like if there was no competition. Olympics with no competition wouldn't make any sense. So, I think some positive competitive thing would be better and we should definitely not insist that all countries go at the same pace or some collection of countries go at the same pace, that would slow things down dramatically and maybe not even happen. [Encourage ESA.] Yeah, ESA, Chinese space agency, everyone, yeah.
[Audience question about natural resources on Mars.] Well, I think any natural resource extraction on Mars would be - the output would be for Mars. It definitely wouldn't make sense to transport Mars stuff 200 million miles back to Earth. Honestly, if you had like crack-cocaine on Mars, in like prepackaged pallets, it still wouldn't make sense to transport it back here. It's be good times for the Martians, but not back here. Resources would be for a colony to use.
[Audience question about beamed energy propulsion.] The beamed energy thing is interesting. I think it is a worthy area of research. I think it's worth trying to make something work. Try to get something to orbit or a really high delta-velocity with beamed energy and see how well does it work in practice. I do think there's - I mean, I'll state some concerns but these concerns are not meant to say that we shouldn't work on them. I'll preface it by saying we should work on it. I think there are some scaling challenges with beamed energy. If you say, what's the actual power output you need to send, say, a Falcon 9 class vehicle to orbit, and it's a very very big number. You start needing like, woah, we need like the power of like the eastern seaboard, ya know, to sort of send something Falcon - call it Falcon Heavy class, what do you need to send something like that to orbit, it's really a huge amount of energy, or a huge amount of power, to be precise. Actually, the power level you need is enormous. You don't need, maybe not that much on an energy basis, but you can't just tell everyone to turn their lights off in Florida. So then you need like a huge power plant or a huge capacitor bank or a huge high power density battery array. So, I'd like to see how well does it scale, and then you say, what's the cost of the huge power plant and the huge laser array, and that sort of thing and how does that compare to the cost per unit mass if you just carry your own oxygen with you and have a lower ISP and don't do any of those things.
[Audience question about the Hyperloop.] That's cool. What was the ratio of the pod to tube diameter? Right, but, the pod diameter to tube diameter? [Not a lot.] Ahh, that's the problem. So, you actually want the pod to - you want a sort of ratio of the pod area to the - tube cross-section to pod cross-section of about two. So, like, the pod is only half the cross-sectional area of the tube, because you're still going to want to have some flow of air over the pod. Yeah, you'll probably deal with the Canterus limit by having a compressor on the node but it only partly addresses it and then the rest is airflow around the pod. You definitely don't want to have something that's really a tight fit because you also start hitting tolerance limitations like that. Yeah, and you just need some play in that system. A tricky thing also for if you're going really fast is just even small imperfections in the surface of the tube which I think can be deal with by essentially having - once the tube's done you actually need to run something that's going to smooth it out. You basically need to run a grinder through the tube that's going to polish the surface and make sure that there are not undulations. In the proposal of the Hyperloop we had the air-skis were sprung. Yeah, that's also important. [What about thermal expansion?] You actually have to allow expansion at the terminals. Where-ever the terminals are, you have to have that length of expansion and then in the pylons that are supporting it, you actually need to allow each pylon to stretch in x. So, it's - you can't hard constraint it at the pylons.
Yeah, I could probably do 10 or 15 more minutes.
[Audience question about space mining.] We're not really going to try to get resources on the Moon, because that'd be useful if you're on the Moon but not for bringing it back to Earth. So, if there's a Moon base, I'd expect they'd extract resources, but for themselves. I'm going to try to get through a bunch of questions, so I'll make my answers short.
[Audience question about artificial intelligence.] I think we should be very careful about artificial intelligence. If I were to guess at what our biggest existential threat is, it's probably that. So, we need to be very careful with artificial intelligence. I'm increasingly inclined to think that there should be some regulatory oversight maybe at the national and international level, just to make sure that we don't do something very foolish. "With artificial intelligence we are summoning the demon." You know all those stories where the guy with the pentagram and the holy water is sure that he can control the demon, didn't work out. HAL9000 would be easy, it's way more complex than - I mean, it'd put HAL9000 to shame, yeah, like a puppy dog.
[Audience question about Mars communication satellites.] Sorry, could you repeat the question? I was just sort of thinking about the AI thing for a second more. [Repeats question.] Communications is certainly very important. We're going to need tera-bit level communications between Earth and Mars which necessarily means that you're going to want a tight beam, like a laser communication system or something like that, and relays - sort of satellites that relay it - because sometimes Mars is on the other side of the Sun, so you gotta bounce the photons around the Sun, not through it, and yeah, so I think communications are going to definitely be important. I also see that, on Earth, there's a lot of potential for space-based communications. I think that there's a huge amount of room for growth for having satellite communications systems that provide high bandwidth global coverage, and we'll need the same for Mars.
[Audience question about the space elevator.] Haha, I say bravo. I mean, I thought it would be awesome if there was a space elevator. I wouldn't hold my breath. I mean, I don't think it's realistic but I'd love to be proven wrong. I always think of, like, Charlie and The Chocolate Factory when I hear the space elevator, ya know, because people sort of imagine it's like an elevator, you press up and now you're in space. This is extremely complicated. I don't think it's really realistic to have a space elevator. Put it this way, at the point at which we have a bridge from LA to Tokyo, which I think is a much easier problem, then - ya know, how about across the Atlantic, some sort of 2000 mile long bridge, or 3000 mile long bridge, something like that would be made of carbon nanotubes. I don't think we've got a carbon nanotube footbridge so far, let alone some enormous 60,000 mile long space elevator. Anyway, I think it's - it's not the thing that I think makes sense right now but if somebody can prove me wrong that'd be great.
[Audience question about Mars One.] Well, the illustrations that I've seen basically has them using a bunch of SpaceX rockets and Dragon spacecraft. I'm like, okay, if they want to buy a bunch of Dragons and Falcon 9 rockets, that's cool. We'll certainly sell them. I mean, I don't think they've got anywhere near the funding to buy even one, so I think therefore it's unrealistic, and I think trying to go to Mars in Dragon is less than ideal. It's at least - well, if you go real fast it's maybe a three month journey and normally it would be more like a 6 to 8 month journey. That's a long time to spend in something with the interior volume of an SUV. I'd recommend waiting for the next generation of technology.
[Audience question about space elevator.] Well, ya know, I think it would not work. It would just be an illustration on a page that doesn't have real hardware. That would be the difference. I just don't think space elevators are like a very sensible thing, ya know.
[Audience question about reusable energy on the Supercharger network.] Yeah, absolutely. What we're planning to do over time is go to 100% renewable power generation for our Supercharge stations. We've sort of temporally not added solar power, because in the interests of just having national and international coverage, so you can drive anywhere in the US, Europe or Asia using Superchargers, we haven't constrained that so that every Supercharger has to have solar panels. There are a few that have solar panels, most don't. But in the long term..