Why Spaceflight Will Never Be as Safe as Modern Aviation | Hacker News Reader

Why Spaceflight Will Never Be as Safe as Modern Aviation

nautil.us

13 pointsdnetesn20 comments

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?

  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.

What about per hour?

>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.

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-...

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.

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.

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.

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.

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.

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.

Obviously with current rockets, it's necessary for that energy to be expended nearly all at once (8-12 minutes). But is that a law of nature or just a drawback of current technology? In other words, could you travel slowly into space?

You have to reach escape velocity to get out of earth, so you can't be that slow.

Also, the distances are so great that "travelling slowly" is not very convenient anyway.

Sure, if you use a space elevator. http://en.wikipedia.org/wiki/Space_elevator

This won't get you out of Earth orbit, though. If you want to go to other planets, you have no choice other than reaching escape velocity.

However, once in orbit, I'm pretty sure you can reach escape velocity as gradually as you want. You'd just gradually increase your orbit's apogee until you stop orbiting.

Because space.

Getting to it, and returning from it, is inherently more dangerous than not going that far, across those kinds of boundaries, and returning. I don't think it's an issue of power, but the nature of what that power is being used for.

I tend to agree. An analogous article title might be, "Why deep-ocean submersibles will never be as safe as cruise lines."

Never say never. Most accidents happen during launch and re-entry. Once you are in space the potential for accidents is smaller. The accident rate should drop if we built a space elevator. Energy expenditure too.

Someone has forgotten a prime lesson from Mary Poppins: never say never.

That was my first reaction: the title could be better rephrased "I can't figure out how space flight will be safer than modern aviation". I'll eat my hat if that turns out to be true.

But, we're going to run out of steam with technology at some point. In this modern world it feels like progress is the only constant, but eventually, we're actually going to run up against physical limits and figure out optimal configurations of atoms for particular tasks.

In other words, we're on an S curve, but it looks very exponential from our perspective.

Of course, I'd be shocked if the optimal configuration of atoms for launching humans in to space ever has a fatality, without being caused by some kind of event that also wipes out earth in the process.

In other words, in the long run, it's well worth the risk trying to get off of the planet, because the planet is doomed.

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