Author Topic: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD  (Read 441645 times)

Offline Rocket Science

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It's the wee hours of the morning here but did I miss something about no mention of abort modes?

No you didn't. We can assume the BFS takes care of itself if the BFR fails. If the BFS fails, you're toast.
Thanks, I didn't think so and when I couldn't sleep I checked NSF (you know your a space geek when...) All I recall was the engine out ability, but not having abort modes from pad to orbit also raises my brows thus-sly ???...

With 9 Raptors the spaceship could (in theory) do a pad abort to soft landing as soon as there's a minimum amount of LOX in the tank (probably around 10%). There would be a considerable number of technical hurdles to accomplish this, and it would under some conditions be a very slow abort, but the TWR of the fueled upper stage on the pad can be positive. Once in flight TWR isn't so critical as long the ship can maintain control authority.

If the ITS tanker stage is used as a SSTO, it could carry Dragon 2 which has it's own pad to orbit abort abilities.
The Raptor engines "ramp-up" time is too long to be escape engines... YMMV...
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Offline CorvusCorax

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Considering the new booster is a really massive rocket and it will have to make hundreds if not thousands of launches, that is a significant environmental impact from a greenhouse gas emission point of view.

In the following decades politics and population will become increasingly sensitive to that as climate change effects start affecting the living quality of the western world general population to a higher degree.

As Elon Musk has said in the past, Rockets are unfortunately the only thing that can not be run electrically.

Except they can:

SpaceX already needs to develop large scale In Situ propellant synthesis from water and carbon dioxide for the mars operation. All it needs is CO2 + H2O + Energy.

These elements are as readily available on Earth. Building a large propellant synthesis plant in combination with regenerative energy sources near the launch pad will solve two issues at once:

ITS will fly "green" with a 0 net carbon footprint
The In Situ technology can have a large scale test run on earth to see if there's any issues with long term operation and upscaling. (On Mars it'd be a bit late if some critical catalyst starts to degrade over time ad you have no spares)

There's still gonna be more than enough "first"s on Mars, like having to mine ice from underground. It might be possible to test that technology on a Greenland or Antarctic test site (including realistic operation temperatures during the winter) but that location is not very suitable for a launchpad unless you want to add large ships to the supply chain. (Btw Would be fun to load a natural gas tanker with half methane and half LOX and a good load of extra "no smoking" signs - but maybe that's for the party thread ;) )

Offline mclumber1

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Wowza. The ITS is one impressive rocket. 42 engines in the first stage. How many engines can fail and the rocket still get the Mars ship to a useful orbit? Elon said "multiple". I would expect each engine to be surrounded by shielding to prevent one Raptor RUD from taking out the others (like what happened with N-1?).

As far as the ITS crewed vessel, one question that occurs to me is how much payload would it carry if it were just being launched by itself (SSTO) into a low earth orbit like the one Shuttle used? Elon said it was a small number. Better yet, how much of a payload would it carry on a suborbital flight, say from New York to London? If they test it on suborbital hops and find it can work well I wouldn't be surprised if Elon tries to make money by pioneering transoceanic suborbital cargo & passenger services, after all he'll need lots of income to pull this off.

Speaking of tourism, if ITS really works and they fly people as far as Saturn I could see myself enjoying a tourist flight to see the rings of Saturn close up, if I make it out that far.....

Musk being the environmentalist that he is, would probably not use the ITS as a intercontinental cargo/people mover.  The carbon footprint would be astronomically higher than even the most fuel thirsty airplane.  Yes, your package would get to London in a matter of minutes,  but you're burning millions of pounds of methane doing so.

Offline envy887

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What happens if your exploding stage 1 takes out your engines and gear on the pad or low altitude?
The landing gear likely aren't needed for a soft landing - the Falcon 9 stages did soft water landings and floated for awhile.

An explosion violent enough to take out multiple Stage 2 engines probably breaches the Stage 2 tanks, at which point the whole thing goes kabloomy. I don't see a Stage 2 tank breech during an on-pad booster anomaly being survivable, though it might be survivable if it happens in flight and those spheres inside the tanks hold landing prop.

Getting the upper stage moving away quickly as soon as an anomaly is detected would be critical in any evert. And certainly difficult, but not impossible.

Offline envy887

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The Raptor engines "ramp-up" time is too long to be escape engines... YMMV...

Perhaps. But that depends on how long the ramp-up is from the last point in the start-up sequence that can be held for several minutes.

Also depends what type of anomaly you're trying to abort away from, and how fast you can detect it and start the abort.

Offline Cherokee43v6

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any speculation about whether the first rocket to mars will have humans or will he try to setup isru with robotic assembly on mars? It seems it would be hard to setup the isru with robotics. OTOH first humans would have to live there years before the isru can make enough fuel for return.

My thoughts.

The first several flights will probably be lighter on people and heavier on cargo.  The initial mix being geared toward a combination of Construction, Agriculture and Aerospace Mechanical professionals.  The purpose of this mix would be to establish the initial colony infrastructure. 

These flights will also be one-way for the ships.

Why?

Two reasons.  First, the initial colonist will need someplace to actually live while they construct a permanent base.  The ships would have all of the required resources to provide the temporary base camp required.  Second, each of those ships is a store of spare parts to refurbish/repair the follow-on ships that do perform the two-way mission.
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Offline Rocket Science

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What happens if your exploding stage 1 takes out your engines and gear on the pad or low altitude?
The landing gear likely aren't needed for a soft landing - the Falcon 9 stages did soft water landings and floated for awhile.

An explosion violent enough to take out multiple Stage 2 engines probably breaches the Stage 2 tanks, at which point the whole thing goes kabloomy. I don't see a Stage 2 tank breech during an on-pad booster anomaly being survivable, though it might be survivable if it happens in flight and those spheres inside the tanks hold landing prop.

Getting the upper stage moving away quickly as soon as an anomaly is detected would be critical in any evert. And certainly difficult, but not impossible.
So I guess we are in agreement then that there is only "one" failure mode abort "if" the S2 engines and gear are not damaged and that is "abort to orbit". Any CRS-7 or AMOS-6 type event, for sake of discussion are impossible or "iffy" at best... Inline staging is not fool proof and the Shuttle side mount was not the only risky type architecture which is why Orion, Dragon 2 and CST-100 all have a dedicated LES...
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Offline robert_d

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Although the Heart of Gold class or cargo variants that are meant for deep space missions need legs, Tankers or NEO Cargo shuttle variants don't if it's possible to normally land back on the launch stand. Why not apply that mass to something more useful? They could also put launch stands in the bullseye on ASDSs and skip the legs for sea landings too.
Please consider calling them "landing stands" or "landing structures" since that is all they would be used for. This speculation should then move to the regular MCT thread since it has nothing to do with his speech.

Offline dnavas

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So I guess we are in agreement then that there is only "one" failure mode abort "if" the S2 engines and gear are not damaged and that is "abort to orbit". Any CRS-7 or AMOS-6 type event, for sake of discussion are impossible or "iffy" at best... Inline staging is not fool proof and the Shuttle side mount was not the only risky type architecture which is why Orion, Dragon 2 and CST-100 all have a dedicated LES...

How many flights do you need to be confident enough not to have an abort strategy?
How do you get that flight count on a brand new engine and launch system?

Offline muomega0

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A key slide from the  Sep 27 IAC Musk ITS Rollout Talk:
1) Not refilling in orbit would require a 3 stage vehicle at 5-10x the size and cost
2) Spreading the required lift capacity reduces development costs and compresses schedule
3) Combined with reusability, refilling make performance shortfalls an incremental rather than exponential cost  increase

1) this was the theme of the spiral architecture cast aside by ESAS, Boeing's Amplification factor
2) LV independent architecture-- include the rest of the US fleet, IPs, as well as EP, multiple fuels ?
3) The airline analogy worked well here  ~90M for an airplane,   sometimes $50 from LA to 'Vegas

So how does this LV configuration reduce launch costs to open new markets? -- 1000s of Communication Satellites on MCT rather than Falcons?   25 min trip to Tokyo?   Would Falcon/MCT consume all the flight rate?

A steady demand of launch services from NASA (rather than its own HLV), DOD should reduce costs or other markets.  If you remove HSF missions, it implies that DOD costs increase for the same mission set.  Common configurations for Class A payload and higher flight rate provides demonstrated reliability--how does MCT fit in this regard?

The direction is to Mars, a new reuseable, launch vehicle independent architecture, with probable participation of the private sector,   IMHO.

Offline jak Kennedy

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This picture still blows me away, hours later.... I made some rough estimates of the tank diameter, using the people. (who also are of unknown height but the taller ones are likely ~6ft). Taking into account the perspective distortion of a wide angle lens, this tank is at least 10m wide:o So since the geometry matches the spacecraft schematic, this could actually be a full size 12m diameter LOX tank for the spacecraft!

Hmm that LOX tank is also roughly the size of the crew compartment. It seems a little tight for 100 people for 50-80 days!

Also in the diagram of the spaceship I don't see where the solar panels are stowed. Still early days I guess.
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Offline Ben the Space Brit

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Also in the diagram of the spaceship I don't see where the solar panels are stowed. Still early days I guess.

Outboard of the flank Raptor-VACs, I think.
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Online yg1968

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I haven't read all the comments in this thread. But I sort of wonder what is the best way to describe the spacecraft, it seems like a cross between a capsule and a lifting body. It has a black heatshield on one side.

Offline DigitalMan

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So I guess we are in agreement then that there is only "one" failure mode abort "if" the S2 engines and gear are not damaged and that is "abort to orbit". Any CRS-7 or AMOS-6 type event, for sake of discussion are impossible or "iffy" at best... Inline staging is not fool proof and the Shuttle side mount was not the only risky type architecture which is why Orion, Dragon 2 and CST-100 all have a dedicated LES...

How many flights do you need to be confident enough not to have an abort strategy?
How do you get that flight count on a brand new engine and launch system?


What happens if your exploding stage 1 takes out your engines and gear on the pad or low altitude?
The landing gear likely aren't needed for a soft landing - the Falcon 9 stages did soft water landings and floated for awhile.

An explosion violent enough to take out multiple Stage 2 engines probably breaches the Stage 2 tanks, at which point the whole thing goes kabloomy. I don't see a Stage 2 tank breech during an on-pad booster anomaly being survivable, though it might be survivable if it happens in flight and those spheres inside the tanks hold landing prop.

Getting the upper stage moving away quickly as soon as an anomaly is detected would be critical in any evert. And certainly difficult, but not impossible.
So I guess we are in agreement then that there is only "one" failure mode abort "if" the S2 engines and gear are not damaged and that is "abort to orbit". Any CRS-7 or AMOS-6 type event, for sake of discussion are impossible or "iffy" at best... Inline staging is not fool proof and the Shuttle side mount was not the only risky type architecture which is why Orion, Dragon 2 and CST-100 all have a dedicated LES...

Here is what Musk said about abort:


Jeff Foust
‏@jeff_foust
Musk: spaceship can serve as own abort system from booster, but on Mars, either you’re taking off or you’re not. #IAC2016

Offline Rocket Science

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I haven't read all the comments in this thread. But I sort of wonder what is the best way to describe the spacecraft, it seems like a cross between a capsule and a lifting body. It has a black heatshield on one side.
My first take was lifting body...
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Offline rsdavis9

I haven't read all the comments in this thread. But I sort of wonder what is the best way to describe the spacecraft, it seems like a cross between a capsule and a lifting body. It has a black heatshield on one side.

Also not shown is the reentry into earth and landing. I would assume it will be the same as mars but different heat and velocities. I like the 30-45 deg reentry angle.
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Offline Ekramer

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Anyone have any insight to why Jean-Yves Le Gall, the president of CNES (the French space agency) introduced Elon?  I ask because France is the only country I can think of with a popular space program and a popular civilian nuclear power program.  The French people have long supported nuclear energy, and the (mostly) French state owned company EDF is the largest nuclear power supplier in the world.  If there is one country who are willing and able to launch a reactor or nuclear fuel into space, it is the French.

Offline Cherokee43v6

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A steady demand of launch services from NASA (rather than its own HLV), DOD should reduce costs or other markets.  If you remove HSF missions, it implies that DOD costs increase for the same mission set.  Common configurations for Class A payload and higher flight rate provides demonstrated reliability--how does MCT fit in this regard?



One interesting thing that was not mentioned in the presentation that could be a game-changer for launch rates.

Elon mentioned missions to elsewhere in the solar system.  He also mentioned that the cost per passenger was based on 2 tons of cargo per passenger.  If that 2 tons does not include the passenger's required consumables for the voyage the question becomes.

Using the Interplanetary Spaceship how much would a 2 week Lunar Cruise cost per person?  Could that price be competitive with the cruise industry?  I might not be able to afford $200-$500k to emigrate to Mars, but a $10-$20k 'trip of a lifetime' would certainly be of interest.  Remember, the original 'Cruise Ships' were converted from trans-oceanic liners.

The Mars ships have a 1-1.5 year mission every two years.  However, other, closer trips (such as above) could provide a significant flight rate for the booster.

Another thing I'm curious to see is what kind of mass the Spaceship could have to orbit as an SSTO.  The question being, could it operate as a pure 'people mover' from ground to LEO?  What number of passengers could it carry up/down?

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Offline Ben the Space Brit

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I haven't read all the comments in this thread. But I sort of wonder what is the best way to describe the spacecraft, it seems like a cross between a capsule and a lifting body. It has a black heatshield on one side.

It's a 1940s-style pulp sci-fi rocketship. Just compare it to anything from the classic Buck Rogers or Flash Gordon serials!



No bucks...

Seriously, up-thread, someone suggested that it is basically a biconic lifting body but I'll leave that one to the experts.
« Last Edit: 09/28/2016 02:24 pm by Ben the Space Brit »
"Oops! I left the silly thing in reverse!" - Duck Dodgers

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Offline rockets4life97

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That is an entirely different beast than the base financial investment required to get the first people to Mars, which presumably would be quite a bit less than the $10b total. 

The actual amount Elon seems to expect SpaceX to spend over the next 8-10yrs  is something on the order of ~$1.2-$2.4b, based on his assertion that he would ramp up spending to ~$200-$300m/yr starting in a couple of years. 

That isn't going to happen if his current cash flow is interrupted yearly.  Musk said they'd do what they can, which in my mind implies that he was planning on saying more before events intervened.  Even assuming SX was running 10% margins and spending half of that on Raptor dev, another 9+ month shutdown is going to erase a lot more than 10%.  There are some lean years ahead imho.  FH test is put off until a redundant pad exists because you can't risk your only pad.  Some of those customers walk.  Musk said that schedule was for if everything went right.  It already hasn't.  I suspect a full assess is waiting on finding what went wrong.  I don't expect there'll be 9 figures of free cash flow in a couple of years, sadly.

This was my take as well. My main takeaway from the presentation was the Musk was fairly humble about the whole thing. He seemed pretty aware of the challenges in brining to the design to production, but also in the funding. I think that has a direct corollary to the recent failure that has been so difficult to determine the cause. So a lot has to go right. I for one am glad someone is working on a Mars architecture and building real hardware. That is what I find impressive.

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