- sub-cooled methane/oxygen system where the propellants are cooled close to their freezing temperature to increase the density, we could definitely do full reusability - and that system is intended to be a fully reusable Mars transportation system. So, not merely to low Earth orbit but all the way to Mars and back, with full reusability. [Within 3 years?] Ha. I am an optimistic person, but - I think we could expect to see some test flights in the five or six year time frame. But, we're talking about a much bigger vehicle, and we're also going to be upgrading to a new generation - a harder engine cycle, which is a full-flow staged combustion. What we have right now is an open cycle engine. Right now, I'd say, engines are our weakest point at SpaceX, but they will become as strong as the structures and avionics in the next generation.
[Question about established competition.] Sure, but let me just clarify a point. I think, right now our weakest point is engines with respect to specific impulse, but not with respect to thrust-to-weight. We actually have the highest thrust-to-weight of any engine, I think maybe ever, but our specific impulse, the efficiency of the engine is about 10% worse than a staged-combustion engine using the same propellant. In terms of our competitiveness, I think it mostly comes down to our pace of innovation. Our pace of innovation is much much faster than the big aerospace companies or the country-driven systems. This is generally true, if you look at innovation from large companies or smaller companies, smaller companies are generally better at innovating than the larger companies and it has to be that way from a Darwinian standpoint as smaller companies would just die if they didn't try innovating because otherwise people would just keep buying the product from the big company. So, then, why is SpaceX more innovative? I think it's probably because we've got a super-engineering driven culture. We're running sort of the Silicon Valley operating system. It's kind of hard to describe. Like, how do you describe Linux. Ya know, like Linux is more efficient than some other operating systems, but to explain exactly why, you really have to get into the weeds. But, you sort of have a very flat hierarchy, you promote rapid communication, a best-idea-wins culture - as opposed the the having the seniority of the person decide the solution, which - that should never be the case in engineering, it should always be a rational basis. I also believe that at the leadership level, I'd much rather promote someone that has strong engineering ability than so-called management ability. "We do hire some MBAs but it's usually in spite of the MBA, not because of it."
[Question about minimum flight rate for reusability.] Well, it is a chicken and egg situation, the reason why there's low demand for spaceflight is because it's ridiculously expensive, and so at some point someone has to say, okay, we're going to make something that's much more affordable and then see what applications develop. That's what has to happen. The situation in rocketry is like if an aircraft - imagine if aircraft were single use, then how many people would fly? The flight rate would be really low. If you buy a 757 it's like $250M, or maybe $300M, and you need two of them for a round-trip. No-one is paying half-a-billion dollars to fly from Boston to London, and if that were the case there'd be like a very small number of flights for scientific and military purposes and people would say, wow, the market for aircraft is so tiny, people really love going by boat - it's nonsense. If we have rockets that are reusable, we could - fully-reusable and can get to a decent flight rate, the potential is there to get a two order of magnitude reduction in the cost of space transport, which is, I think, vital for establishment of a self-sustaining civilization on another planet or even on the Moon or some sort of L5 colony or whatever, but you really need to get the cost down - we need a two order of magnitude improvement, at least, in the cost of transport. In fact, relative to the estimates of what it costs to do a manned Mars mission, I think like some of the lower estimates are at the $100B to $200B level, for a four person mission, we need more like a 10,000 fold reduction. I mean, so people can afford to go.
[Question about space tourism.] Yeah, private spaceflight is going to be some amount of market. Yeah, I don't really know. We're just trying to advance rocket technology and - I mean, on the one hand, if we get even slightly towards the overarching goal of Mars colonization technology level, if we just get slightly there, we certainly have a viable business in launching satellites and servicing the space station, that kind of thing, because - yeah, like, even for like 5% - there's still a viable business doing Earth orbit and we're vastly more competitive than the other rocket companies. We do have a lot of people ganging up against us these days.
[Question about getting to Mars.] I don't think the Moon is a necessary step, but I think if you've got a rocket and spacecraft capable of going to Mars, you might as well go to the Moon as well - it's along the way. That's like crossing the English Channel, relative to Mars. So, it's like, if you have these ships that could cross the Atlantic, would you cross the English Channel? Probably. It's definitely not necessary, but you'd probably end up having a Moon base just because, like, why not, ya know. It terms of the key technologies, obviously it would be great to have some sort of fundamental new thing that's never existed before and pushes the boundaries of physics, that'd be great, but as far as the physics that we know today, I actually think we've got the basic ingredients - they're there. I mean, if you do a densified liquid methalox rocket with on-orbit refueling, so like you load the spacecraft into orbit and then you send a whole bunch of refueling missions to fill up the tanks and you have the Mars colonial fleet - essentially - that gets built up during the time between Earth-Mars synchronizations, which occur every 26 months, then the fleet all departs at the optimal transfer point. I think we have - we don't need any sort of thing that people don't already know about, I believe. I believe we've got the building blocks, but the mass efficiency is extremely important. So, having better heat shields, that obviously are reusable. [What about radiation.] Yeah, things that can mitigate the radiation effects would be certainly - I think the radiation effects are way overblown because, ya know, people went to the Moon. We went like two weeks in deep space. Buzz Aldrin's still around. So obviously they're still alive and they seem okay. Ya know, people have been up in the space station for like a year or more. They're okay. I think there are things we can do to mitigate the radiation on-route, by effectively placement of the water you bring with you - put that in the direction of the Sun. But yeah, I really think we have the essential ingredients, but we do need an efficient propellant depot on Mars, but I think is really like, there's a lot of hard work and engineering that needs to be done, but it's there. Like, the pieces are there.
[Question about robotic precursor missions.] Yeah, yeah, I think that'd be - like, we have rovers on Mars already, so I think we'll see more robots on Mars and we'll probably want to make sure the propellant depot works - it'd be an automated propellant depot and there is some question as to, what do you do for power generation on Mars? Do you have a nuclear reactor? Then you've got to carry the nuclear fuel there, and reactors are fairly heavy. Do you do some lightweight solar power system? Like, maybe big inflatable solar arrays or something like that. So, just power generation on Mars, I think is an interesting problem, and then just figuring out how to get all the bits of efficiency right for creating, say, methane and oxygen on Mars. Ya know, Mars has got a CO2 atmosphere and there's a lot of water buried in the soil that you can get to.
[Question about one-way trips to Mars.] I think there's plenty of people who will sign up for a one-way trip to Mars. It'd certainly be enough, but I think the question is, is it a one-way mission and then you die, or is it a one-way mission and you get resupplied, that's a big difference. I think it ends up being a moot point because you want to bring the spaceship back. These spaceships are expensive, okay, they're hard to build. You can't just leave them there. So whether or not people want to come back or not, is kind of - like, they can just jump on if they want, but we need the spaceship back. I mean, it'd be kind of weird if there's this huge collection of spaceships on Mars over time. It'd be like, maybe we should send them back - no, of course we should send them back. Particularly if we want to have a colony of some kind that's of significant size.