Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD

[envy887]

Well, I ask given that the answer seems to suggest that the Raptor needs another system to run in in order to "retire the risk" as you say.  You're right, of course, that the recent failures force me to set the bar a little higher than "trust SX", but the thrust of my point was to wonder what that other system is....

Well Like Elon said the engine is the same physical size of the Merlin engine, and the USAF is paying them to develop an upperstage engine for Falcon through Raptor.....

Need not be "either or". We heard Raptor Vac has a 14 foot (3.66M) nozzle, might it fit as a payload in the 5M shroud? You could test it as an in-space stage that way, using two F9US Oxygen tanks (with GHe pressurization) ... and get performance/validation w/o building an entire US ...

Then if AF wants to commit to a Raptor US of some sort they'll have it. Perhaps alongside funded BO/ULA US?

Merlin Vac was tested (failing restart first time) in flight, as there was no vacuum test stand test.

All AF did was encourage US engine development with cofunding to various efforts, including SX. Nothing more.

The fact that AF has seen the engine built and fired on a test stand likely exceeds requirements, as they will have gotten the test data that they desired. (Many similar programs don't even get that far.)

Rvac was listed in the presentation slides as having a 3.85m nozzle, which is less than 14 feet but bigger than the Falcon interstage.

However, there's no reason they can't trim that down to ~3m like the Mvac and still get about 375 seconds of ISP. The SL nozzle is 1.75m and gets something like 365 seconds. Huge improvement over Mvac on FH.

[RoboGoofers]

regarding cargo and offloading:

I'm sure the cargo will be in standard modules, like shipping containers. I assume that the containers will either be repurposed for living quarters or could be assembled into structures or equipment.

offloading wouldn't require much more than a hoist, 5 people and a week (probably less). I'm not sure why some here think it needed to be explained in detail in this presentation.

[Ludus]

If you are putting 1000 ships in LEO - than that means 4000-5000 fuel launches!.   That is a lot of course - but it seems wasteful.   If we can make methane on Mars, would it be more efficient to make it there and send it back to LEO (with most efficient and slow transit) in advance?   If we could make it on the moon that would be a no-brainer, but not sure if that is possible.

Certainly you can get the O2 from the Moon; it's abundant there.

Methane is apparently also possible, but would require serious effort — it's present in only trace amounts.

Musk did mention at one point that he considers a lunar fuel depot to be a "future optimization."  I take that as, if somebody builds it and it works out cheaper/better for him, he'll be happy to buy their fuel.

ISRU for Methane like on Mars wouldn't be about trying to find it, it would be about synthesizing it from Hydrogen and Carbon. The Hydrogen and Oxygen come from water ice, on the moon the problem is Carbon. There are possible sources but it awaits further exploration. On Mars it's easy to get it from the atmosphere.

[Space Ghost 1962]

Well, I ask given that the answer seems to suggest that the Raptor needs another system to run in in order to "retire the risk" as you say.  You're right, of course, that the recent failures force me to set the bar a little higher than "trust SX", but the thrust of my point was to wonder what that other system is....

Well Like Elon said the engine is the same physical size of the Merlin engine, and the USAF is paying them to develop an upperstage engine for Falcon through Raptor.....

Need not be "either or". We heard Raptor Vac has a 14 foot (3.66M) nozzle, might it fit as a payload in the 5M shroud? You could test it as an in-space stage that way, using two F9US Oxygen tanks (with GHe pressurization) ... and get performance/validation w/o building an entire US ...

Then if AF wants to commit to a Raptor US of some sort they'll have it. Perhaps alongside funded BO/ULA US?

Merlin Vac was tested (failing restart first time) in flight, as there was no vacuum test stand test.

All AF did was encourage US engine development with cofunding to various efforts, including SX. Nothing more.

The fact that AF has seen the engine built and fired on a test stand likely exceeds requirements, as they will have gotten the test data that they desired. (Many similar programs don't even get that far.)

Rvac was listed in the presentation slides as having a 3.85m nozzle, which is less than 14 feet but bigger than the Falcon interstage.

However, there's no reason they can't trim that down to ~3m like the Mvac and still get about 375 seconds of ISP. The SL nozzle is 1.75m and gets something like 365 seconds. Huge improvement over Mvac on FH.

Too much of a distraction. Too many projects.

Musk clearly wants the ICT next. And can fly/prove it suborbitally. That's the one to focus on. While settling F9.

[M.E.T.]

regarding cargo and offloading:

I'm sure the cargo will be in standard modules, like shipping containers. I assume that the containers will either be repurposed for living quarters or could be assembled into structures or equipment.

offloading wouldn't require much more than a hoist, 5 people and a week (probably less). I'm not sure why some here think it needed to be explained in detail in this presentation.

But given that the concept involves some substantial unmanned operations - including the production of propellant on Mars - before any humans arrive, unloading such large pieces of equipment from the top of the landed spaceship seems like a bit of a challenge at this stage.

So you send a bulldozer and some chemical factories ahead without any humans on board. How do you get them down to the surface?

[sanman]

http://www.green4sea.com/wilhelmsen-sets-new-standard-for-boil-off-rate/

Wilhelmsen Technical Solutions (WTS) passed a milestone by successfully completing the gas trial for the first LNG carrier built to a Boil Off Rate (BOR) of 0.08% per day.

So about 30% over an 8 month trip.

Why can't boil off be recompressed, chilled, and put back in the the store?

Anyway, I don't think it's practical to ship methane from Mars to Earth Orbit. I would suggest manufacturing it (or kerosene) on Phobos, and using that for a round trip to High Earth Orbit and back to Phobos.

However, Musk is not seemingly interested in Phobos.

Graphene composites might seem like exotic vaporware, but it's got a lot of potential for impermeability against hydrogen and other light volatiles, in addition to high strength.

[billh]

Autogenous pressurization for a subcooled propellant seems thermodynamically dicey. It would require that the vapor and the liquid not be in thermal equilibrium. How's that going to work? You can't inject the gas into the liquid - it would cool and condense. If the vehicle is thrusting (or on the ground) the liquid and gas would separate. At that point you may be able to inject enough hot gas at the top of the vessel to stay ahead of the cooling, but you would also be pumping heat into your subcooled propellant. Maybe this has been covered on another thread? I just don't get it.

[sanman]

But given that the concept involves some substantial unmanned operations - including the production of propellant on Mars - before any humans arrive, unloading such large pieces of equipment from the top of the landed spaceship seems like a bit of a challenge at this stage.

So you send a bulldozer and some chemical factories ahead without any humans on board. How do you get them down to the surface?

Meh, compared to SkyCrane, it would be a piece of cake.

[envy887]

I'd also like to see what kind of docking system they plan to use. In the video, the ITS and the tanker seem to be docked side by side, but that makes no sense, because of the 3-fin geometry and because the underside is a (supposedly flat) heatshield. There seems to be some fishy 3D clipping in that shot.
...

Look at the bottom view of the ship. 2 ships can touch at the 12m diameter without touching the chines/fins. It does look strange in 3D, but do the geometry on the cross-section and it works.

Actually, if each ship has docking adapters on each side, 6 of them could mate in a full circle with the heatshields pointed out. Talk about a giant space station / orbital depot!

[Ludus]

Yes, it seems to me to be a new class of spaceflight vehicle:  it is a sort of integrated second-stage and spacecraft rolled into one.  Not something we've seen much of (if any) before.

Oh and I forgot, Space Shuttle Orbiter.   Over 100 launches and reusable.

Would argue it completes the Orbiter's vision (Faget's). In many, many ways.

Musk isn't doing anything new - shouldn't and doesn't need to do. He's attempting to refactor things stultified by lack of vision. Perhaps this might go a bit further.

It's a lot like doing the shuttle system right. Fully and rapidly reusable. Lifting body for aerobraking but vertical landing so it doesn't need a runway and can land anywhere. Configurable for Tanker, Cargo or passenger versions. Mass produced continuously like an airliner to raise reliability and iteration and lower costs. 10:1 ratio SpaceShips to Boosters built rather than a few handcrafted Spaceships. Fully automated so no need of crew for cargo or Tanker. It is an actual general purpose Space Transportation System but that name was taken.

[TripD]

I flat out don't believe that this thing will land on an unprepared surface without shot-peening its engines to death.

I'm thinking that, until concrete pads can be constructed, one possible option would be to have a rover deploy something like the PSP (pierced steel planking, also known as "Marsden Mattings") landing mats used for helicopters and Harrier jets in forward-deployed locations. However, something lighter in weight than steel, interlocking, and also without the holes in PSP. Maybe this rover and the planking could be delivered by a Red Dragon, provided that the hatch was made large enough for the rover to get out.

This could cover up the sand and pebbles so that they aren't propelled up into the spaceship. Perhaps the same rover could pick up and relocate any medium sized rocks in the chosen LZ.

All of this assumes that the craft will be accurate enough in landing to put it to use.

[Llian Rhydderch]

regarding cargo and offloading:

I'm sure the cargo will be in standard modules, like shipping containers. I assume that the containers will either be repurposed for living quarters or could be assembled into structures or equipment.

offloading wouldn't require much more than a hoist, 5 people and a week (probably less). I'm not sure why some here think it needed to be explained in detail in this presentation.

But given that the concept involves some substantial unmanned operations - including the production of propellant on Mars - before any humans arrive, unloading such large pieces of equipment from the top of the landed spaceship seems like a bit of a challenge at this stage.

So you send a bulldozer and some chemical factories ahead without any humans on board. How do you get them down to the surface?

Now that we have reasonably detailed high-level design images and a few specs, I anxiously await the creative engineers at NASASpaceFlight turning them into passable CAD models and then developing scads of crazy ideas and images of what might fit as cargo in cargo-versions of the ITS Spaceship.   

[Cherokee43v6]

regarding cargo and offloading:

I'm sure the cargo will be in standard modules, like shipping containers. I assume that the containers will either be repurposed for living quarters or could be assembled into structures or equipment.

offloading wouldn't require much more than a hoist, 5 people and a week (probably less). I'm not sure why some here think it needed to be explained in detail in this presentation.

Because the presentation was about creating a Mars Colony transportation infrastructure.  That infrastructure is intended for the development of a permanent habitation on Mars.  In order to develop that habitation, you're going to need cargo that far exceeds the size and weight that can be shifted through a cargo hatch on the 100 person spacecraft and dropped 30+ feet to the ground.

The specific example referenced in my original question was 'heavy construction equipment'.  Something that will be mandatory for site prep and development of the permanent colony.

https://en.wikipedia.org/wiki/Caterpillar_D11

[envy887]

I flat out don't believe that this thing will land on an unprepared surface without shot-peening its engines to death.

I'm thinking that, until concrete pads can be constructed, one possible option would be to have a rover deploy something like the PSP (pierced steel planking, also known as "Marsden Mattings") landing mats used for helicopters and Harrier jets in forward-deployed locations. However, something lighter in weight than steel, interlocking, and also without the holes in PSP. Maybe this rover and the planking could be delivered by a Red Dragon, provided that the hatch was made large enough for the rover to get out.

This could cover up the sand and pebbles so that they aren't propelled up into the spaceship. Perhaps the same rover could pick up and relocate any medium sized rocks in the chosen LZ.

All of this assumes that the craft will be accurate enough in landing to put it to use.

Once assets are on the ground, it will be. Plus, the takeoff thrust is ~10x worse than the landing thrust.

[Space Ghost 1962]

If you are putting 1000 ships in LEO - than that means 4000-5000 fuel launches!.   That is a lot of course - but it seems wasteful.   If we can make methane on Mars, would it be more efficient to make it there and send it back to LEO (with most efficient and slow transit) in advance?   If we could make it on the moon that would be a no-brainer, but not sure if that is possible.

Certainly you can get the O2 from the Moon; it's abundant there.

Methane is apparently also possible, but would require serious effort — it's present in only trace amounts.

Musk did mention at one point that he considers a lunar fuel depot to be a "future optimization."  I take that as, if somebody builds it and it works out cheaper/better for him, he'll be happy to buy their fuel.

ISRU for Methane like on Mars wouldn't be about trying to find it, it would be about synthesizing it from Hydrogen and Carbon. The Hydrogen and Oxygen come from water ice, on the moon the problem is Carbon. There are possible sources but it awaits further exploration. On Mars it's easy to get it from the atmosphere.

The issues with ISRU are about mass effective flows of assayable "mined" product in form usable by a scaleable robotic processing plant that can end-end supply propellant to tankage that won't  wreck plant/feeds/tankage/engines.

In short there is too little known to make practical decisions on building a real plant.

And no, going to another solar system body doesn't help, just changes the problem.

[envy887]

Rvac was listed in the presentation slides as having a 3.85m nozzle, which is less than 14 feet but bigger than the Falcon interstage.

However, there's no reason they can't trim that down to ~3m like the Mvac and still get about 375 seconds of ISP. The SL nozzle is 1.75m and gets something like 365 seconds. Huge improvement over Mvac on FH.

Too much of a distraction. Too many projects.

Musk clearly wants the ICT next. And can fly/prove it suborbitally. That's the one to focus on. While settling F9.

Fair enough. But why stop at suborbital? The crewed ship could (barely) make to orbit without a booster, and the tanker could put quite a bit of fuel in it, again without a booster. With a few fueling missions the ship could do a lunar free return test mission at near-Mars entry velocities.

[iamlucky13]

It sounds like its the actual tank for the initial ship that they plan on using for testing.

I'm wondering where they will test it. Hawthorne factory probably not best place for exprerimental LOX tank. Could they transport something that big to more safe place?

Also landing legs don't like sturdy enough to hold fully fueled spaceship, even on mars.

Do we know this tank is in hawthorne?

Where are the toolings for it?  It could not have been transported in by road.

Maybe SpaceX has another facility somewhere?

Do we have spies at Michoud?

Food for thought: The faceted internal appearance looks consistent to me with sections of tape or slit tow, rather than woven fibers, all in the same orientation for a given "facet." This suggests to me the halves were done by an automated fiber placement machine, rather than by hand. If they were done by hand, it looks like truly superb workmanship.

NASA is known to have at least one AFP machine for prototype work at Langley. I don't know about Michoud. SpaceX would have to have shipped in a pretty fancy rotating mandre in order to present the work surface of such a large part within reach of a small machine like that. I'm aware of a couple major aerospace parts suppliers around the country with AFP machines of varying sizes who might potentially also have capacity to produce one-off parts on contract.

Has there been any indications SpaceX has invested in automated tape layers or AFP? I was digging around on my own, and all I've found is a 2010 article saying they had not. That was quite a while ago in SpaceX terms:
http://www.compositesworld.com/articles/the-private-space-race

If you want an idea what I'm talking about, there's photos and a video here of a 5.5m carbon fiber tank NASA previously had made by Boeing with a similar robotic AFP machine to the Langley one. Based on this video, it looks like they made a barrel section and both domes, then placed those together in a fixturing mandrel to use the AFP machine to overlay the joints, and I assume further build up the thickness. Similarly, the SpaceX tank appears to be two large half sections joined in the middle.
http://www.nasa.gov/centers/marshall/news/news/releases/2014/14-043.html

[punder]

Maybe he can borrow an idea from the Mars One concept, which is selling TV rights to the whole adventure. I can imagine that raking in billions. Not enough to fund it all, but a nice contribution nevertheless.

You got to feel sorry for Mars One now, if they had just kept their powder dry until now they could have designed to the capabilities and cost that Musk outlined and if anyone tried to give them any beef about it they could just point to Elon and say it's on him to deliver.  By claiming they would design their own vehicles and send people one way they were a laughing stock, but groups that organize passengers and design the necessary surface habitat with the intent to actually run a colony are exactly what Musk needs in a customer.

I also liked his idea of corporate sponsorships for individuals wanting to relocate to Mars. Many younger people might not have the cash to buy a ticket, but I can see companies getting on board to sponsor candidates in the way that sportsmen, adventurers etc. are sponsored today. Especially if the whole TV broadcast aspect comes into play.

$200k is a pittance for a sponsorship from a corporate perspective.

Should probably read the whole thread before posting, but I'm at work with not much time, so sorry if my points have been hashed over already.

M.E.T. is onto something. Sponsorship will quickly swamp personal buy-in, as large wealthy groups buy up seats en masse. For example, universities (or consortia) will pay to send teams of scientists, engineers, whatever. Large corporations will send contingents to establish a presence right away. Hollywood. Even wealthy religious and/or ideologically oriented groups might spend lavishly to ensure their views are well-represented early. In fact I can see this becoming a very controversial issue.

Was also thinking about launch logistics. The return-to-launch-cradle plan seems very risky and likely to cause bottlenecks even in the absence of major accidents. What about mobile (self powered or towed) "landing cradles" for returning stages? After the stage is secured, the, um, MLC moves it to the launch pad, most likely with a trip through a maintenance building on the way. The same crane that lifts the tankers can lift the booster from the MLC to the launch cradle. And, since the tankers aren't expected (at least initially) to land anywhere other than near the launch site, why not dispense with their landing gear (guess I'm only assuming they carry it) and have them land on the MLC's the same way? They have the same base diameter as the boosters.

On the announcement... I was struck by the silence during Elon's talk. Many of his bon-mots didn't fly. Probably some were sitting there thinking "this guy has finally lost it" but most were probably scrambling around under the seats looking for their lower jaws.

I myself was stunned. Still taking it in.

[RoboGoofers]

Because the presentation was about creating a Mars Colony transportation infrastructure.  That infrastructure is intended for the development of a permanent habitation on Mars.  In order to develop that habitation, you're going to need cargo that far exceeds the size and weight that can be shifted through a cargo hatch on the 100 person spacecraft and dropped 30+ feet to the ground.

The specific example referenced in my original question was 'heavy construction equipment'.  Something that will be mandatory for site prep and development of the permanent colony.

https://en.wikipedia.org/wiki/Caterpillar_D11

A lot could be done with just a robotic skid steer and 2 years.

[Space Ghost 1962]

Rvac was listed in the presentation slides as having a 3.85m nozzle, which is less than 14 feet but bigger than the Falcon interstage.

However, there's no reason they can't trim that down to ~3m like the Mvac and still get about 375 seconds of ISP. The SL nozzle is 1.75m and gets something like 365 seconds. Huge improvement over Mvac on FH.

Too much of a distraction. Too many projects.

Musk clearly wants the ICT next. And can fly/prove it suborbitally. That's the one to focus on. While settling F9.

Fair enough. But why stop at suborbital? The crewed ship could (barely) make to orbit without a booster, and the tanker could put quite a bit of fuel in it, again without a booster. With a few fueling missions the ship could do a lunar free return test mission at near-Mars entry velocities.

Focus, focus, focus.

I wanted the Shuttle to fly and do real missions in the 70's. I wanted to see the RSRB's upgraded and missions flown from Vandenberg as well as CCAFS. Didn't happen - too much done by too little takes too long.

A leader has to have a steel spine in choosing a path. Especially in this case.

Yes many things can be done. Before though ask the question ... what will happen? Perhaps you could work things ... backward? In your enthusiasm?

Keep in mind that there are many who won't "be onboarded" even if Musk is selling tickets, regularly flying and watching a city become operational. Human condition. So you can't expect that working things are a "forcing function".

True "forcing functions", like the internet, only happen when people see the conclusion. Makes no difference suborbital, orbital, or lunar. Wish that Bezos would get that too, but he doesn't. Musk does.

So not an aerospace question but a leadership question.