The oceans are very hostile to humans too, really not much less than space, and a lot of ocean-going vessels are rusty hulks.

A lot of ocean going vessels were literally made from wood that was continuously rotting.

A naked human can survive the ocean for 3 orders of magnitude longer than they can survive space.

Calm ocean, yes.

The real problem are the storms, as a naked human you won't survive in an ocean storm any longer than in vacuum.

At least you are going to space in a sophisticated vessel full of redundant life support systems. People sailed the high seas in old, barely seaworthy wooden ships dangerously overloaded with cargo, which didn't even have a reliable way of determining where precisely they were, because no one could tell longitude at sea before the mid-1700s or so.

Didn't they die by the droves?

In fact, they did. Being a sailor was about the most dangerous profession that you could choose, including the military.

Until today, some jobs at sea are pretty dangerous. Being a fisherman in Alaskan waters is much more risky than being an (American, not Russian) soldier.

People still do it. Which convinces me that people will risk their lives going to Mars, and more than a few of them. Some people are just built that way.

People risk their lives for high-risk, high-reward jobs. They don't risk their lives for high-risk, no-Reward explorations.

Do you believe that no one feels highly rewarded by exploring wilderness?

Generations of explorers, many of whom lost their lives for no gain, indicate otherwise.

Let us make a thought experiment. Let's say that Musk, tomorrow, declares "we are now creating a list of future Mars colonists, reasonably healthy individuals under 70 can apply from anywhere in the world, please send us your resumes".

Would they get fewer than 10 million applicants? I'd rather guess 50 million or so. Of course, some of those are going to get cold feet the moment they receive their one-way flight ticket in mail, but quite a few won't.

By your hypothesis, there would be approximately zero applicants. I don't believe that.

I guess there'd still be. Finding one that's also competent enough to be trusted to lead the mission will be quite hard tho.

You know we generally have those adrenaline junkies lead most missions? Apollo 17 was literally the first Apollo mission NOT led by a test pilot.

> They don't risk their lives for high-risk, no-Reward explorations.

Sure they do. There’s a queue at the top of Mount Everest despite regular deaths; a couple rich folk got squished to pulp in the Titanic submarine last year. The free solo guy climbs Yosemite for the fun of it.

Plenty of people still have that itch.

This is ridiculous. People risk their lives for pretty views and brief moments of adrenaline. I would advise you to touch grass, but you might not want to risk a cut.

Up until 90s or so more people been on moon surface than sailed around world non-stop single handed.

Now it’s a race every few years - Vendee Globe. Something like half do not finish.

That's more an argument for redundant doors than perfect doors, though.

I think the definition of workable old ship is going to be different in space, but ultimately you can expand workable envelope for it by over-engineering critical parts. That's kind of what I mean. Right now we don't quite know how to do that efficiently or effectively.

Still remember that at one time moving faster than 15mph was considered insane and pushed the limits of materials and vehicle design. Same for high altitude flight, McMurdo station, deep ocean diving, etc.

In a lot of ways very deep ocean diving is harder than space. The pressure differentials are a lot worse.

The hard part about space is really launch and delta-V budgets.

No, that's the point: It's a significant technological advancement for some unreliability/imprecision to not mean critical failure.

So how can that work for air seals? Have a big robust air storage that can replenish losses from your half-broken door? How many other systems like that do we need? And all that extra weight somehow doesn't get you stranded in space when your badly maintained, low efficiency engine can't move it and your payload with the fuel that fits in the tanks? I get the principle, it just seems literally impossible to achieve (without, maybe, a radical step forward from chemical propulsion).

Same way rusty old cargo ships keep the sea out. Redundancy. Compartments. Emergency doors that close. Crew that run around patching leaks. Spare parts and welding equipment.

The ISS leaks air on a daily basis.

Everything's relative. People a century ago would probably have felt uncomfortable at the idea of DIYing a multi ton vehicle being accelerated by a extremely high power pistons pounding up and down thanks to creating a controlled explosion inside a tight little box, that you can then hop in and cruise around at 80MPH+. And indeed if something goes critically wrong, you're dead. We just work to reduce the number of ways that things can go critically wrong.

I think a century or longer ago, they wouldn't care. It was already pretty easy to fall off a horse and die.

I can't find the details now bit in the early 19th century an MP introduced a bill to parliament to make it illegal for trains to go over 30mph because in his opinion it would be impossible to breath at that speed.

Although space flight tends to have long periods of time where the craft can just coast. You have time to work the problem. A complete system failure could be worse on a plane in cloud than a spacecraft in orbit.

That's more of a movie trope. The ISS has had leaks, they are not explosive decompression. It makes sense too, the pressure vessel only has to hold in 1 atm, and we can manage to breathe a lot less than that.