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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 &

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. Loss rate for manned rocket launches [1]: 0.79% Loss rate for unmanned rocket launches [1]: 6.68% Rate of airplane crashes with at least one fatality [2]: < 0.00004% Even if SpaceX is able to make manned space flight 10x safer, I'm not sure I'd trade 19 of the 20 hours I spent traveling from LA to South Africa this summer for a 1/1,300 chance of blowing up during launch. [1] https://space.stackexchange.com/a/12229 https://space.stackexchange.com/a/12229 [2] http://www.planecrashinfo.com/cause.htm http://www.planecrashinfo.com/cause.htm

cjsuk 9y ago
It's less likely and a far better way to go than cancer :)
Robotbeat 9y ago
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 data to work with (especially when combined with near-misses) allowing you bring the relative failure rate very low. Increase flight rates by 5 orders of magnitude, and you may be able to increase reliability by, say, 4 orders of magnitude.
- thesash 9y ago
  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.
  - ncallaway 9y ago
    > 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.
    - thesash 9y ago
      What am I missing that addresses the math?
      - Cerium 9y ago
        That you will always have at least single digit failures. Sometimes things have to go wrong before we can correct them. We got where we are today with airplanes not because the first million flights didn't have a single accident, but because we paid careful attention to every failure and did our best to keep it from ever happening again. Take a look at this report on Boeing crash history: http://www.boeing.com/resources/boeingdotcom/company/about_bca/pdf/statsum.pdf http://www.boeing.com/resources/boeingdotcom/company/about_b... In particular, take a look at page 17 (slide 16) which shows the crash rate over time. We have gone from about 40 hull losses per million departures in the 50's to about 0.6 to 1 (depending on how you count) per million departures today.
  - agildehaus 9y ago
    Most (all?) of that rate provided by the shuttle program and by early vehicles from the 60s and 70s. Mercury + Gemini + Apollo had a 0% death rate in-flight. Not that they didn't come very close. The shuttle had numerous design flaws. The use of solid fuel. A booster that was assembled in seven different sections, fastened, and sealed with rubber o-rings. Go-fever. Foam insulation that was known to fall off and strike the orbiter during launch. Not that space flight isn't dangerous. My point is we can do a lot better with proper designs and attitudes. SpaceX also gets to examine and improve their stages in a way that has never been possible now that they come back in one piece.
- simplicio 9y ago
  The problem is that to increase flight rates by 5 orders of magnitude, you need demand to increase by that much. And people are unlikely to demand rocket flights until after they're as safe as plane flights. Early passenger planes were pretty dangerous to, but they got around the above problem by a) being much faster than trains, making the risk worth it, b) having clear military applications, the military being less worried about losing the occasional aircrew. I don't really see how SpaceX gets around that chicken and egg problem.
  - Robotbeat 9y ago
    They're going to get around it because this is a secondary market for BFR. Primary market is launching satellites (especially their constellation). Remember, this point-to-point idea was basically an after-thought. It's decades away, but the rocket will be launching within the next 3-5 years. So they'll have decades to get it right, and the manufacturing line and much of the infrastructure will be paid for. But you're right about demand. The biggest economic problem is that it's too big. Each BFR needs 1000 passengers. To be economic, it needs to fly multiple times per day, so each BFR needs to fly like a million people every year. Look around to how many people fly long-haul, and you saturate the existing market VERY quickly. BUT the world is getting richer. Soon (50-80 years?), there will be 5-10 billion middle class folk in the world, an order of magnitude more than now. And if the time for travel can be cut short like this, then you should have some demand induction taking place. So maybe it'd start making economic sense. There is a fundamental advantage for BFR versus existing aircraft: SpaceX is able to make Falcon 9s and probably BFRs for about the same cost (a little less, actually) per unit dry mass as a 737 or 777 or A380. But a BFR can do trips that'd last 15 hours in a 777 or A380 in less than 1 hour. That means you can do 10 times as many trips, cutting your amortization time and crew hours by an order of magnitude. But that depends on having enough demand, which is pretty questionable except in the long-term.
    - simplicio 9y ago
      Total orbital rocket flights/yr are usually considerably less than 100 though, so I'm sceptical they'll ever approach airplane reliability with so few flights. Honestly, that's kind of why the BFR idea kind of worries me. It feels like SpaceX analysed the need for orbital space-flights, and realized there was unlikely to ever be the kind demand that would provide the economies of scale needed to do what they want. On the otherhand, there's undeniably a large demand for terrestrial travel, so they came up with a way to use rockets for that purpose. It feels like something to show investors, rather than a workable plan. But hopefully I'm wrong. Economics aside, its certainly cool, and it would be nice to have an application for terrestrial missiles other than nuclear annihilation.
dvdhnt 9y ago
In the video, Musk states that SpaceX believes BFR will match the safety of commercial airliners due to its multi-engine propulsive landing capability.
- thesash 9y ago
  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.
  - sillysaurus3 9y ago
    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.
    - thesash 9y ago
      Again, I'm not saying it's not possible I'm saying that it's going to be really, really hard and that saftey is the critical path to making this viable. I'm sure they are spending all of their time and resources devoted to improving saftey. I'm just pointing out the ridiculousness of focusing the PR on time savings and cost parity when the saftey deficit is currently massive.
    - nradov 9y ago
      Fair has nothing to do with it. Civilians aren't going to pay for tickets on a rocket that they perceive as unsafe just to save a few hours. Those rockets will have to go years carrying cargo (or maybe military personnel) with zero crashes before the FAA will be willing to certify them for carrying paying commercial passengers.
  - 9y ago
grey-area 9y ago
Reusability and greater frequency will change these calculations radically. Similar statements to yours were made about flight in early airplanes, which was also dangerous.
justin66 9y ago
> 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."
- thesash 9y ago
  Loss rate for Space Shuttle program was 1.5% 135 missions, 2 lost. http://www.popularmechanics.com/space/a6611/us-space-shuttle-program-by-the-numbers/ http://www.popularmechanics.com/space/a6611/us-space-shuttle...
  - justin66 9y ago
    Do you see that as an indictment of the safety of manned space flight, or the safety of that vehicle? (you do understand that the modern Soyuz is quite safe, right? One can expect SpaceX's stuff to be safer.)
- planteen 9y ago
  Are you looking at failures per mission or fatalities per person-trip? I thought the shuttle and Soyuz were very close on the fatalities per person-trip metric.
  - justin66 9y ago
    I'm surprised by that. They haven't lost a Soyuz crew since 1971, and they've flown quite a few. (Soyuz capsules have had one or two pretty hard landings that I'm aware of. That's a failure mode that the newer capsules probably won't have.)
    - planteen 9y ago
      I can't quickly find a source, but back of the envelope is there have been 134 Soyuz manned missions. The number of people varies 1-3, most often 3 but occasionally 2. There were 135 Shuttle manned missions. Number there varied between 2-7, but ballpark looks like 6 was common. So if we say 3 x 134 on Soyuz, there are 402 person-trips and 6 x 135 on Shuttle it is 810 person-trips. There were 4 Soyuz fatalities and 14 on the shuttle. So Soyuz fatality rate is about 1/100 and the shuttle is 1/56. So maybe it is closer to a factor 2 of difference. The fatal mission rate is nearly identical (both have 2 fatal missions each). https://en.wikipedia.org/wiki/List_of_Russian_manned_space_missions https://en.wikipedia.org/wiki/List_of_Russian_manned_space_m... https://en.wikipedia.org/wiki/List_of_Soviet_manned_space_missions https://en.wikipedia.org/wiki/List_of_Soviet_manned_space_mi... https://en.wikipedia.org/wiki/List_of_Space_Shuttle_missions https://en.wikipedia.org/wiki/List_of_Space_Shuttle_missions
Florin_Andrei 9y ago
> 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. It's a valid concern, but it's only a matter of time before each new technology is perfected and made safe. The exact same debates took place when Stephenson built his locomotive.

cjsuk 9y ago

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

Robotbeat 9y ago

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 data to work with (especially when combined with near-misses) allowing you bring the relative failure rate very low. Increase flight rates by 5 orders of magnitude, and you may be able to increase reliability by, say, 4 orders of magnitude.

thesash 9y ago
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.
- ncallaway 9y ago
  > 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.
  - thesash 9y ago
    What am I missing that addresses the math?
    - Cerium 9y ago
      That you will always have at least single digit failures. Sometimes things have to go wrong before we can correct them. We got where we are today with airplanes not because the first million flights didn't have a single accident, but because we paid careful attention to every failure and did our best to keep it from ever happening again. Take a look at this report on Boeing crash history: http://www.boeing.com/resources/boeingdotcom/company/about_bca/pdf/statsum.pdf http://www.boeing.com/resources/boeingdotcom/company/about_b... In particular, take a look at page 17 (slide 16) which shows the crash rate over time. We have gone from about 40 hull losses per million departures in the 50's to about 0.6 to 1 (depending on how you count) per million departures today.
- agildehaus 9y ago
  Most (all?) of that rate provided by the shuttle program and by early vehicles from the 60s and 70s. Mercury + Gemini + Apollo had a 0% death rate in-flight. Not that they didn't come very close. The shuttle had numerous design flaws. The use of solid fuel. A booster that was assembled in seven different sections, fastened, and sealed with rubber o-rings. Go-fever. Foam insulation that was known to fall off and strike the orbiter during launch. Not that space flight isn't dangerous. My point is we can do a lot better with proper designs and attitudes. SpaceX also gets to examine and improve their stages in a way that has never been possible now that they come back in one piece.
simplicio 9y ago
The problem is that to increase flight rates by 5 orders of magnitude, you need demand to increase by that much. And people are unlikely to demand rocket flights until after they're as safe as plane flights. Early passenger planes were pretty dangerous to, but they got around the above problem by a) being much faster than trains, making the risk worth it, b) having clear military applications, the military being less worried about losing the occasional aircrew. I don't really see how SpaceX gets around that chicken and egg problem.
- Robotbeat 9y ago
  They're going to get around it because this is a secondary market for BFR. Primary market is launching satellites (especially their constellation). Remember, this point-to-point idea was basically an after-thought. It's decades away, but the rocket will be launching within the next 3-5 years. So they'll have decades to get it right, and the manufacturing line and much of the infrastructure will be paid for. But you're right about demand. The biggest economic problem is that it's too big. Each BFR needs 1000 passengers. To be economic, it needs to fly multiple times per day, so each BFR needs to fly like a million people every year. Look around to how many people fly long-haul, and you saturate the existing market VERY quickly. BUT the world is getting richer. Soon (50-80 years?), there will be 5-10 billion middle class folk in the world, an order of magnitude more than now. And if the time for travel can be cut short like this, then you should have some demand induction taking place. So maybe it'd start making economic sense. There is a fundamental advantage for BFR versus existing aircraft: SpaceX is able to make Falcon 9s and probably BFRs for about the same cost (a little less, actually) per unit dry mass as a 737 or 777 or A380. But a BFR can do trips that'd last 15 hours in a 777 or A380 in less than 1 hour. That means you can do 10 times as many trips, cutting your amortization time and crew hours by an order of magnitude. But that depends on having enough demand, which is pretty questionable except in the long-term.
  - simplicio 9y ago
    Total orbital rocket flights/yr are usually considerably less than 100 though, so I'm sceptical they'll ever approach airplane reliability with so few flights. Honestly, that's kind of why the BFR idea kind of worries me. It feels like SpaceX analysed the need for orbital space-flights, and realized there was unlikely to ever be the kind demand that would provide the economies of scale needed to do what they want. On the otherhand, there's undeniably a large demand for terrestrial travel, so they came up with a way to use rockets for that purpose. It feels like something to show investors, rather than a workable plan. But hopefully I'm wrong. Economics aside, its certainly cool, and it would be nice to have an application for terrestrial missiles other than nuclear annihilation.

dvdhnt 9y ago

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

thesash 9y ago
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.
- sillysaurus3 9y ago
  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.
  - thesash 9y ago
    Again, I'm not saying it's not possible I'm saying that it's going to be really, really hard and that saftey is the critical path to making this viable. I'm sure they are spending all of their time and resources devoted to improving saftey. I'm just pointing out the ridiculousness of focusing the PR on time savings and cost parity when the saftey deficit is currently massive.
  - nradov 9y ago
    Fair has nothing to do with it. Civilians aren't going to pay for tickets on a rocket that they perceive as unsafe just to save a few hours. Those rockets will have to go years carrying cargo (or maybe military personnel) with zero crashes before the FAA will be willing to certify them for carrying paying commercial passengers.
- 9y ago

grey-area 9y ago

Reusability and greater frequency will change these calculations radically. Similar statements to yours were made about flight in early airplanes, which was also dangerous.

justin66 9y ago

> 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."

thesash 9y ago
Loss rate for Space Shuttle program was 1.5% 135 missions, 2 lost. http://www.popularmechanics.com/space/a6611/us-space-shuttle-program-by-the-numbers/ http://www.popularmechanics.com/space/a6611/us-space-shuttle...
- justin66 9y ago
  Do you see that as an indictment of the safety of manned space flight, or the safety of that vehicle? (you do understand that the modern Soyuz is quite safe, right? One can expect SpaceX's stuff to be safer.)
planteen 9y ago
Are you looking at failures per mission or fatalities per person-trip? I thought the shuttle and Soyuz were very close on the fatalities per person-trip metric.
- justin66 9y ago
  I'm surprised by that. They haven't lost a Soyuz crew since 1971, and they've flown quite a few. (Soyuz capsules have had one or two pretty hard landings that I'm aware of. That's a failure mode that the newer capsules probably won't have.)
  - planteen 9y ago
    I can't quickly find a source, but back of the envelope is there have been 134 Soyuz manned missions. The number of people varies 1-3, most often 3 but occasionally 2. There were 135 Shuttle manned missions. Number there varied between 2-7, but ballpark looks like 6 was common. So if we say 3 x 134 on Soyuz, there are 402 person-trips and 6 x 135 on Shuttle it is 810 person-trips. There were 4 Soyuz fatalities and 14 on the shuttle. So Soyuz fatality rate is about 1/100 and the shuttle is 1/56. So maybe it is closer to a factor 2 of difference. The fatal mission rate is nearly identical (both have 2 fatal missions each). https://en.wikipedia.org/wiki/List_of_Russian_manned_space_missions https://en.wikipedia.org/wiki/List_of_Russian_manned_space_m... https://en.wikipedia.org/wiki/List_of_Soviet_manned_space_missions https://en.wikipedia.org/wiki/List_of_Soviet_manned_space_mi... https://en.wikipedia.org/wiki/List_of_Space_Shuttle_missions https://en.wikipedia.org/wiki/List_of_Space_Shuttle_missions

Florin_Andrei 9y ago

> 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. It's a valid concern, but it's only a matter of time before each new technology is perfected and made safe. The exact same debates took place when Stephenson built his locomotive.