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SpaceX BFR [video]

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Re: SpaceX BFR [video]

#161

Post by sillysaurus3 »

thesash wrote: post #157
dvdhnt wrote: post #154

Earlier quoted context omitted.

In the video, Musk states that SpaceX believes BFR will match the safety of commercial airliners due to its multi-engine propulsive landing capability.

Yes, totally, I get that they have a plan to make it safer -- my point is that a 20,000x increase in saftey is a massive leap, and that will be the limiting factor for this technology.

Well, your comparison isn't too fair. It seems like you're using the loss rates for modern aircraft capabilities. This is roughly like comparing the crash rates of modern OS's to early Unix.

To put it another way, it seems likely that the safety will increase by that much. Before airplanes, hang gliders were one of the most popular ways to fly, along with balloons. Gliders were incredibly unsafe, because pilots were expected to control the glider by shifting their body weight. This made stalls fatal, since you couldn't recover.

Re: SpaceX BFR [video]

#162

Post by ncallaway »

thesash wrote: post #155
Robotbeat wrote: post #153

Earlier quoted context omitted.

Loss rate for space launches is largely due to the fact that the systems are essentially munitions (i.e. expendable, single-use) and flight rates are very low. Rocket failures for crewed rocket launches are extremely rare, occurring once every couple decades. It's hard to improve on that because low flight rates make data very hard to come by. Airplanes fail much more often in absolute terms, giving you a lot more da…

The loss rate for manned space launches over the past 20 years has been 0.79%. What you're pointing out (only once every few decades) is a factor of the small number of manned launches per year. Actual loss rate is very high. 1/130 chance of loss.

> is a factor of the small number of manned launches per year

That's true, but the person you're replying to spent most of their comment directly addressing that fact.

Re: SpaceX BFR [video]

#163

Post by gr2020 »

planteen wrote: post #116
mtgx wrote: post #80

Earlier quoted context omitted.

I think that depends on whether or not the ticket is something like 50x more expensive. If Musk is proposing this idea then I assume it won't be too expensive, even for rich people. So it should cost significantly less than what private jet trip costs them (because the BFR is not so private after all). Of course, the faster time to destination should also balance things out, but I have a feeling a trip would be more…

Latest claim: "elonmusk Fly to most places on Earth in under 30 mins and anywhere in under 60. Cost per seat should be about the same as full fare economy in an aircraft. Forgot to mention that." https://www.instagram.com/p/BZnVfWxgdLe/ What's a NYC to SHA full fare one way, about $800? I wonder if he is also getting into the fuel business? So if this rocket holds 200 people, that only gives him $160k in revenue. Fue…

I think you're off by about a factor of 5. For example, United Airlines unrestricted full fare (Y class), NYC-SHA one way, is a bit over $3800.

Re: SpaceX BFR [video]

#164

Post by cjsuk »

thesash wrote: post #151

There are three things that would factor into my decision about whether to strap myself to a rocket rather than fly in a plane: time, cost, and safety. Musk & SpaceX are talking a lot about time and cost, but safety is obviously a lot more important. Based on data I found on the internet (so it must be true!) the loss rate for rockets is 20k - 165k higher than the fatal crash rate for airplanes over the past 20 years…

It's less likely and a far better way to go than cancer :)

Re: SpaceX BFR [video]

#165

Post by dzhiurgis »

thinkcontext wrote: post #128
codeulike wrote: post #101

Cost per seat should be about the same as full fare economy in an aircraft. Forgot to mention that. - Elon https://www.instagram.com/p/BZnVfWxgdLe/ Looks like fun. I'd love to see the in-flight safety video! "Make sure there's nothing in your pockets because we'll be hitting 3 Gees. If anything goes wrong, we're all probably toast." I think this was just an interesting idea thrown out at the end of a talk that had mu…

It will have to do intercontinental cargo flights for a while before it can be FAA human certified. They'll probably need to invent whole new classes of safety requirements before it can take passengers.

I doubt they will have any cabin crew and different regulation could potentially mean cheaper operation.

Re: SpaceX BFR [video]

#166

Post by ncallaway »

jokoon wrote: post #149
codeulike wrote: post #99

Earlier quoted context omitted.

Elon Musk: Cost per seat should be about the same as full fare economy in an aircraft. Forgot to mention that. source: https://www.instagram.com/p/BZnVfWxgdLe/

Really? I'm surprised. Well then...

I think the key difference is if you're designing specifically for travel on earth then supersonic jets probably are much cheaper.

However, if you're designing for space and can allocate the R&D costs to space business units, you end up potentially developing something that has better marginal costs to transport people across the earth.

Basically, the R&D of building this is astronomically higher than the supersonic jet. But the (theoretical) promise is the marginal cost isn't that different. However, if you're already doing the R&D for other purposes, then you find yourself owning a system that's (potentially) better for global travel.

Re: SpaceX BFR [video]

#167

Post by mjamesaustin »

planteen wrote: post #116
mtgx wrote: post #80

Earlier quoted context omitted.

I think that depends on whether or not the ticket is something like 50x more expensive. If Musk is proposing this idea then I assume it won't be too expensive, even for rich people. So it should cost significantly less than what private jet trip costs them (because the BFR is not so private after all). Of course, the faster time to destination should also balance things out, but I have a feeling a trip would be more…

Latest claim: "elonmusk Fly to most places on Earth in under 30 mins and anywhere in under 60. Cost per seat should be about the same as full fare economy in an aircraft. Forgot to mention that." https://www.instagram.com/p/BZnVfWxgdLe/ What's a NYC to SHA full fare one way, about $800? I wonder if he is also getting into the fuel business? So if this rocket holds 200 people, that only gives him $160k in revenue. Fue…

In the presentation he mentions that the payload volume is larger than an A380, which seats 525 passengers in a standard configuration or over 800 passengers in an all-economy configuration.

So we're looking at more like $400-$600k revenue per launch. And honestly, if prices came in at 50% more than traditional airlines, you're looking at a hell of a great deal to cut your travel time dramatically.

Re: SpaceX BFR [video]

#168

Post by justin66 »

thesash wrote: post #151

There are three things that would factor into my decision about whether to strap myself to a rocket rather than fly in a plane: time, cost, and safety. Musk & SpaceX are talking a lot about time and cost, but safety is obviously a lot more important. Based on data I found on the internet (so it must be true!) the loss rate for rockets is 20k - 165k higher than the fatal crash rate for airplanes over the past 20 years…

> the loss rate for rockets

I wonder how you constructed that comparison such that it seemed meaningful. I'm pretty sure the lesson when you look at the data would be "fly on a man-rated Soyuz, not a Space Shuttle."

Re: SpaceX BFR [video]

#169

Post by dzhiurgis »

icc97 wrote: post #124
krisroadruck wrote: post #111

Earlier quoted context omitted.

Total Time is only one portion of the suckage of air travel though. It's that long window of time where you are cramped in a small seat, potentially with large strangers spilling into your space from either side that I dislike the most. If I only have to deal with that bit for 30 minutes, the rest of the trip can take as long as it reasonably wants.

No more deep vein thrombosis. Or screaming kids kicking the back of your chair cause they've got nothing to do for 10 hours. London to Sydney would be a massive improvement because often you have to stop halfway. Plus you get all the benefits of paying for a Virgin Galactic trip

Auckland to Vilnius is at least 3 flights and 24+ hours of flight time. Door to door is basically 2 days. Elon please save me.

Re: SpaceX BFR [video]

#170

Post by cycrutchfield »

codeulike wrote: post #101

Cost per seat should be about the same as full fare economy in an aircraft. Forgot to mention that. - Elon https://www.instagram.com/p/BZnVfWxgdLe/ Looks like fun. I'd love to see the in-flight safety video! "Make sure there's nothing in your pockets because we'll be hitting 3 Gees. If anything goes wrong, we're all probably toast." I think this was just an interesting idea thrown out at the end of a talk that had mu…

Note that the Instagram post is a little misleading. “Full Fare economy” is not as cheap as you think, it’s more like what you would pay for business class. So, maybe $3k for a transatlantic flight.
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