Thanks for having me, it's always great coming back here. This is a really awesome place and I always like talking to people from the aerospace industry. I think, when I came here four years ago, I think that was right before we reached orbit. Maybe just several months before we reached orbit. So just to put things in perspective, while recent years have been good, that has not always been the case. The first three flights of Falcon 1, failed. The first flight failed quite soon, the engine shut off about 30 seconds into flight, it continued ballistically for another 30 seconds and then landed like an anti-tank weapon, not far from the launch site. At some point we'll release the blooper reel, but I think we'll wait a few years before we do that. But from those first days, when myself and the team were picking up bits of rocket off the reef, things have come a long way. We actually had two more failures after that one, and then the fourth flight, in late 2008, was successful, and that was a close one because I'd run out of money, and there weren't a lot of people who were keen on funding a rocket company, and I think if we'd said yes, our fourth launch wasn't successful, but the fifth one's the charm, that would not have gone down well.
Thankfully, the fourth launch did work and that I think gave customers of ours, NASA and others, the confidence to award us additional launch contracts and for additional private investment to come and help fund the company, besides myself. I would like to thank those investors, Draper Fisher Jurvetson, and Founder's Fund, and [indiscernable] for having faith there at an early stage to invest in a rocket company. Since then, we got that fourth demonstration launch to work, and then we did our first satellite launch, which was a commercial mission for Malaysia and that launch successfully put the satellite into orbit and I think it's actually still up there, and then we were able to go from there to develop the Falcon 9. In the Falcon 9, we've leveraged the engine we developed with the Falcon 1, the Merlin 1-C, and we've essentially ganged nine of those together on the first stage, and then one on the upper stage with an expanded nozzle, and that actually gave us about 20 times the payload capability of Falcon 1 because, in the case of Falcon 9, we were using a pump fed upper stage as opposed to a pressure fed upper stage. It's an important difference, for those of you who are familiar with how rockets are designed.
We took most of the lessons learned from Falcon 1 and we were able to apply that to Falcon 9, so that the launches of Falcon 9 were all successful - they all reached orbit. Sometimes there were a little glitch along the way, but they all reached orbit. There's an advantage to having the 9 engines, because if one of them doesn't work and has what we call a RUD - which is rapid unscheduled disassembly - then it still makes it to orbit. That's something we think is important for commercial airliners - all commercial airliners have multiple engines so that if you're going across the Pacific at night and you lose an engine, you don't have to use the life raft or that jacket that they give you which, I think, has not been used effectively, very often. So multi-engine, I think is good, and we're going to keep that philosophy going forward, and where we're going now is to the next generation of Falcon 9, which is a vertical take-off and landing capability. I'll show you the video, which is the first sorta flight of the Grasshopper project.
That craft is actually, quite big - it's about 10 stories tall and that flight was to about five meters. In coming months we'll be increasing the envelope, which is just the sort of thing you do with aircraft, where you have envelope expansion - you gradually increase the altitude and speed and as you see things getting a little wobbly, then you take corrective action - ideally before there's a crater - and you can iterate to a successful outcome. But do I think there will be a few craters along the way. I think that's a likely outcome. We'll be very lucky if there's no craters along the way in creating a vertical landing rocket. Obviously we already know how to do vertical takeoff, but we've got to learn how to do vertical landing. The reason to do the vertical landing is we aspire to achieve a breakthrough which I think is extremely important for rocketry, which is rapid and complete reusability. It's important that it be both rapid and complete, like an aircraft, or like a car, or a horse, or a bicycle. Even if you have to repaint a plane between flights, you'll probably more than double the cost of the ticket. You really need to be able to just reload the propellant and fly again. And that's going to take a bit of effort. It's not going to happen overnight, but we'll keep going in that direction until ultimately it's as close to aircraft-like reusability as one can achieve.
If you compare the cost of the rocket, to the cost of the propellant, you can see why. The cost of the propellant is only about 0.3% of the cost of the rocket, and we have a low cost rocket, it's not like our rocket is expensive. The Falcon 9 is $60 million, and that's for something which has four times the thrust of a 747 and about the same liftoff mass, so that's a good deal, but the propellant is only $200,000. So, if we could use the same Falcon 9 rocket a thousand times, then the capital costs would go from being $60 million per flight to $60,000 per flight. Obviously, that's a humongous difference. Now, there would still be some external costs in terms of service, just like you do on an aircraft, you have inspections and servicing and do all that sort of thing, so there'd be that cost to take into account, but still, it would be dramatically more cost effective to get to orbit, and I think it would open up options that today are hard to appreciate - just as in the early days when - I was just in the camel room, with the Sopwith Camel, I don't think people could have envisioned that you could take a 747 non-stop from Los Angeles to London. So it's similar, when we say today that we can see where things will be in the future, but if we enable that capability then that would improve the technology, then all sorts of things happen. We've gotta make that happen. We've gotta achieve that goal.
I think it's a pivotal step on the way to establishing a self-sustaining civilization on Mars. If we don't do that I just don't think we'll be able to afford it, because it's a difference between something costing a half a percentage each year of GDP and all the GDP.. obviously it can't be all of the GDP, we'd get a lot of complaints about that, but half a percent of GDP, or maybe quarter a percent of GDP, okay that's manageable, and I think most people would agree, even if they don't intend to go themselves, that if we're spending something between a quarter to a half a percent of GDP on establishing a self-sustaining civilization on another planet is probably worth doing. It's sort of a life insurance policy for life, collectively, and that seems like a reasonable insurance premium, and plus it would be a fun adventure to watch even if you don't participate. Just as, when people went to the Moon, only a few people actually went to the Moon, but in a sense, we all went there vicariously. I think most people would say that was a good thing. When people look back and say what were the good things that occurred in the 20th century, that would have to be right near the top of the list. So I think there's value, even if someone doesn't go themselves.
So that's why it's really important. Then, if you get to, well, why don't we have fully and rapidly reusable rockets? Why doesn't someone just do it? Well, it's quite tricky, that's the reason. We live on a planet where this is not easy. It's possible, but quite difficult. If we lived on Mars, this would actually be a quite easy thing. But, at 1g, this is just barely possible, I think. The reason it hasn't occurred in the past, is that when people try to design a rocket, and even one that is expendable, after a lot of smart people have worked on the rocket using advanced materials and various techniques, you typically get 2 to 3% of liftoff mass to orbit, and that's expendable. So if you say, okay, well, what if you want to add in the reusable bits? Adding the reusability tends to take another 2 to 3%. So then you end up with zero or negative, and there's not much point sending a rocket to orbit with nothing on it. In the past, things have been cancelled when it looked like success was not one of the possible outcomes. In fact, usually they've been cancelled after it was clear that success was not one of the possible outcomes. So, the trick then, is to make a rocket that is so mass efficient that it gets close to 4% of its payload to orbit in an expendable configuration, and then improve the weight of the reusability bits, push that down to around 2% and you get a net of four minus two - so, on the order of 2% of your payload to orbit in a fully reusable scenario. That requires paying incredibly close attention to every aspect of the rocket's design. The efficiency of the engine, the weight of the engine, the weight of the tanks, the legs, even the secondary structure, the wiring, the plumbing, and the electronics, making sure your guidance system is extremely precise, and just pulling all sorts of tricks - every trick in the book - and then coming up with some new ones. In order to achieve that level of mass efficiency.
Now, I think I see a path to making this happen, but those could be famous last words. That's what we're seeing the beginnings of. It'll take a while, I don't know how long it'll take, but I'm hopeful that we can start to bring back the first stage in the next year or two. We've already brought back Dragon, so we know what bringing something back from orbit is like, and we'll start to reduce the mass rquired to bring something back from orbit. We really have to hone it down so that the thermal shielding and the strengthening of the structure is only just what is needed to come back and not any more. And then I think, perhaps full reusability is in the 5 to 6 year time frame, but that could be famous last words. So that's our goal.
That's the most important thing, technically, that SpaceX has to achieve, and in parallel we're doing things like the Falcon Heavy, which will have two additional first stages as side boosters and with the upgraded thrust of the Falcon 9 that will take it to nearly 60% to 65% thrust of the Saturn V - just to put it into perspective. Maybe around 4.5 million pound thrust, which is about twice as powerful as any other rocket on Earth but, I think, if you want to go to Mars you need something substantially bigger than that. So, some future vehicle will likely aim to be quite a bit bigger than that.
So that's where SpaceX is and stay tuned for more developments. With that said, I'm happy to answer any questions from the audience. So let's jump in.
I should have remembered to play this video. This gives you a sense of what I'm talking about for the reusability. Now, this was done by a modelling team, it wasn't done by the SpaceX engineering team, so it's not entirely specifically accurate, but it gives you a sense for things at least. So, now we've gone through stage separation, the first stage is going to turn around and reignite - it's actually going to reignite three of the engines, not - see, it's doing three there - it sort of magically got rid of the inter-stage which is obviously, not supposed happen, and the real legs are much bigger than that, those are the little guys. But that's approximately - imagine much bigger legs, and a much taller stage with an inter-stage on top, and that's approximately what will happen. So yeah, that's the vehicle, and then there's the next generation of Dragon, the Dragon version 2, which actually does not look like that, but we'll be unveiling that fairly soon. I think that is pretty cool. Dragon version 1, we didn't really know what we were doing, most likely know more at this point. That's why Dragon version 1 looks fairly similar to things in the past, we thought, well, better not stray too far from things in the past, and hopefully it worked. Yeah, so the next version of Dragon will do that, but it looks a bit different, but it'll have legs that pop out and it has eight thrusters that are arranged in four pairs around the exterior. On the actual vehicle, the pairs are not at quite 90 degrees, partially because we wanted to shift the engines that are on the wind-ward side of the back shell, a little more towards the lee-ward side, so they're not quite 90 degrees apart, they're a little closer together on one side, and they're much bigger than what you see there. The super-Draco engines are designed to accelerate the Dragon spacecraft at over 6 gees. So you can go, basically, depending on what sort of dynamic pressure you're facing, go through the sound barrier in about three seconds. I think at altitude your thrust increases, so you're more like 7 to 8 gees.
So, sorry, you're asking about, what have we done in respect to thinking about Mars, sort of, colonial systems? The question is, how did I come up with half a million dollar price tag to move to Mars. Well, umm, I sorta started back from the half a million dollar point. To say, sorta, umm, well, in order for Mars to become a self-sustaining civilization, the ticket price has to be low enough that if someone were to work hard and save up then most people in advanced countries in, say, their mid-40s or something like that, could put together enough money to make the trip. I thought, a half a million dollars, well, that's a middle class house in California, basically. Sometimes it's hard to get one for half a million dollars. So, something on that order, that's roughly the right order of magnitude, and then, working backwards, well, you definitely need to have full reusability because even partial expendability would kill that price, and then you need to use a source propellant, a source fuel I should say, because liquid oxygen is incredibly cheap, it's like 2 to 3 cents per pound, so really it comes down to the fuel and pressure, and well, the cheapest fuel is methane.
So it's gotta be methane, and the nice thing about methane is you can create it on Mars, because Mars has a CO2 atmosphere and there's a lot of water ice as well - and conceivably, you might be able to extract water from the atmosphere, but that may be harder than simply mining water. With water you've got H2O, plus CO2, that gives you CH4 O2, and bingo, you can replenish propellant. Now, you can do this either with hydrogen, or with methane. For a while, we were sort of going down the hydrogen path, and I was looking at the numbers and you get to roughly equivalent delta-v with methane or hydrogen, because of the better mass fraction of the methane system, and then you combine that with the fact that methane is much easier deal with, it's not a hyper-cryogen, and it doesn't have the wiggly hydrogen molecule that likes to get into all sorts of unpleasant places which causes metal embrittlement, and create invisible high temperature fires and that sort of thing. So methane is just sort of a much easier thing to deal with and so - performance about the same, easier to deal with, obvious move in that respect. And actually, with a properly designed methane engine, a staged combustion engine with decent combustion efficiency in the 99% range and reasonable area ratio, 380 isp is quite achievable. The Russians, in ground tests, have achieved 380 isp. So this is clearly an achievable number. So that's sort of the production we're thinking of going, for that.
So yeah, you want something that is pretty big. You know, because if they're going to have to spend a lot of months in it, it can't be the size of a minivan. A round trip to Mars, with 6 months there, 18 months on the surface and 6 months back, two and a half years, you want a little room. I shudder to think of doing that in Dragon. You'll come back batty, if you come back. I think Dragon could be quite useful as a generalized science delivery platform for anywhere in the solar system, because, with propulsive landing you could - that's a generalized solution. You could land on any solid or liquid surface in the solar system, and I think, really, enable a lot more science missions for a low budget, if getting there is taken care of. So that's why I do think Dragon is going to be useful in that respect, apart from being able to carry cargo and people to Earth orbit missions and maybe some other missions too.
'Big Dumb Booster' usually refers to a pressure-fed stage. It usually means, minus the turbopump. I think that is actually not a good way to go. You want the turbopump, otherwise your rocket is just too heavy, because if you go with a pressure fed stage, your entire stage has to operate something like the chamber pressure, and you'll have a ton of pressure left there at the end of the flight. So it's just not a great way to go. Turbopumps are hard, but they're not that hard. They're just a spinning centripetal pump, that's tricky, but they're not that tricky. The hard thing about a rocket engine is just getting those last incremental seconds of ISP. That's where it's really quite difficult, and those last seconds of ISP matter a lot for something that's going to go beyond Earth orbit, where just every little tiny bit of ISP is important. So I really do think you just have to push everything to the limit in terms of advanced materials, smart design of everything, high efficiency engines, everything, it's all got to be pushed to the limit. What you don't want to do though is have insufficient margin in your engines and structure such that you have to rebuild them after returning them. That's, I think, an error that was made with the Shuttle. The SSMEs were just really difficult to reuse. They required a lot of inspection and parts replacement between flights. So I think we may need to back off a little bit on our chamber pressure, still aim for a high combustion efficiency but back off a little bit on chamber pressure.
Where SpaceX, I think, does quite well is in the mass ratio of the stages. We have a very good stage mass ratio that's, with the current version of Falcon 9, the first stage is around the 94% propellant by mass, and with the new design of Falcon 9 we're closer to 96%, maybe 95.5%, and with a slight improvement in ISP. The Merlin architecture is an open cycle architecture, so it doesn't have the ISP advantage of a staged combustion system, and it's using RP-1 so we're talking ISP for the first stage booster engine around 310 to 312 and, for the vacuum version, that's around 340 to 345. The penalty for an open cycle engine is much less in a vacuum than it is at sea level. So that's where we are. So, we definitely need a new engine for any kind of, sending people to Mars kind of stuff, but I think we can still get to full reusability with the current engines despite having a bit of an ISP disadvantage relative to say, the Russian kerosene based engines.
I should have, to be clear, when going through escape, the super-Draco engines on Dragon will generate a minimum of six gees and depending on the scenario that could go up to eight gees. It kinda depends on how much weight you have loaded on and whether you're at altitude or not. The rocket, actually limits the thrust to five gees on ascent. The rocket will actually throttle or shut down engines in a normal scenario to limit the acceleration to five gees. That's set really by the comfort level of the satellites. Five gees is like a nice amusement park ride.
We don't like to talk about our customer's payloads - that's up to them. We respect the privacy of our customers. Direct your question to Bob Bigelow. One thing I should point out though is I think we've got about 46 or so launches on our manifest and, not all of them are actually on the website - almost all of them are, not all - 12 of those are for NASA but the remainder are commercial. "Sometimes people are under the impression that NASA is the vast majority of our business, but actually they're the biggest single customer but they're only about a quarter of our orders."
I don't think anything that's happen will affect the order of flights that will happen next year. I think we'll probably do four flights, that's my best guess, five if we're lucky. One of those flights will be the last of the Falcon 9 version one and we expect to do at least three flights of the upgraded Falcon 9, and we might do a fifth flight, we'll see. We'll certainly have the rockets produced, I feel very confident with that now the rocket production rate is ramping. So we'll have the rockets on the ground, it's just a question of whether the satellites are ready or if there are any other constraints or unexpected things that we encounter, but we'll have the rockets manufactured.
That's a tough one. Once we have better reusability, I think improvements to reusability are going to be pretty important. That's really a fundamental one. I can't think of anything that's on-par with that, short of maybe warp drive. Well, ya know, just focus on SpaceX and Tesla for a while. In fact, I would like to just slightly decrease the amount of time that I work. I think I'll be able to do that when Tesla is cash flow positive which hopefully is quite soon. I definitely do not want to run a third company. I have some ideas.. the Hyperloop, which I think could be cooler than just having another bullet train. Hopefully I'll be able to publish something for that sometime this year. I want to vet it with the teams at SpaceX and Tesla and a few other people, put it out there, and then ask people to contribute ideas and see if there's a better way to deal with - to make it even better - kinda like a wiki version of it or something, and then there can be some collaborative standard design that people think is a good way to go, and then anyone who wants to build it can just build it. I think that'd be great. I think there's a possibility to have a vertical takeoff and landing electric jet, and I think that's where things will eventually end up, it just may take a while to get there.
I'm hopeful that the first human mission to Mars is actually some collaboration of private industry and government, but I think we need to be prepared for the possibility that it has to be just commercial. That may take longer, because it'll require marshaling more resources - well, you have to get the money together to do it. I want to prepare for a scenario where either path is possible. Basically, it needs to happen one way or another. That's the important thing. I'm not dogmatic as to how it occurs, just that it occurs.
[Question about China.] I think we'll probably be competitive. Collaboration is difficult because, in a large part, I don't think they want to collaborate and sometimes competition is good. My guess is probably not collaboration but hopefully friendly competition.
[Question about physiological challenge of going to Mars.] I think it won't be too bad. We know that people can survive in deep space because the astronauts that went to the Moon lived long lives and were none the worse. We also know that people can live in zero-g for long period of time - I think the record is almost two years or something like that. There were plenty of cases where it was 6 months to a year, which is the journey time to Mars. You'll need to exercise along the way, to make you don't have muscle or bone atrophy but I think it will be okay. In terms of shielding against solar radiation, solar storms, sometimes that problem is stated as you need several meters of water to shield yourself and then somebody does the calculation for the volume of a sphere and that ends up being some enormous quantity of water, but you don't need that, you can just have a column of water pointed at the sun and make sure that you're mostly in front of that column and you should be okay. So I don't think it's a huge show stopper - it's certainly not a show stopper and we'll figure out ways to make it better and better over time. [Is SpaceX doing it?] We're just focused on the things that I was just talking about, but there will be at some point.
[Question about Reaction Engines.] This is using an air breathing engine? When I looked at the numbers it didn't seem too compelling compared to having a slight increase in the size of the first stage. So if you're going to add a whole bunch of complexity, it needs to really pay off and, at least using the numbers I've seen, I have a hard time seeing how it does pay off - but I could be wrong about that. If there is really a big advantage then it would be worth investigating, but it would have to be a big advantage. I would be reluctant to add essentially some sort of jet engine on top of the rocket engine problem.
[Question about horizontal air launches.] That's a tricky one. Well, I think it's important to keep in mind that the payload to orbit advantage from an air launch is negligible. I think this audience understands that, but most people don't, because it seems like, well, you're high up there and so surely that's good and you're going at, say, 0.7 or 0.8 Mach and you've got some speed and altitude, you can use a higher expansion ratio on the nozzle, doesn't all that add up to a meaningful improvement in payload to orbit? The answer is no, it does not, unfortunately. It's quite a small improvement. It's maybe a 5% improvement in payload to orbit, something like that, and then you've got this humungous plane to deal with. Which is just like have a stage. From SpaceX's standpoint, would it make more sense to have a gigantic plane or to increase the size of the first stage by five percent? Uhh, I'll take option two. And then, once you get beyond a certain scale, you just can't make the plane big enough. When you drop the vehicle, the rocket, you have the slight problem that you're not going the right direction. If you look at what Orbital Sciences did with Pegasus, they have a delta wing to do the turn maneuver but then you've got this big wing that's added a bunch of mass and you've able to mostly, but not entirely, convert your horizontal velocity into vertical velocity, or mostly vertical velocity, and the net is really not great. So, Orbital, for example, is an interesting example. They started off with the Pegasus as an air launch vehicle and then ultimately did not do any air launch vehicles.
[Question about making money by going to Mars.] There is definitely some amount of money that has to be spent establishing a base on Mars. Basically, getting the fundamentals in place. Call it the activation costs of a Mars base. That was true also of the English colonies. They really took a significant expense to get things started. You really didn't want to be part of Jamestown, it was not good. It took quite a bit of effort to get the basics established before the subsequent economics made sense. So there is that investment and we'll need to gather the money to do that, but then once there are regular flights, that's right when you need to get the cost down into the half a million dollar range for somebody to move to Mars, because then I think there would be enough people that would buy that - they'd just sell their stuff on Earth and move to Mars - to have it be a reasonable business case. It doesn't need to be many people, there's 7 billion people on Earth, probably reach about 8 billion by the end of the century, and the world on the whole is getting richer, so I think if only even 1 in 10,000 people decide that they want to go that'll be enough, even 1 in 100,000.
[How many people on a flight?] In the beginning you'd go with a smaller number of people and you'd have a higher proportion of cargo and emergency equipment and that kind of thing. Once you really got rolling, you'd increase the number of people on the flight because you'd have supplies there. So you wouldn't need to worry about carrying with you all the supplies for the journey there, the stay on the surface and coming back. So initially you start off with maybe a handful of people, less than 10, just trying to give orders of magnitude here, but then you'd go to 100 or more in steady state, down the road.
[Question about MCT engine.] MCT is not an engine. We're only doing one engine, one major engine, and that's the Raptor engine, which is the methane engine. We're going to talk more about the details of that next year, but we're not doing another engine. [Are you going to work with the Russians?] No. We might hire a few Russians but.. yeah.
[Will you go yourself?] I would like to go to Mars, yeah. I want to make sure that things are going well on Earth. Basically, if I die, I want to make sure that things going the way they should. As long as I felt confident of that, then.. yeah.
[Question about European space.] My answer in respect to Ariane is that, I think, any variant of the Ariane 5 is not going to be competitive with Falcon. So the right move, I think, would be to rethink the architecture of Ariane 6 or - if they want to call it Ariane 6 or something else - but think very carefully about that architecture and make sure it has a chance of beating Falcon otherwise it's kind of a pointless exercise.
[Question about the space elevator.] I'm not so much about the space elevator. It has sort of a childhood feeling. "I always kind of think of Charlie and the Chocolate Factory when someone mentions the space elevator." The problem with the space elevator is that first we'd need a lot of launches just to get the carbon nanotube rope up there in the first place and then this thing would be anywhere from 40,000 to 60,000 miles long - umm, that's long - and nobody's yet built a little ya know, foot stool, out of carbon nanotubes, as far as I'm aware - so having something that's 40,000 miles long is a big leap, and there's other issues. It ends up being this big sweeper going through Earth orbit and any orbital debris is going to be really good at catching and it's going to be very high impact. And once you get to the end of the elevator, you've gotta do something otherwise you'll be flung out into space, so you still need rockets. So really all the space elevator would be is a means of reducing the cost of transporting propellant to orbit. In that way, it might work as a long term optimization, not anything worth working on right now.
[Question about crew on Dragon.] In terms of crew, we expect to be ready to fly our first crew mission in about three years. "Technically, if somebody were to stow aboard the cargo version of Dragon, they'd actually be fine. I mean, hopefully." If it came back, they'd be fine. In the pressurized volume we actually maintain sea level pressure, we maintain humidity, we maintain the temperature very precisely because we're trying to transport experiments that have plants and mice and fish and that kind of thing, to orbit and back. So, you could certainly stow away, and do it, but in order for it to be really safe enough we want to establish a standard of safety beyond the space shuttle and anything else prior. You really want to have a launch escape capability, and you want to have lots of flights under the belt, and tested without anyone on-board before putting people on-board. The long lead for Dragon version two is the testing of the launch escape system, and that's what drives the three year time frame.
[What's your largest inspiration?] Well, I really liked sci-fi when I was a kid, and, I'm not sure, I mean, there's many forms of inspiration, I really like Asimov books and Heinlein books, and Arthur C. Clark, and all the other stuff, Star Trek, Star Wars, Battlestar Galactica. From an inspiration standpoint... having read all those books and seen all the movies, and many other books and movies, just the idea of having a future where that didn't come true, just seemed terrible. So that's my inspiration.
[Why Mars and not the Moon?] "We're happy to take people the Moon. If somebody wants to go to the Moon, we can definitely do it." But as far as making life multi-planetary, you know, tautologically one must have a second planet and the Moon, it's a small rock orbiting the Earth with no atmosphere, 28 day period, very little water, lacking in a lot of the key elements one needs for creating a civilization. It's analogous, I think, to the arctic. The arctic is close to Britain but, it kinda sucks over there, and so, that's why America is not there, and it's where it is. Even though it's a lot harder to cross the Atlantic than it is - I mean, from Norway you can practically row to the arctic, in fact I think they did. So, it's really because it's the place where one can establish a self-sustaining civilization and really grow to something significant - really big - and in a worst case scenario, if something were to happen to Earth, you have redundancy. Whereas, that would be much harder to do on the Moon and plus, if something calamitous has just happened on Earth, it is very close, so it might affect the Moon too.
[Question about space colonies.] The problem with space colonies is not that it can't be done, is just that's doing it the hard way. In order to create a substantial space colony you have to transfer mass from a planet or from some asteroid, or something. You have to move mass from one place to another. So why move mass from one place to another instead of just going to where that mass is in the first place? Any sort of orbiting space colony is always, in order to expand, is always going to have to pull mass from somewhere, and why bother doing that? It just seems like a much harder thing to do than just going... [objection about asteroids] it'd actually be harder to travel to the asteroid belt than it would be to travel to Mars. So, if you're talking about people coming from Earth, it's going to be easier to go to Mars. Having the atmosphere, you can use atmospheric breaking as well, and you just have an enormous number of resources on Mars. Mars is like, it's not perfect, but it's pretty good. It's got a 24.5 hour rotational period. It's got a CO2 atmosphere, which means if you just had a transparent dome and pump, you could actually grow Earth plants in martian soil. In fact, it's recently turned out that martian soil is non-toxic so you could actually grow Earth plants in martian soil just by heating it up and pressurizing it with CO2 - you need a little fertilizer, but Mars actually has 2.7% nitrogen in the atmosphere which means that you can synthesize fertilizer as well. So yeah, it's a pretty good option. In fact, it's the only option, I think.
[Question about the meaning of spaceflight availability.] I'm sure it'll make it more awesome to be a human. I think it'll be really great. I think that would make for a very exciting future. We start off by establishing on Mars and eventually spread out to the rest of the solar system and start sending ships to other star systems. Once we've got a large base on Mars, and a lot of travel between the planets, that's a great forcing function for the improvement of space transport technology. I think we'll see rapid improvement and all sorts of inventions that we just can't envision today.
[Question about Mars transport business plan.] At least in the short to medium term, we'd operate them, but I'm not opposed to selling them and having others operate them. It does require some additional effort to be able to hand off something so that somebody else can use it. I think long term it probably will be an airline type model. Short to medium term it'll probably remain something similar to how it operates today. [What's the market?] Forecasts are always tricky. If you asked somebody at the dawn of air flight, what are your market forecasts? I mean, they're going to be wildly wrong. Probably on the low side. Even probably the most optimistic people at the beginning of aviation would seem like pessimists today.
[Question about nuclear and other exotic engines.] Hey, I think liquid fueled rockets are interesting. Throw me a bone. I think, for interplanetary transport, having high efficiency high thrust ion drives could be helpful. I think that's something you'd want to do anyway, because if you have a big spacecraft with a lot of excess power generation, you might as well strap an ion drive to that. So then there's a question of how efficient can you convert power to thrust, so that's one thing. Then potentially something like an electric-magnetic sail would be cool. Yeah I think that would be kinda neat. On the nuclear side, I think that's tough. It's really tough taking up a lot of nuclear fuel in a rocket. People have a hard time with establishing nuclear power stations, how would you like one that's flying over your head and might crash? I mean, we all might think that's a good idea, but we're in the minority.
[Have you heard of Kerbel Space Program?] No. I didn't know that.
[Question about in-house production.] I think vertical integration is sensible. You just need to look at it and say, okay, if we made it ourselves, how much would it cost and if someone else made it, how much would it cost, and then go with the one that is more efficient. I mean, that's really how we operate. That's resulted in, I don't know, 70 % depending on how you count it, by mass or by quantity, 70 % of the rocket is built from raw material at SpaceX. Actually, we'd like to do less. It's not as though we want to do it all. If we could find more efficient suppliers we would be able to offload some of that stuff.