Mars or venus?

[AHeroReborn]

Which planet should we be focusing our efforts on colonizing? 

Here are some pros and cons of both:

MARS city:

pros

• It's low gravity makes it easier to land on.
• ISRU refineries and 3d printers are viable there.
• big habitats can be constructed because of the low gravity.

cons:

• low gravity means any humans who want to return to earth must undergo therapy in some sort of gravity ring
• quite far away
• harsh storms

VENUS floating city:

pros:

• 90% of earths gravity means humans can ajust much easier.
• if cities floated in a specific layer of the atmosphere, it would be just the right temperature for humans while also allowing cities to use normal earth gases to float.
• abundance of carbon dioxide to be made into oxygen and rocket fuel.
• better sun exposure
• Closer to earth, requiring much less overall delta V.

cons:

• no hope of fabricating parts.
• probably more prone to failures.
• more expense per habitat module.

Edited October 9, 2017 by AHeroReborn

[Bill Phil]

Neither. No celestial body yet discovered is truly suitable for colonization.

Now, if we're talking about Mars or Venus being the only choices...? I'd prefer Mars, but Venus would make better sci fi.

You're also forgetting Delta-v to return. Taking off from Venus and entering a low orbit would take many km/s of Dv. Mars is just 4 and some change to orbit, not to mention the lack of a significant atmosphere can allow us to use EM catapults to take off.

The most I can see in the near future is bases on Mars, with bases in the Venusian sky eventually. Maybe colonies in the far flung future, but that's the far flung future.

[HebaruSan]

Twelve pages of discussion here, plus a poll:

I don't think "harsh storms" is accurate for Mars. For example, when the author of The Martian spoke at Google, he admitted outright that he falsified that part of his book to make the plot happen:

Spoiler

 

 

Edited October 8, 2017 by HebaruSan

[mikegarrison]

6 minutes ago, Bill Phil said:

The most I can see in the near future is bases on Mars, with bases in the Venusian sky eventually. Maybe colonies in the far flung future, but that's the far flung future.

Mars is too far to go to just for a "base". I do think the first people to visit it will be intending to come back, but either we will just give up on it (like we did the moon) or we'll start seeing people moving there with no intention of coming back.

[Bill Phil]

47 minutes ago, mikegarrison said:

Mars is too far to go to just for a "base". I do think the first people to visit it will be intending to come back, but either we will just give up on it (like we did the moon) or we'll start seeing people moving there with no intention of coming back.

It's not that far for a base at all. Even if it is, though, then that immediately rules out a colony. If it's too far for a base, it's much too far for a colony.

[NSEP]

Im not necessarily saying yes to Mars, but im saying no to Venus.

Building a base or even a colony in the air is hard, but is way harder and alot scarier when you litterly make people live a sustainable live right above literal HELL.

[NSEP]

3 hours ago, mikegarrison said:

Mars is too far to go to just for a "base".

No, its not. If you have a BFR like cargoship that could send for example 75 tons to Mars, you could easily make a base in one go. Im pretty sure 75 tons or maybe even less is enough to keep a few people alive for a couple of years, if they grew their own food with their hydroponic systems.

Its not about distane, its about how much you can send there and time.

Edited October 7, 2017 by NSEP

[DeltaDizzy]

4 hours ago, AHeroReborn said:

cons:

• low gravity means any humans who want to return to earth must undergo therapy in some sort of gravity ring
• harsh storms

It depends on what you mean by therapy. If you go with something similar to mars direct.

If so, then on the way back to earth, you can have it spin at  arate that generates 1g of gravity, or slowly increase the rate as you travel. This will make "Therapy" unnecessary.

 

The gravity on mars is about 1/3 of earths, which combined with the thinner atmosphere makes winds much lower.

[DAL59]

Mars storms are still 'harsh" in the sense that they hurt solar panels, but otherwise, they have little effect.  However, Venusian storms are really harsh- several hundred kilometers per hour.  However, it is constant, and a heavy airship wouldn't be pushed easily, especially if it is designed to be non-aerodynamic.  As for mining, blimp cities could lower tethered robots to quickly gather regolith, and then raise them for resource processing and repair.  Being able to EVA with just an oxygen mask and skin protection(maybe some kind of foam or just a normal wetsuit) is better.  

From a book I'm working on:

Spoiler

 

Some people questioned the sanity of Borromean Space Airships, the company that created the HAVACs.  After all, the surface of Venus is one of the only places where you can be burnt, crushed by the air pressure, suffocated by the carbon dioxide, and dissolved by acid simultaneously.  However, like on Earth, pressure and temperature decrease with altitude, so where they were, at fifty kilometers up, the temperature and pressure drop from being far too high for the toughest spacesuit, to being acceptable for an unprotected human body.  Unprotected, in the sense that you still must wear a wetsuit and breathing mask if you do not want to suffocate and get acid burns.  Still, some question why they build colonies here, as there are plenty of nice solid objects in the universe, and why they do not just leave a few researchers in blimps to study the planet and the microscopic floating alien cells, called Ouranosians.  

The reason is that since the atmosphere at the habitable level is still ten percent denser than at terrestrial sea level, cities can float without balloons.  Instead of having separate lifting gases and lifting gas balloons and gondolas with breathable atmospheres, the breathing air was the lifting gas.  Additionally, Venus is the only place in the solar system with a gravity- 8.9 meters per second squared- close enough to Earths to completely prevent low-g muscular atrophy(“Space Weakness”), and the need for ludicrously expensive centrifuge cities.  

   

[tater]

5 hours ago, HebaruSan said:

I don't think "harsh storms" is accurate for Mars. For example, when the author of The Martian spoke at Google, he admitted outright that he had to falsify that part of his book to make the plot happen:

He didn't need to do that. He could have had the landing area end up being over a lava tube, or other geologic feature that could collapse. Then have them notice the sinkhole forming, and spreading fairly quickly. Radio Mark who is in a rover away from the site (perhaps one of the two unpressurized rovers the DRA includes in addition tot he 2 pressurized ones), as he rushes back so they can take off before the MAV falls into a hole, a hole can open up, swallowing Watney. Perhaps the hole the rest of the team sees is DEEP, and when they lose him (same thing, his bio sensors can go dead), they assume that sort of fall, when really it was just a few meters. The storm was not required.

[HebaruSan]

11 minutes ago, tater said:

He didn't need to do that. He could have had the landing area end up being over a lava tube, or other geologic feature that could collapse. Then have them notice the sinkhole forming, and spreading fairly quickly. Radio Mark who is in a rover away from the site (perhaps one of the two unpressurized rovers the DRA includes in addition tot he 2 pressurized ones), as he rushes back so they can take off before the MAV falls into a hole, a hole can open up, swallowing Watney. Perhaps the hole the rest of the team sees is DEEP, and when they lose him (same thing, his bio sensors can go dead), they assume that sort of fall, when really it was just a few meters. The storm was not required.

Fine, s/had to falsify/falsified/.

[WinkAllKerb'']

sila nunam

planet star black hole etc. are system linked to each others after all

 

 

Edited October 8, 2017 by WinkAllKerb''

[mikegarrison]

8 hours ago, Bill Phil said:

It's not that far for a base at all. Even if it is, though, then that immediately rules out a colony. If it's too far for a base, it's much too far for a colony.

No, because a base is temporary and a colony is permanent. It's a mindset thing. A temporary assignment of two years (or whatever the transfer window plus transit time works out to be) is a long, long time away from home. But a permanent move there means you mentally reset "home" to be Mars.

4 hours ago, tater said:

He didn't need to do that. He could have had the landing area end up being over a lava tube, or other geologic feature that could collapse. Then have them notice the sinkhole forming, and spreading fairly quickly. Radio Mark who is in a rover away from the site (perhaps one of the two unpressurized rovers the DRA includes in addition tot he 2 pressurized ones), as he rushes back so they can take off before the MAV falls into a hole, a hole can open up, swallowing Watney. Perhaps the hole the rest of the team sees is DEEP, and when they lose him (same thing, his bio sensors can go dead), they assume that sort of fall, when really it was just a few meters. The storm was not required.

It was a literary thing. He wanted it to fit in with the "man v. nature" theme of the book, and he decided a storm was thematically the correct way to strand the guy there, even if it wasn't really the scientifically correct way to do it. It was a novel, after all.

Edited October 8, 2017 by mikegarrison

[Bill Phil]

14 minutes ago, mikegarrison said:

No, because a base is temporary and a colony is permanent. It's a mindset thing. A temporary assignment of two years (or whatever the transfer window plus transit time works out to be) is a long, long time away from home. But a permanent move there means you mentally reset "home" to be Mars.

It has nothing to do with mindset. There are plenty of people willing to do many things for money. To some, that includes staying isolated for years at a time.

If you can't support a base as far away as Mars you have no business trying to build a colony there. Remember, a colony will be, for all intents and purposes, identical to a base for at least the first ten to twenty years or so, maybe more. Sure, you may have a hundred or so "permanent residents", but you will likely have plenty of transients doing science there who will ultimately desire to return home eventually. I'm thinking something like McMurdo Station, but with longer transit times and maybe smaller.

[tater]

A collapsing lava tube would still be man vs nature, it just wouldn't be nonsense.

[YNM]

To me, both is a loss. If anything, they're hard to supply and give back. Better put orbital colonies or something.

[Shpaget]

9 hours ago, DAL59 said:

However, Venusian storms are really harsh- several hundred kilometers per hour.  However, it is constant, and a heavy airship wouldn't be pushed easily, especially if it is designed to be non-aerodynamic

 

Care to elaborate on that? A constant wind (of any strength) will quickly accelerate an untethered airship of any size to the speed of that wind. A non-aerodynamic shape will make that time shorter, not longer.

The thing with airships is that, by definition, their overall density is equal to the surrounding atmosphere. Since you want huge habitats and manufacturing systems to be suspended in air, your airships need to be huge as well. That leads to a design with large cross section that will easily catch wind.

[kerbiloid]

If warm the Venus up to thousand K, its atmosphere would dissipate much faster.
At some moment its pressure would fall down to the safe level.

So, we must focus on Venus. Focus giant mirrors.
Upd. And deliver as much water and carbon dioxide (greenhouse gases) as possible..

Edited October 8, 2017 by kerbiloid

[tater]

Venus is never going to be a normal place, even given any possible interventions you can imagine (unless you plan on getting it to spin up some how).

[kerbiloid]

Whole Venus - no. But its terminator is the only place in Solar System where humans can ever live at all, just due to normal gravity.
Should they - another question.

Upd.2. I had forgotten about redirecting potentially hazardous NEO into it, to warm it more.

Edited October 8, 2017 by kerbiloid

[tater]

Make a torus, spin it to one g. Profit (assuming you need a place for people to live that is not earth).

 

[kerbiloid]

2 minutes ago, tater said:

Make a torus, spin it to one g.

A stack of toruses is a cylinder.

[tater]

Hollow cylinders are not stable. (Longer ones)

Edited October 8, 2017 by tater

[DAL59]

7 hours ago, Shpaget said:

Care to elaborate on that? A constant wind (of any strength) will quickly accelerate an untethered airship of any size to the speed of that wind. A non-aerodynamic shape will make that time shorter, not longer.

Oops.  That is a good point.  However, there is plenty of sunlight to run propellers.   

[MatterBeam]

We do not have the techniques to sustain a floating habitat on Earth, let alone in the inclement environment on Venus. Mars is an even harsher environment, but we have the techniques to handle it.