Author Topic: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD  (Read 441479 times)

Offline tyrred

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A bit late to this thread, but... Wow, it's been a long day.

Elon's presentation blew me away.  Painted the picture in brilliant, broad stokes.  This looks and sounds to be achievable, as long as the right people have the will to iron out the kinks and make the way.

Should be obvious to everybody here on NSF that the Vision is the prime directive for this architecture.  Meaning that yes, the details DO matter... But c'mon, if anybody truly thinks that Elon can magically communicate all of our nerdy interests on demand, I've got a bridge to sell you.

There IS such a thing as Too Much Information - especially for such a dense topic as this reveal of the leading near-term interplanetary transportation system.  The eyes of the general public are easily glazed.
 
Elon stated that the presentation was based off of the actual CAD architecture as it exists... as of yesterday.  Of course there will be changes.  There are so many trades that must constantly be considered, evaluated, tested, proven.  I for one am just flabbergasted at the ambition of this project.  That SpaceX has actually bent metal (and composites - DAMN that tank is OFF THE CHAIN!) speaks volumes to their commitment to this cause.

By all means, these discussions about the details have utmost merit.  Yet always be wary, ye good people, of getting in lost in a paralysis of analysis.

Many things to be tweaked, but overall Big Picture looks to be realistic: to provide the preliminary primary transportation method to our little brother, Mars.

I'm looking forward to going there... and not coming back  8)


Offline CapitalistOppressor

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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!

Video referenced -


At 36:50 Elon starts discussing the oxygen tank, and then states that they have "started on that element as well, and I'll show you some pictures of that later" at 37:40

At 59:35 Elon continues discussion about the tank, saying "We also wanted to make progress on the primary structure" and then says at 1:00:35 that he wanted to focus first on the Raptor and then building the first "development tank for the Mars Spaceship"

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

Offline woods170

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Going to have huge environmental and health problems if one blows ups or burns on the pad
And would have the largest fatalities in spaceflight history.
Who cares? Hundreds of people die each year in plane crashes and millions in automobile accidents. That doesn't stop aviation, let alone stop people from driving cars. Even the few fatalities in HSF so far have not stopped HSF.

Are accidents and fatalities going to happen? Absolutely! Will this stop people from going places? H*ll no! It never has, and it never will.

Offline tyrred

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

Hopefully the got the recipe right the first time  ;D

Offline hkultala

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Robert Zubrin post on Elon's talk: https://www.facebook.com/robert.zubrin.1/posts/1799839760231952

Overall favourable with this caveat:
Quote
[...]
The key thing I would change is his plan to send the whole trans Mars propulsion system all the way to Mars and back. Doing that means it can only be used once every four years. Instead he should stage off of it just short of Earth escape. Then it would loop around back to aerobrake into Earth orbit in a week, while the payload habitat craft with just a very small propulsion system for landing would fly on to Mars.
[...]

Zubrins model would not be fully reusable, and would not allow return trip.

Elon wants to have a fully reusable system, and to keep the option open for the return trip.

I think Elon's plan is better.

Offline tyrred

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Going to have huge environmental and health problems if one blows ups or burns on the pad
And would have the largest fatalities in spaceflight history.
Who cares? Hundreds of people die each year in plane crashes and millions in automobile accidents. That doesn't stop aviation, let alone stop people from driving cars. Even the few fatalities in HSF so far have not stopped HSF.

Are accidents and fatalities going to happen? Absolutely! Will this stop people from going places? H*ll no! It never has, and it never will.

Every single person who knows anybody who dies in this case will care, that's who.  Making a new transportation system needs to involve the lessons learned from all previous systems, not ignore them.

Offline woods170

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Astonished.

You get to ask ONE question to EM, the day of his LIFE speech on Mars.

and what's your pick? toilets?

#speechless.
As a trained biologist I'm not surprised at all. Over two decades ago my teacher on human evolution warned of this kind of "easy life"-facilitated degeneration of human-kind.

Offline Nibb31

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Who cares? Hundreds of people die each year in plane crashes and millions in automobile accidents. That doesn't stop aviation, let alone stop people from driving cars. Even the few fatalities in HSF so far have not stopped HSF.

Are accidents and fatalities going to happen? Absolutely! Will this stop people from going places? H*ll no! It never has, and it never will.

The difference is that a hundred fatalities in an industry that successfully transports millions of people every year is an acceptable risk.

If you carry 100 people every two years and you lose 100% of them, that's bad business.

Offline Bob Shaw

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Robert Zubrin post on Elon's talk: https://www.facebook.com/robert.zubrin.1/posts/1799839760231952

Overall favourable with this caveat:
Quote
[...]
The key thing I would change is his plan to send the whole trans Mars propulsion system all the way to Mars and back. Doing that means it can only be used once every four years. Instead he should stage off of it just short of Earth escape. Then it would loop around back to aerobrake into Earth orbit in a week, while the payload habitat craft with just a very small propulsion system for landing would fly on to Mars.
[...]

Zubrin makes a good point.

Offline Dante80

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Robert Zubrin post on Elon's talk: https://www.facebook.com/robert.zubrin.1/posts/1799839760231952

Overall favourable with this caveat:
Quote
[...]
The key thing I would change is his plan to send the whole trans Mars propulsion system all the way to Mars and back. Doing that means it can only be used once every four years. Instead he should stage off of it just short of Earth escape. Then it would loop around back to aerobrake into Earth orbit in a week, while the payload habitat craft with just a very small propulsion system for landing would fly on to Mars.
[...]

Zubrin makes a good point.

The idea for this is to launch, land on Mars, unload,  refuel, load cargo/passengers and then come back on the next window. If I understand correctly, Zubrin is talking about an exploration level system, that sheds weight for the interplanetary journey while adding complexity.

You will still need two type of engines for the spaceship (which has to fully come back on its own btw), and you will only save the extra structure needed to get you close to Earth Escape velocity.
« Last Edit: 09/28/2016 10:10 am by Dante80 »

Offline Bob Shaw

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Hm... whole fleet but only one or two pads. That means months of loiter time...

Keep in mind the high cadence implied. If daily and a hundred in fleet, two pads could handle it in a few months.

If the top off tanker load also brings crew, your loiter is 50 days, assuming all depart at start of MOI window.
Now add a few days of bad weather per year and a few other delays and you've got months of loiter time, don't you?

That's pretty much what I said.

What if I've severely underestimated his launch rate. What if its many times a day, like aircraft at a airport? Considerably different result - your 50+ days could drop to less than a week.

The synod of 780 days means that 6000 launches to prepare a 1000 ship fleet would come out to 7.6 per day, if the turn around time is truly airplane like, and the launch site is supplied by an LNG tanker ship every day it's not inconceivable to get that kind of launch cadence out of the two sites proposed.  No one would chose to live withing 100 miles of thouse sites at that kind of noise mind you.  More likely a once a day launch cadence seems more realistic so 8 launch pads perhaps spread over 3-4 sites.

The problem is getting all the passengers into LEO just prior to the mars launch window opening, if all the tankers have been launched and filled and 1000 full tankers are in orbit waiting to offload to 1000 manned ships then just the final 1000 launches need to be manned.  But that would still  takes 1/6th of the synod that's 130 days which is far too long.

A possible solution is to launch the actual mars bound ships empty of passengers, fill them with propellant first and then use a high capacity manned vehicle with people crammed in like coach class airliners and immediately rendezvous with a series of ships unloading a portion of the passengers at each one then landing back on Earth to do it again.  If a 4 to 1 ratio can be established then it only takes about 30 days to transport everyone into LEO.

And in reality the launch window to mars at conjunction lasts about a month, so each ship can depart as soon as it's loaded and their would be no loitering of passengers in LEO other then the time it takes for each high capacity ship to transfer it's passengers.  If that takes 3 days then each high capacity ship can be used 10 times during the window, which would work out to just 25 such ships being needed, a tiny number compared to the huge fleet being imagined, and as these ships stay at Earth they can probably be used for LEO or LUNAR shuttling flights the rest of the time as their interiors are more suited to trips of that duration anyways.

The 1000 ships idea could be decades down the line. Make it 100 ships and that would perhaps be more realistic in the medium term, in my view.

Von Braun's initial Mars fleet had a mix of vehicles: Landers, Crew Transport and Cargo. I can't remember the numbers off hand, but about a dozen vehicles. That'll be the general size of early pioneer expeditions, not hundreds. And the first few flights will be smaller numbers still. Once you get into the longer term you will be looking at a different architecture, as Musk intimated. Mars landers based on the HoG, and Earth to LEO HoG Shuttles will play a part moving the 'self-loading cargo' ((c) Uncle Roger) at either end, with something else doing the heavy hauling. The design as shown yesterday is a great leap forward as compared to anything else that's been proposed, but is going to be improved before the big passenger numbers start. In the meantime, though, this is a great start.

Offline M.E.T.

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Robert Zubrin post on Elon's talk: https://www.facebook.com/robert.zubrin.1/posts/1799839760231952

Overall favourable with this caveat:
Quote
[...]
The key thing I would change is his plan to send the whole trans Mars propulsion system all the way to Mars and back. Doing that means it can only be used once every four years. Instead he should stage off of it just short of Earth escape. Then it would loop around back to aerobrake into Earth orbit in a week, while the payload habitat craft with just a very small propulsion system for landing would fly on to Mars.
[...]

Zubrin makes a good point.

Musk intends to get 12 flights per MCT. Zubrin's proposal would only get one. Also, Zubrin's proposal would presumably not cater for any return flights, as a rocket powerful enough to launch from Mars's surface would not be present. Instead, you would have a kind of enlarged Dragon 2, without the power to reach Mars orbit again.

So he is talking a one way trip then. Which is a completely different concept to what Musk intends.


Offline MP99

I raised a question last week on a related thread about the cost advantages of launching tankers from Mars - to Earth orbit - instead of launching them from Earth itself. Considering Mars's shallower gravity well, would it not require less energy to get fuel from Mars to Earth orbit than from Earth's surface to Earth orbit?

Elon wants to build a few tankers, then get hundreds of uses out of each one, not have to build thousands of tankers and wait 26 months for each one to deliver a payload to LEO.

cheers, Martin

Offline Lar

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I admit that I'm a little stressed about only 3 legs. I worry about tipping over. The squatness helps but still.

Do 4 legs make it more stable? As shown on one the the F9 landings if one of the 4 legs collapses the rocket tips over. With less legs the odds are lower  ::)

It's about tipping forces, not redundancy.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline xanmarus

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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.

Offline vapour_nudge

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Going to have huge environmental and health problems if one blows ups or burns on the pad
And would have the largest fatalities in spaceflight history.
Who cares? Hundreds of people die each year in plane crashes and millions in automobile accidents. That doesn't stop aviation, let alone stop people from driving cars. Even the few fatalities in HSF so far have not stopped HSF.

Are accidents and fatalities going to happen? Absolutely! Will this stop people from going places? H*ll no! It never has, and it never will.
You feel the same way about Virgin Galactic perhaps? Are you a taxi driver or bus driver?  I hope not. How come so many people are buying this stuff from Musk. I'm still not convinced he can get even one person to Mars and back - without even landing on Mars.
I don't buy it. And by 2024? Cone on, how overdue is FH and we are still seeing F9s destroying paying customer's payloads. Etched in my memory is ULA's rocket days before the big thud being taken out for a WDR without a NASA probe on top. My personal opinion is SpaceX are too gung ho and they believe too much in themselves. Very pessimistic but I have seen nothing in SpaceX's recent history that would make me even consider placing my life in their hands, even if they sold a return ticket to Mars for $2000. Are you all looking for something to believe in? Look elsewhere or you are destined to be very dissappointed.
This is all so far fetched, I've known people who did a winter stint in the Antarctic and they'd never do it again. I just returned from a holiday in Africa and the air is far more breathable there and the water runs in rivers
Rant complete. Bah humbug to you all and best wishes to Elon and crew to prove me wrong
I reckon someone owes me a drink
« Last Edit: 09/28/2016 10:54 am by vapour_nudge »

Offline redliox

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I think Zubrin should be happy Elon's taken his ideas and scaled them up into something grand yet achievable.  Zubrin was still thinking "NASA" terms and not "business" ones when he originally conceived Mars Direct, hence why it isn't inherently reusable like Elon made his architecture.

I'm curious what sort of orbit ITS would park into, although I assume LEO.  Many argue for LEO, many against (I'm more to the later myself).  However, if you have to use an orbit LEO would be the wisest since you get the most support from Earth; not to mention if the rest of the trip to Mars and back requires no further orbital rendezvous I'd willingly settle on that.

I still long to find out what the Red Dragons can do.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Semmel

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My personal opinion is SpaceX are too gung ho and they believe too much in themselves.

Kind of the same way the Apollo crew was. We need this type of persons, otherwise progress would be much slower. You might be right to question their abilities to deliver upon their dreams. Maybe they do (fingers crossed) maybe they dont (booooo). But you dont get a Moon landing or Mars base at all if you dont believe in your self. My greatest worry at moment is that SpaceX goes bust before they get to Mars. At this point, the company is like "We get to Mars or we die trying.". Only positive things can come of that.

Offline Oli

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So if we look at non-Mars related industrial purposes for a moment, how does the BFS's cargo bay compare to that of the Space Shuttle, for example? How many times bigger is it?

If you had this system, how much cheaper would it have been to build the International Space Station? Would a handful of launches have been sufficient to put the entire station into orbit?

I estimate 670 cubic meters of un-pressurized cargo bay, that's compares to about 300 for the shuttle, and given that it looks to be divided into 2 decks of 3 meter height each and has small doors for access their is no useful LEO construction can be done with this the way the ISS was built, and I'm having trouble seeing how you get useful habitats that can be used on mars surface either.  The vehicle has the mass margin to lift the ISS in almost one go, but not the volume.

From NASA's lander designs, e.g. the 27mt lander from the EMC, I estimate roughly 200 cubic meters are needed for 27mt cargo (rover, logistic modules, habitats, misc., see here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160004384.pdf). So scaled up linearly, 300mt to the surface (I assume 450mt includes the ITS?) would require 2222 cubic meters. A cargo-only ITS would come close to that volume.

I'm skeptical about the mass ratios of both the ITS and the Tanker vehicle. They're crazy. The ITS can land a lot more payload for the dry mass than any HIAD design I've seen. For the tanker the 90mt dry mass is like 4.2% of the stage mass. For fully reusable vehicles!

On the other hand even if they end up twice as heavy there's still plenty of payload left.

Oh, by the way, I have no idea how they're going to return the ITS within one synod. In terms of delta-v it would occasionally work, but the Earth entry velocities are off the chart.
« Last Edit: 09/28/2016 11:12 am by Oli »

Offline CapitalistOppressor

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I understand the desire to see an entire plan laid out, but since we know that the cost of GETTING to Mars is a significant barrier to GOING to Mars, isn't it significant that Musk is proposing a transportation system that seems to solve that? 

I would agree that the portion of the iceberg above the surface is significant. I find the narrow focus on that portion disappointing, that's all.

Quote

Demanding Musk solve all the problems before presenting the solution to the first barrier is asking a lot I think...

I make no demands on Musk. He can do as he pleases. I just find it amazing that he is embarking on a $10 billion/10 year program on just the bare hope that all the other pieces will fall into place at the right time.

Quote
I think you expected too much.


That much is obvious.

Quote
SpaceX is a transportation provider, and that's what they plan on sticking to.

But a transportation provider should have some idea to whom he is providing transportation. This is the ultimate "build it and they will come" gamble.

Quote
 
This presentation was a call for people to step forward and help.

I saw it more as a $10 billion leap of faith that some people will step forward and help. We'll see who answers the call. It's his money...

I'd just like to point out that the bolded statement appears to be conflating different elements of Elon's presentation and might be leading us astray.  Specifically, I'm assuming that you mean that the 10 years is the approximate timeline for getting boots on the ground that Elon showed on his development timeline at the ~53:00 mark, and that it will cost ~$10b to do this (if I'm wrong, I apologize) -

Source video -



But the $10 billion figure is discussed later at ~1:23:50 and is clearly discussed in the context of the size of an investment needed before the prospective business is capable of generating "some sort of positive cash flow".  Assuming that Elon really means what he is saying, achieving positive cash flow means some semblance of a viable money making business has emerged. 

So, customers are paying to transport cargo and personnel, and that income is covering all fixed and variable costs. I don't think we really know what the actual number is, but I would guess that you would need multiple spaceships making the trip each synod in order to get to a positive cash flow situation.

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. 

When you consider that he estimates the fabrication costs for the three primary elements (booster, ship, tanker) at ~$560m, an investment of that magnitude gets you into the ballpark of what is needed if you assume modest development, tooling and other costs needed to bootstrap the operation.  Any bootstrapping costs over that amount means either the schedule slips to the right, or SpaceX will need to secure additional funding.

Again, we really don't know how much is actually required for the initial mission, but the "positive cash flow" statement would seem to point to a cost well below $10b.  Of course, Elon will still need to find a way to raise the $10b to make a viable business, but that would seem to be over a timeline that stretches well past the initial landings.

« Last Edit: 09/28/2016 11:16 am by CapitalistOppressor »

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