SpaceX Interplanetary Transport System (updates)


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Unobscured Vision

Yep. We don't know the weight comparison relative to a metal-fabricated one, but it's a sure bet that it'll be on the order of 1/5 ~ 1/8th as heavy. Especially since SpaceX doesn't use baffles, helping the weight even more. These tanks will be the most advanced ever built. Hell, this whole Spacecraft will be the most advanced thing to ever fly -- Air or Space. And we thought Dragon 2 was some slick #### ... wait till ITS has a Demo Flight. We'll think we've gone to Nerd Heaven. :yes: 

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FloatingFatMan

To top it all, that compressed carbon fibre, when applied to aeroframes, might well make Musks dream of an electric jetliner possible thanks to the much lower thrust to weight ratio...

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DocM

Exactly. These composites are nothing less than game changing. 

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FloatingFatMan

Use it for vehicle frames too, which will reduce the weight of Musk's Tesla's even more...

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DocM

Too rigid. Vehicles need the materials ton progressively crush like metals for crash protection. Aerospace grade aluminum is just fine.

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Unobscured Vision
1 hour ago, FloatingFatMan said:

Use it for vehicle frames too, which will reduce the weight of Musk's Tesla's even more...

 

1 hour ago, DocM said:

Too rigid. Vehicles need the materials ton progressively crush like metals for crash protection. Aerospace grade aluminum is just fine.

That's what my brother and I were discussing. They're great for Aerospace use (Aircraft, Spacecraft, etc) after everyone does recalculations and "learns how to fly again", but not so good for Cars. We need those superstructures to give, for safety reasons, in impacts. Those forces have to be absorbed and dissipated in and at the materials rather than our bodies. Better that a frame absorb it and then snap in half than a human spine. :yes:

 

There's still a use for metals, don't get me wrong. LOTS of uses. Just we'll use a lot less of them, and the weight & fuels savings will be a boon to all sectors of Environmental Concerns, Commerce and Industry. And the Jobs -- and the Education, Industry Infrastructure and Ecosystems needed to support all of that -- will be big business ten years from now.

 

Oh, and now with the advent of ISRU Technologies, especially the new discovery of that "Easy Ethanol from CO2" process (with a 60% efficiency yield!) ... keep TWO Ethanol (CH3+CH3) from this process (store it, break it down, or convert as below; whatever), use the "extra" stuff you're getting from it and you've got H2O plus Nitrogen now. You're now removing all of this CO2 from Earth's Environment that everyone is crying about -- Planet saved and we've now got fuel. Apply some "easy chemistry" and turn that Ethanol into Methanol (CH3-OH).

 

As a sidenote -- Methanol should probably be converted into Methane (CH4) if we wanna store it for later .. way safer. Another discussion for another thread, VAST number of uses here too. :yes:

 

They're just getting started with the Composites Industry. :D Gonna be huge. HUUUUUUGE. Can't wait.

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FloatingFatMan

No, the crumple zones need to remain as metal yes, but the cage part around the passenger area, inside the crumple zones, that needs to withstand an impact to protect the occupants.

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DocM

That would be OK if the carbon members can take high single point side loads of an accident without shattering. I've been in a racer with steel roll cage and it worked great in a 140 mph oopsie, but there was a helluva dent in each of the tubes at their IP's. Carbon? Show me.

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FloatingFatMan
8 hours ago, DocM said:

That would be OK if the carbon members can take high single point side loads of an accident without shattering. I've been in a racer with steel roll cage and it worked great in a 140 mph oopsie, but there was a helluva dent in each of the tubes at their IP's. Carbon? Show me.

I can't, but perhaps the guys making this stuff can...

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DocM

Motor Sports Assn. standard is a steel roll cage.  Last I checked FIA was similar, with a slight difference wrt the additives. Both require the main tubes to be one piece, including the bends, which makes fabbing carbon on a mandrel an issue.

 

MSA,

 

Material Specifications


1.4.1. Specifications of the tubes used:


Minimum Material


Cold Drawn Seamless Unalloyed Carbon Steel, containing a maximum of 0.3% of carbon. Note: For an unalloyed carbon steel the maximum content of additives is 1.7% for manganese and 0.6% for other elements.

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  • 2 weeks later...
DocM

And how big is the ITS spaceship in historical terms?

 

Click the imgur link for the full size 4k image.

 

 

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FloatingFatMan

Sooo... How long before they start construction of the actual ship?

 

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DocM

Their timeline shows very soon, with spaceship "Grasshopper" tests around Q3 of 2018 and orbital tests in 2020.  They're cryo testing the full scale LOX tank and firing the Raptor engine now, and items which can't be discussed.

 

They're also negotiating a deal for ~$2.5-3 billion worth of top-end aerospace composites, and there's a deal for advanced radiation tolerant semiconductor wafers.

 

Thiis train has left the station.

 

Timeline

ITS-Timeline-1280.jpg

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anthdci

this wont be a way for this to dock with the ISS will there? I'm sure I saw a photo of it next to the ISS and it was huge. I'm sure sure if there is any point, more of a hypothetical.

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Unobscured Vision

Not until/unless the ISS gets some additional modules designed for that purpose. Right now there's no talk of them, so that'll be a tentative "nope".

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patseguin

Not sure why they call it the interplanetary transport. I guess technically if it goes to Mars it could be called that. Our tech is pretty prohibitive for the years' journeys to the other planets.

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Unobscured Vision
Just now, patseguin said:

Not sure why they call it the interplanetary transport. I guess technically if it goes to Mars it could be called that. Our tech is pretty prohibitive for the years' journeys to the other planets.

Because it can pretty much go anywhere up to and including Saturnian Space. That is the limits of the technology, currently. Saturn. :yes: Whether Humans can deal with the journey? That remains to be seen. I'd say yes, but it'd be difficult.

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DocM
46 minutes ago, patseguin said:

Not sure why they call it the interplanetary transport. I guess technically if it goes to Mars it could be called that. Our tech is pretty prohibitive for the years' journeys to the other planets.

It's designed primarily to carry up to 100 people and up to 450 tonnes of cargo to Mars and return. Use fewer crew, less cargo and preposition propellant depots (or propellant "factories" using indigenous resources) and it could go about anywhere in the solar system. It's also going to be FAST - this spaceship will have a max thrust of over 5 million pound-force, 21+ meganewtons, in a vacuum. Musk has also discussed adding plasma engines down the road.

 

There have also been major recent advances in life support systems, water processing etc.

 

Yeah, interplanetary. As in the Moon, Mars & it's moons, Ceres, the outer Jovian moons, Saturn's moon Titan etc.

Edited by DocM
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robertwnielsen
30 minutes ago, DocM said:

It's designed primarily to carry up to 100 people and up to 450 tonnes of cargo to Mars and return. Use fewer crew, less cargo and preposition propellant depots (or propellant "factories" using indigenous resources) and it could go about anywhere in the solar system. It's also going to be FAST - this spaceship will have a max thrust of over 5 million pound-force, 21+ meganewtons, in a vacuum. Musk has also discussed adding plasma engines down the road.

 

There have also been major recent advances in life support systems, water processing etc.

 

Yeah, interplanetary. As in the Moon, Mars & it's moons, Ceres, the outer Jovian moons, Saturn's moon Titan etc.

So, the max thrust won't be as much as the Saturn V of the old Apollo program? (7.5 million pounds of thrust)

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Unobscured Vision
20 minutes ago, robertwnielsen said:

So, the max thrust won't be as much as the Saturn V of the old Apollo program? (7.5 million pounds of thrust)

The thrust quoted is the upper stage -- the business end. Lower stage is gonna be upwards of 13~18 million, or more depending on payload and destination requirements.

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robertwnielsen
2 minutes ago, Unobscured Vision said:

The thrust quoted is the upper stage -- the business end. Lower stage is gonna be upwards of 13~18 million, or more depending on payload and destination requirements.

Ah. I wonder how much G-force that kind of thrust will generate?

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Unobscured Vision
8 minutes ago, robertwnielsen said:

Ah. I wonder how much G-force that kind of thrust will generate?

They'd control the thrust to limit it to 3g at launch, maximum. That's for Crew Safety. For Cargo Missions, likely 4g's.

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robertwnielsen
1 minute ago, Unobscured Vision said:

They'd control the thrust to limit it to 3g at launch, maximum. That's for Crew Safety. For Cargo Missions, likely 4g's.

IIRC, the shuttle generated about 3g at maximum, so that would make sense. Although, 4g wouldn't be terrible, for humans. A little uncomfortable, I would imagine, but easily survivable.

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DocM
1 hour ago, patseguin said:

 

 

33 minutes ago, Unobscured Vision said:

The thrust quoted is the upper stage -- the business end. Lower stage is gonna be upwards of 13~18 million, or more depending on payload and destination requirements.

No. The ITS Booster has 42 Raptor engines, for a liftoff thrust of about 29 million pound-force (128 meganewtons) of sea level thrust. Saturn V was 7.891 million pound-force (35.1 meganewtons)

 

The ITS Booster is a beast.

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Unobscured Vision

Yep, excuse me. 29 million. I lowballed it by 50%. My bad.

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