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Thanks for the comprehensive reply :D If at least the hyperloop project manages to get off the ground (pun sort of intended) that would still be a nice contrib

• Robotbeat 7y ago
  Transport aboard rockets could be about the same price as a business class airline ticket over extremely long distances. But you're right about the safety issue. Rockets are just slightly better than Russian Roulette right now (about 98-99% reliable for the good ones). Part of the issue is the low margins, but also the munitions background of many rockets... and the EXTREMELY high costs of expendable rockets, which means flight rates must be low and you can't get the hardware back for inspection. But SpaceX intends to pursue fully and rapidly reusable rockets, which at least theoretically have the possibility of solving that problem by lowering launch prices by orders of magnitude, allowing greater improvement in reliability by returning the vehicles, and increasing the flight rates enough that you can prove out safety. I'm thinking probably a history of thousands or even tens of thousands of launches are necessary before the first point-to-point crewed launches (for specialized purposes, emergencies, charters) are feasible with reasonable safety, and maybe 100,000 or even a million launches before mass transit usage. Here's an article where a SpaceX representative addresses your exact point, i.e. safety of in-land launches of Starship and how many launches may be necessary to get to that point: https://www.businessinsider.com/spacex-one-million-starship-rocket-launches-commercial-international-launches-2020-1 https://www.businessinsider.com/spacex-one-million-starship-... As far as door-to-door time, IMO, you would need to use like a seaplane or maybe an electric VTOL vehicle (or, heh, a Hyperloop) to get to the launch pad quick enough for the trip to be worth it. As far as energy usage, such long-haul rocket flights may be roughly comparable to Concorde flights by my calculation (if they fill the vehicle up with high capacity seating... which may be a challenge if the tickets are business class prices), and the fuel is planned to eventually be made with the same carbon-neutral solar-to-gas technology (electrolysis of water, then the Sabatier Reaction) that is required for Starship on Mars (which, of course, has no natural gas deposits or free oxygen).
  • njarboe 7y ago
    I think point-to-point launches with people could be happening much quicker than 100,000 launches. He already has a billionaire paying for a moon flyby. Maybe launch 25? People were signing up to pay $200,000k to go into space on spaceship two. People will pay even more to go on an orbital flight. You can keep up the demand by decreasing the price for quite awhile, I would imagine. Unless the FAA gets in the way and just bans people from flying. Hopefully they won't as it would be purely voluntary and probably way less risky than wing-suit flying.
    • Robotbeat 7y ago
      Sure, but there's a very different barrier between joy rides where they make extremely sure you know the high risk of death (and also your heirs, so they can't sue) and regular, regulated mass transit passenger flights from one spot on the Earth to the other. I don't doubt that crewed launches will happen before 100,000. But keep in mind that Starship 1) is supposed to be super cheap to fly with fast turnaround, so you can afford a bunch of test flights and 2) will be used for launching a bunch of stuff into orbit already. Falcon 9 will have nearly 100 launches before it launches Dragon Crew, and that one has a launch abort system. 3) Starship has no full abort system like Dragon, so you're going to have to rely on flight history. Flying people on charter flights may be feasible earlier, as the risk tolerance for general aviation is MUCH higher. Base jumping has a fatality rate of about 1 in 1000, so to get risk down to 1 in 1000, you're going to need around 500-1000 consecutive successful launches (OR a lot of incredibly expensive mission assurance engineering... honestly might be cheaper just to do hundreds of test launches!). Regular skydiving is MUCH safer at 1 fatality in 10,000 or 1 in 100,000. I expect the lunar flyby will require a good 25 to 100 consecutive successful launches beforehand. Starlink is supposed to have up to 40,000 satellites eventually. Starship can do about 400 at a time, so that's 100 launches right there. (There's some confusion, there... some say the permit is actually for 12,000 satellites. But Starship is still expected to do a bunch of regular commercial launches, say about 15-20 flights per year in addition to Starlink). Driving and general aviation (private planes) are much less safe per mile than general aviation. If a Starship flight is 10,000 miles, to be as safe as driving a car, it only needs to get to 1 fatality in 10,000. To get as safe as a private jet (which the rich and famous seem to have no problems using), it's about 1 fatality in 10,000 to 50,000. If we just have to be as safe as taking a motorcycle for 10,000 miles, that's just 1 in 500, which is pretty doable for Starship.
• AlexandrB 7y ago
  > If at least the hyperloop project manages to get off the ground (pun sort of intended) that would still be a nice contribution to human progress. I don’t agree. We already have maglev, is hyperloop going to be cheaper to build/operate? If not, why would the marginal speed increase prompt governments to invest in this kind of infrastructure vs. traditional rail or maglev? The problem is not that hyperloop won’t work, it’s that it is another gadgetbahn[1] that doesn’t make economic sense in a political climate where infrastructure investment is verboten. [1] http://www.cat-bus.com/2017/12/gadgetbahn/ http://www.cat-bus.com/2017/12/gadgetbahn/
  • Robotbeat 7y ago
    Hyperloop is supposed to be significantly cheaper to build and operate due to reduced diameter, reduced impact on environment from noise (really fast maglev and high speed rail can be an acoustics problem, particularly near tunnel orifices), and increased efficiency particularly at the high end (energy consumption per kilometer at high speeds is proportional to speed squared, and as you approach transonic speeds, it gets worse, so pumping almost all the air out can help dramatically... neglecting air friction, and depending on the exact technology, maglev itself is can actually be MORE efficient per ton-mile at high speeds than low). Hyperloop's infrastructure cost is hopefully being solved by The Boring Company (although if they make more than incremental progress in tunneling efficiency, all sorts of tunnel projects in the US--which has particularly bad tunnel infrastructure costs--should improve). Also, if Hyperloop succeeds, it might help loosen the political restraints. Personally, I think The Boring Company is more likely to be successful than Hyperloop itself. There's a lot of really hairy engineering required for super high speeds. BUT the Hyperloop student competition's 10km track could push the state of the art in rail speed, and that may have interesting consequences.
• njarboe 7y ago
  The SpaceX landing pads at Cape Canaveral are 10 miles from populated areas and 50 miles from the large city of Orlando. So we are already landing them near population centers. With fully reusable rockets, one gets to the point where they are better than airplanes because you can use them more (10 flights per day from Sydney to New York and back instead of the 1/2 round trip per day you currently get with airplanes). They cost similar amounts to build, but can make much more revenue/time. Also for long trips (1/2 way around the world) the fuel used/passenger will also be similar. This is of course future tech, but could be coming in the next few years. Elon Musk say first orbital tests coming this year.