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Comment by hermitcrab | Hacker News Reader

>Sending a dudebro to mars would be much easier I think.

Indeed. The very low pressure on Mars (0.006 Bar) would be much easier to deal with than the absolutely crushing pressure on Venus (92 Bar) - not to mention the 470C surface temperature.

Hanggliding or ballooning in the cloud tops of Venus would be more practical than going to the surface.

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Humans have already survived simulated dives in hyperbaric chambers to around 70 bar with no long term effects, so in theory you may be able to have Venusian astronauts live in a habitat at ambient pressure if 90 bar is similarly tolerable (obviously would still need heroic measures for cooling, an approx. 200 K temperature differential is no joke). Getting enough gas there to pressurize the hab could be difficult, the deep dive experiments used a hydrogen/helium/oxygen mixture and I doubt you can recover helium through in situ resource extraction. And you would need some sort of acclimatization system to get the astronauts from their half-bar or so transit environment down to the surface - maybe a balloon that slowly descends over the period of a few days.

So yeah, pretty much science fiction for now!

>200 K temperature differential is no joke

It would be more like +450K/C difference (470C, not 470K).

Also it is one thing to get a person to 70 Bar in experimental conditions. It is another to actually stay at that pressure for prolonged periods and do anything useful.

Ah, whoops, you're right! Somehow my brain defaulted to Kelvin. So 740 K down to 290 K. Carnot COP alone is only around 65%, you'll be lucky to do half that, you need the stuff outside to survive heat and sulfuric acid, and you'll need to power it somehow. You could run it off a nuclear reactor, but your reactor will not be very efficient since it has to sink heat at over 700 K.

> Also it is one thing to get a person to 70 Bar in experimental conditions. It is another to actually stay at that pressure for prolonged periods and do anything useful.

Fully agreed - you'd have to test this long term in a hyperbaric habitat on Earth. You may end up needing some sort of medical or pharmaceutical intervention to make it possible. Very risky.

Even firmer in the realm of science fiction. It'd be a good hard sci-fi novel though.

It might be possible to make a hard suit where the inside is around 35 bar, which should be easier to work in (if maybe still uncomfortable), and reduce the stress on the suit of a 70 bar difference

Newtsuits have apparently been tested to 90 Bar:

https://en.wikipedia.org/wiki/Newtsuit

I believe they maintain ~1 Bar inside. Not sure if something like that could be built to protect a fragile human from the temperature differential, though. Better to send a robot?

That's exactly what I was thinking of, I just didn't know the name. If they can do 90 bar, that's fine too, I didn't know what pressures they were rated to

The article says they are rated to 30 bar, but have been tested to 90 bar. Presumably with no human inside for 90 bar!

>It'd be a good hard sci-fi novel though.

Must have been done already. Surely?

'Hail Mary' by Andy Weir has some interesting stuff about the (spoiler!) alien 'rocky' who is adapted to a high pressure/temperature environment.

I can't imagine anything would justify the cost and hellish conditions of living on Venus's surface. Except, perhaps, as an example what not to do to our own planet.

I really need to re-read Project Hail Mary, especially with the film in development. I really hope the film lives up to the book. I think they did a reasonably good job with The Martian, even though they cut out the entire dust storm section (and my favourite joke in the book!)

>I think they did a reasonably good job with The Martian

Within the time and marketing constraints of a Hollywood film, I thought they did a good job on 'The Martian'. Let's hope Hollywood doesn't ruin 'Hail Mary'.

I mean yeah, what can we do about that surface temperature? That is extremely high.

Refrigeration is hard but I don't think impossible at high ambient temperatures. What immediately comes to mind is compressing gas (which will increase its temperature), letting it equalise with the ambient temperature, then decompressing it, which will lower the temperature (from Charles' Law). No doubt there are many other systems that could be used though.

I'm not an expert on refrigeration at all, but if you're interested, it might be worth checking out the youtube channel Hyperspace Pirate, who does a lot of diy refrigeration systems, and I believe has managed to make liquid nitrogen in his garage using a home made refrigeration system. He also goes very in-depth into the technical details

Interesting, thank you!

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