Momentum is building to explore Venus • Hacker News Board

Re: Momentum is building to explore Venus

#141

Post by colordrops » Fri, Jun 07, 2019, 4:12 AM UTC

Baeocystin wrote: post #125

colordrops wrote: post #112

Earlier quoted context omitted.

You can live there long term since there is gravity.

Is Mars' gravity too low for long-term habitation? I know that we know that zero-G is a negative, but do we have any idea if it's a threshold that needs to be reached, a linear response to G-force that scales from untenable to fine, etc?

I would imagine that it's going to be a gradient. Just like any other form of exercise, the more effort you put in, the more positive effect. Humans would need to put in much less effort on Mars. Once we are spread across the solar system there will probably new exercise systems for 0 and .3 G environments.

Re: Momentum is building to explore Venus

#142

Post by taneq » Fri, Jun 07, 2019, 4:59 AM UTC

sandworm101 wrote: post #83

CodiePetersen wrote: post #40

Earlier quoted context omitted.

I think upper atmosphere study would be great. There are some colony designs that suggest an oxygen filled colony would float at earth pressure. And with the sulfuric acid and co2 you have everything you need to make water air and fuel. Not to mention protection from asteroids and deadly rays. It would be a challenge but all of the planets and other bodies present their own challenges.

At the same ambient pressure, an O2 would float, but just barely. It wouldn't float like a hydrogen/helium balloon does on earth. If the pressure is the same on either side of the balloon, lift comes from different atomic weights of the gasses. Helium weights much less than air. But the O2 inside the Venus habitat doesn't weigh all that much less than the CO2 outside. As a practical matter, you would probably need li…

> No balloon can float in a sea of hydrogen.

You could use a hot hydrogen balloon.

https://en.m.wikipedia.org/wiki/A_Meeting_with_Medusa

Re: Momentum is building to explore Venus

#143

Post by User23 » Fri, Jun 07, 2019, 5:00 AM UTC

SaberTail wrote: post #54

I'm glad Venus is getting more attention. Mars seems to get the most attention as a place to visit, but we seem to ignore Venus. Venus has a few things going for it that I think make it a better choice for permanent human habitation than Mars. * Venus has nearly Earth-like gravity (8.9 m/s² instead of 9.8 m/s²) * The atmosphere 50 km above the surface is the right temperature for liquid water, and has a similar atmos…

I’m going to go out on a limb and guess that Venus’s high temperatures might be determined by solar radiation and the inverse square law and that its atmosphere is on the consequence side of the expression.

That said I entirely agree we should be exploring it!

Re: Momentum is building to explore Venus

#144

Post by User23 » Fri, Jun 07, 2019, 5:03 AM UTC

autokad wrote: post #118

mandevil wrote: post #91

Earlier quoted context omitted.

The Soviet Union always put more attention on Venus, and the US more on Mars. From what I can tell this dates back to before there were actual space programs, so I strongly suspect this has to do with the science fiction in the respective languages. For example in H.G. Wells 1898 War of the Worlds, the bad guys are from Mars, Edgar Rice Burroghs John Carter series is about Mars, etc. whereas engineer cosmonaut Konsta…

i think the primary reason for US interest in mars is due to the fact that it is much more likely that mars #1) previously contained life and #2) we will be able to find evidence of #1 on mars, vs venus.

The cloud cover on Venus is so thick it could contain life right now. The belief that it’s necessarily barren due to extreme conditions predates the widespread knowledge of extremophile earthbound life. If you gave me better than even odds that there is life on Venus I’d take them.

Re: Momentum is building to explore Venus

#145

Post by ryacko » Fri, Jun 07, 2019, 5:10 AM UTC

hathawsh wrote: post #68

modzu wrote: post #63

Earlier quoted context omitted.

well you said it: we know exactly how to heat up mars (greenhouse gases) but its not so clear how to cool down venus. also mars has water.

We don't need to cool it down. We could float a platform about 49.5 km above the surface of Venus, where the temperature and pressure nearly match the earth at sea level. To launch a probe, we could simply drop it from the platform. This article about Venus is very enlightening: https://en.wikipedia.org/wiki/Atmosphere_of_Venus

Have you heard of Murphy's law?

Floating above Venus provides the benefits of a gravity well, but there's the danger of sudden buoyancy loss.

Re: Momentum is building to explore Venus

#146

Post by cpv » Fri, Jun 07, 2019, 5:21 AM UTC

mandevil wrote: post #91

SaberTail wrote: post #54

I'm glad Venus is getting more attention. Mars seems to get the most attention as a place to visit, but we seem to ignore Venus. Venus has a few things going for it that I think make it a better choice for permanent human habitation than Mars. * Venus has nearly Earth-like gravity (8.9 m/s² instead of 9.8 m/s²) * The atmosphere 50 km above the surface is the right temperature for liquid water, and has a similar atmos…

The Soviet Union always put more attention on Venus, and the US more on Mars. From what I can tell this dates back to before there were actual space programs, so I strongly suspect this has to do with the science fiction in the respective languages. For example in H.G. Wells 1898 War of the Worlds, the bad guys are from Mars, Edgar Rice Burroghs John Carter series is about Mars, etc. whereas engineer cosmonaut Konsta…

Here is a book from the soviet era, about Venus

https://www.goodreads.com/book/show/23302599

"Тайна утренней зари"/"The Mystery of the Dawn"/"Taina Luceafărului".

As for their space program, I do believe they had almost similar investment for Venus and Mars, just Venus was more approachable and the missions were more fruitful(?). They canceled some Mars and Venus programs in time. Some wikipedia page about USSR space program:

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

Re: Momentum is building to explore Venus

#147

Post by ncmncm » Fri, Jun 07, 2019, 5:24 AM UTC

aeternus wrote: post #108

yholio wrote: post #88

Earlier quoted context omitted.

By attaching it to a steel balloon filled with breathing gas, which can provide lift in the Venusian atmosphere. Inside the baloon you get a really nice habitat with the correct Temperature, pressure and gas composition for humans to live in.

Other than a basically unlimited supply of CO2 however, what would the advantage be compared to a just a space station? With Mars, you can mine building materials from the surface.

CO2 has carbon in it. Strip off the oxygen to breathe, the rest makes very strong building material.

Attach hydrogen, you get rocket fuel. Or plastic. Bind in some nitrogen, you can have proteins. There is probably silane lower down; send down a balloon to collect it, for silicon. Or all the way to the surface, to collect rocks.

Nuke power is totally practical there; no shielding needed, or worry about leaks; you just hang it a mile below your living-space balloons.

Re: Momentum is building to explore Venus

#148

Post by ncmncm » Fri, Jun 07, 2019, 5:26 AM UTC

djakjxnanjak wrote: post #86

stickydink wrote: post #80

Earlier quoted context omitted.

How would we float a platform at that height?

We can float things in the earth atmosphere at sea level. My completely ignorant prior is that we should be able to do it there too, if the temp and pressure are the same.

Much better: the air at normal pressure is much denser, so ordinary breathing air supports a balloon.

Re: Momentum is building to explore Venus

#149

Post by ncmncm » Fri, Jun 07, 2019, 5:43 AM UTC

cr0sh wrote: post #79

mirimir wrote: post #34

Earlier quoted context omitted.

I see no reason why intelligent life with high technology could not have developed on Venus. Say, several hundred million years ago. And perhaps they triggered runaway greenhouse warming, which vaporized the oceans. And so perhaps it was the loss of the oceans that ended plate tectonics, not the other way around. I doubt that runaway greenhouse warming could get so extreme for Earth. I recall reading that solar input…

> I see no reason why intelligent life with high technology could not have developed on Venus. Say, several hundred million years ago. And perhaps they triggered runaway greenhouse warming, which vaporized the oceans. And so perhaps it was the loss of the oceans that ended plate tectonics, not the other way around. The only way that thought experiment could make sense is if they had the technology to do that, but not…

Who says they didn't escape to Earth, a billion years ago?

It's not as if they would still be around ... unless they live at the sea bottom; then there is no reason we would know.

"Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn."

"In his house at R'lyeh dead Cthulhu waits dreaming."

But seriously, an invasion from Venus a billion years ago would leave no evidence we could reconstruct today. After they went extinct, less than a million years later, their microbes would remain. And eventually become us.

Re: Momentum is building to explore Venus

#150

Post by killjoywashere » Fri, Jun 07, 2019, 6:07 AM UTC

29athrowaway wrote: post #139

SaberTail wrote: post #54

I'm glad Venus is getting more attention. Mars seems to get the most attention as a place to visit, but we seem to ignore Venus. Venus has a few things going for it that I think make it a better choice for permanent human habitation than Mars. * Venus has nearly Earth-like gravity (8.9 m/s² instead of 9.8 m/s²) * The atmosphere 50 km above the surface is the right temperature for liquid water, and has a similar atmos…

Venus is closer to Earth.

Given a choice of death by fire and death by cold, death by cold is easier to mitigate against, and is the default problem in space. To survive Venus, you have to first survive the freezing trip to Venus. So you need heating and air conditioning. A lot. Of both.

On Mars, you only need the heating systems that got you to Mars.

Similar problem for radiation: going to Mars leads to less radiation. Going to Venus increases radiation. So in Venus orbit, you need more shielding than you need at low Earth orbit. On Mars, you need less.

There's another commentor suggesting floating in steel balloons. Um, weather is going to be rough. Really, really rough. The mass of building materials necessary to survive the storms strikes me as likely deal-breaker. Never mind the complete lack of light.

I don't know if everything is harder on Venus, but most of the first-order issues are substantially harder.