellant all boil off?

Part of the Bimodal NTRs' power would be used to power cryo-cooling systems.

[DerekL1963]

2 hours ago, mikegarrison said:

One thing is for sure, being in that crew capsule during a LES event would be an e-ticket ride.

A friend who worked as engineer for NASA out at Dryden used to describe ejection seats thusly:  "Attempting suicide to avoid certain death".   I imagine LES systems are much the same thing.

[kunok]

8 hours ago, Streetwind said:

The amount carried by the tanker does not fundamentally change anything about a known process. It's a plumbing engineering issue, nothing more.

The bigger issue here is getting the fuel systems of the spacecraft as a whole to work the way they want. In my (admittedly amateurish) opinion, the act of moving liquids between two spacecraft is a mere footnote to the challenges of designing a cryogenics-capable, actively refrigerated carbon-composite tank that survives ten years of repeated filling and emptying in three different environmental conditions... and on that absurd scale, no less! I think it's quite indicative that SpaceX has decided to get a head start on exactly that.

Serious question: did spaceX ever made a orbital refueling operation? I don't recall that.

[PB666]

6 hours ago, shynung said:

Then forgive me for being ignorant, for I am not a biologist. Do explain.

Space is infinitely populable, yes this does sound rediculous, but its a statement that has to be heavily conditioned.

Human body is composed of mostly Oxygen, Hydrogen, Carbon, Calcium, Nitrogen, etc. There is more than enough free floating around betweeen the Heliopause and Earths orbit to increase the human population 1000 fold. So resources per say is not the problem. The problem is facilitating the expansion of humans. There are several legistical hurdles.

1 Accommodating the biology

  a. Pressure requirements (pO2, pN2, p
  b. Homeostatic temperature requirements.
  c. Pressurized volume requirements.
  d. Relative Acceleration requirements (as in gravity or centripedal acceleration)
  e. Nutrient requirements.

2. Dealing with space.

  a. Radioactivity. and cosmic radiation
  b. Efficient transport systems (how to get a resource from say kuiper belt to where humans are)
  c. Nonconsolodated energy sources. Unfortunately on earth energy is consolidated at high density, e.g. Coal reserves, oil reserves. Were basically we talk in terms of 100s of kCal per liter/kg of energy. Energy in space declines, with abundance at k/d^2 from the sun, This is because nuclear energy in space in support of humans is not feasable at that moment, Fossil fuels have too low of energy density and transporting fossil fuels from 1 AU too where resources are abundant is an extremely inefficient way of reaching those resources.

Abstractly, stars, largely composed of hydrogen and other light elements explode sending bits and pieces flying away at the speed of light, very much faster than the energy we need to get from the inner solar system to the outer (something like 10 m/s) and back again. The problem is that the means we have to generate that level of mass efficiency is incredibly catastrophic in its consequences. Therefore we need to come up with nuclear methods that are better. If we can do this we can have colonies in space or on distant planets.

As stated previously ION drives have no effective limit on ISP literatlly they can deliver 30,000,000 sec. The problem is for a 30,000,000 sec drive your are 300MW per newton. And your typical solar panel is producing 1KW per 3 meters. So we are off really by a factor of 10,000 between what we can efficiently produce and what we might need to travel around space grabbing resources at our liberty. In additional panels only make sense in the inner solar system. So essentially nuclear power is not a luxury, its a requirement of resource exploitation in space. 

Mars is not out of the question with an adequate power supply, but the problem is trying to set up a colony on Mars without such a power supply is nothing less than suicide.

Its cart before the horse.

 

 

On the issue of Space X refueling and transport systems

1st. Space does not feel hot or cold. You are either net radiator or absorbed of solar energy. On the outward facing side and shielded from the sun and from radiation from the ship one can develop temperatures a few degrees above kelvin. On the sun facing side, depending on the material you can reach smelt furnace temperatures. So managing temperature is all about guidance and engineering. On the messenger mission they folded solar panels as to reduce the incident angle of the sun relative to the panel. Solar panels can also be used a shields. Theoretically if you traveled at the speed of the solar wind and 100% reflection of sunlight you have a temperature of about 3'K.

2nd. Its not impossible to engineer a nearly passive cryogenic fuel storage system as part of a transporter.

3rd. I should mention that if you wanted to transport millions of people to Mars, that a slow transporter such as Mg ION drive in which the propellant is a solid wire that can be fed into a solar driven drive is the most efficient and needs no cryogenic. You might take 5 years to transport to mars but again if you are transporting facilities and supplies for millions, you only need fast transport for the living, not the non-living materials (which will be the overwhelming majority of mass used to provide for the colony). Given the higher requirements of reaching Mars in terms of mass dedicated to solar panels (and in particular going back to earth) that occupation is in search of lighter weight and more efficient panels, capable of generating several MW of power.

As stated in my previous post, without nuclear such a colony is untenable. On mars with current technology you get about 100 watt per meter of solar panel (not factoring dust), this is not adequate to run an ISRU to make fuel, provide power for probably buried greenhouse for LEDs and heating, let alone essential life support on the surface.

To get a viable subterranean colony you need drills and equipment that used 100s of KW as part of standard operation (soil and rock excavation), tunneling equipment, etc. We are nowhere near getting a viable power supply for these things. Our deep space power supplies are about 300 to 500 watts once broken in, and from another post, there is only enough nuclear fuel left for one of these. This does not mean you need 10 football fields of panels, but at least you need massive amounts of Li ion batteries capable of burst in the KW to MW range.

The problem is not obscure, the problem is energy, whats their source.

 

[kerbiloid]

9 hours ago, _Augustus_ said:

How does a BNTR Mars Transfer Vehicle work then?

I'm sorry, I've forgotten, when it had been launched the last time?

9 hours ago, magnemoe said:

So you shade the sun and has -100, as stated many times in this discussion the SpaceX mars ship and  buran is not designed to for this as both has to keep tanks inside airframe

Shade = keeping inside, am I wrong? A shadow screen shades not only from outside (from the Sun radiation), but also from inside (from the ship radiation).
Say, ISS is.not very much powered (in comparison with a ship of similar mass), but it has multiple radiators. So, one should put the screen right below red hot radiators.

[Streetwind]

9 hours ago, kunok said:

Serious question: did spaceX ever made a orbital refueling operation? I don't recall that.

Cargo Dragon carries water in internal tanks, which is pumped into tanks on the ISS.

It's not strictly speaking refueling, I know But it's the closest thing they've done. And it does show that they've designed and built a working zero-G liquid pump and plumbing mechanism.over six years ago. That's a lot of time to expand to other, less benign liquids in that area of expertise, even if it's only looking up and simulating stuff other people have done. (That Space Act Agreement with NASA, which gives them unlimited access to all of NASA's research and operational data, isn't just for show after all.)

Edited October 11, 2016 by Streetwind

[StarStreak2109]

10 hours ago, DerekL1963 said:

A friend who worked as engineer for NASA out at Dryden used to describe ejection seats thusly:  "Attempting suicide to avoid certain death".   I imagine LES systems are much the same thing.

That reminds me of the anecdote Scott Manley mentioned talking about the one time a Soyuz capsule triggered an escape, leading to the kosmonauts suffering 14gs, which in  turn lead to extensive use of un-family-friendly words by said kosmonauts... I mean, it is good that such systems exist, but I guess every astro/kosmonaut hopes he'll never have to experience this...

[Nefrums]

The ITS is obviously designed to travel with engines facing the sun.

• Engine section is designed to handle high temperatures
• No direct sunlight on the fuel tanks.
• The entire craft acts as radiation shield for the crew section.

[kunok]

2 hours ago, Streetwind said:

Cargo Dragon carries water in internal tanks, which is pumped into tanks on the ISS.

It's not strictly speaking refueling, I know But it's the closest thing they've done. And it does show that they've designed and built a working zero-G liquid pump and plumbing mechanism.over six years ago. That's a lot of time to expand to other, less benign liquids in that area of expertise, even if it's only looking up and simulating stuff other people have done. (That Space Act Agreement with NASA, which gives them unlimited access to all of NASA's research and operational data, isn't just for show after all.)

Yeah but did ever nasa done a refueling operation? An automated one?