Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

SpaceX BFR [video]

youtube.com

Post reply on HN
Print view View original

151–160 of 277 posts

Re: SpaceX BFR [video]

#151

Post by thesash »

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]: 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

[2] http://www.planecrashinfo.com/cause.htm

Re: SpaceX BFR [video]

#153

Post by Robotbeat »

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…

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.

Re: SpaceX BFR [video]

#154

Post by dvdhnt »

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…

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

Re: SpaceX BFR [video]

#155

Post by thesash »

Robotbeat wrote: post #153
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…

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.

Re: SpaceX BFR [video]

#156

Post by davedx »

idlewords wrote: post #121
drcross wrote: post #104

Earlier quoted context omitted.

It would be different if this was coming from the mouth of the Comcast CEO but it's coming from Musk who has a series of successful achievements of his own, a profitable space company with the worlds first re-usable rockets, the first company to successfuly market an electric car, fastest growing battery storage solution on the market. These things matter.

They do, but the crux of every Musk fantasy is a radical drop in the cost of these things, a promise he has never delivered on.

Roadster: 110k

Model S: 70k

Model 3: 35k

Re: SpaceX BFR [video]

#157

Post by thesash »

dvdhnt wrote: post #154
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…

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.

Re: SpaceX BFR [video]

#158

Post by grey-area »

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…

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

Re: SpaceX BFR [video]

#159

Post by modeless »

rkangel wrote: post #38
ascorbic wrote: post #26

Earlier quoted context omitted.

"About the same as full fare economy" So in the low thousands. Incredible if true. https://www.instagram.com/p/BZnVfWxgdLe/

Impressive if they achieve that. The price point they need to reach though for this to be feasible is business class. As suggested by the NY Shanghai route in the video, the major use for this would be distant business meetings that either have to be week long trips or video conferences. Instead they could be overnight or even day trips. Businesses have more buying power as well compared to consumers.

Business class isn't low enough. This thing has A380 passenger capacity and you can't fill an A380 with business class, there aren't enough rich people. You need economy.

Re: SpaceX BFR [video]

#160

Post by mrec »

mtgx wrote: post #85
willyt wrote: post #53

Earlier quoted context omitted.

And if it becomes that common, in 150 years time, New York will be under water. I remember reading that the instantaneous power output of one Apollo rocket taking off is roughly the equivalent of the entire average electricity load of the UK. Surely burning a country's worth of rocket fuel every time you want to travel long distance is not sustainable?

Fusion power can't come soon enough. Maybe it's time for Musk to start working on that. He actually said in an older interview that he would like to tackle it eventually.

Fusion power doesn't really help with rocketry, though.
Post reply on HN