On: Why Spaceflight Will Never Be as Safe as Modern Aviation

[Gravityloss]

The article makes a case that large energies are needed and insinuates that it's necessarily unsafe.

The power per passenger in a jet is about ten fold compared to a car, where it is perhaps ten fold compared to riding a horse which might be ten fold compared to bicycling.

Which do you think is safest, and why?

[Retric → Gravityloss]

  Per trip walking, bicycling, horse, car, airplane, space shuttle.
  Per mile space shuttle, airplane, car, horse, bicycling, walking.

The shuttle is a great example of that relative trend. 2 accidents over 537,114,016 miles vs 2 accidents per 134 flights. Though commercial airplanes are fairly safe private planes are little better than cars.

[Gravityloss → Retric]

I think bicycles are less safe than cars even per trip, because in a bicycle-car collision the bicyclist always fares worse.

The point was to illustrate that it's not some uncontrollable law of nature that more energy / power yields less safety.

[Retric → Gravityloss]

Your assigning deaths caused by cars to bickes.

Your also assuming all trips are in mixed traffic.

And then without looking up any statistics you assume your correct.

...

I don't know where to begin.

[Gravityloss → Retric]

http://en.wikipedia.org/wiki/Aviation_safety#Comparison_to_o...

In this table, bicycling has 170 deaths per billion journeys while flying has 117 and cars 40.

Different countries have different safety numbers for various reason. For example bicycling tends to be safer the more there is of it.

[Retric → Gravityloss]

That chart is using 15 year old numbers because recent history is less flattering. Strictly speaking the

International Space Station is the safest way to travel, 17,150 mph, and zero deaths. Further, Deaths per billion journeys:

Car: 40 Foot: 40

But wait, more people are ~8x as many people are killed in cars vs walking in the US. So you only walk somewhere every few days?

Let's sanity check that: 1.24 million deaths occurred on the world’s roads. 7 billion people let's say they all average 2 trips a day * 365 days a year. That's ~485 deaths per billion trips.

Ok, so that chart is pure B.S.

[Gravityloss → Retric]

I think some countries have orders of magnitude worse road safety, as the USA too had in the past.

On the other hand, most of the world's population doesn't drive a car so the number of trips is probably a lot less, making the number higher.

I think you have good points but your somewhat aggressive style is unnecessary.

[coldtea → Retric]

>Though commercial airplanes are fairly safe private planes are little better than cars.

I think per mile, commercial planes is about 2x as safe as cars -- not that much better as believed.

[pkroll → coldtea]

According to Airline Reporter[1], per 100 million miles there are 1.33 deaths by auto, and .0077 deaths by commercial plane. Though it's over a limited amount of time...

[1]http://www.airlinereporter.com/2010/09/flying-is-safe-and-i-...

[Retric → pkroll]

That's terrible comparison, commercial aviation tents to exclude 9/11 and bystander deaths along with private flights while looking vs all car trips. A much better comparison would be to busses which are much safer.

Anyway, getting an apples to apples comparison between different modes of travel is almost impossible which was my original point.

[TheLoneWolfling → Retric]

What about per hour?