Ok, so let's say humans go out into space; first we went to the moon, because it was closest.  we'd probably go to mars next for the same reason, then maybe continue along those lines. But for long term exploitation and permanent bases, where will it make sense to us to start up permanent places?
And this will presumably change over time, I suppose, where places very important early on might fade in significance later on.

So what would the timeline/breakdown look like, IYO?

RPGPundit

The Millennial Project: Colonizing the Galaxy in Eight Easy Steps, by Marshall T. Savage, with an introduction by Sir Arthur C. Clarke in the second edition, is one detailed consideration of the question.

Wikipedia entry

Space Power Satellites, and Fuel Depots in earth orbit.

Put a station and fuel depot at the L1 point in the earth moon system. Exploit the lunar poles for water and manufacture propellant and oxygen to ship to the L2 point.

The exploration of  Mars followed by cyclers establishing a regular Earth-Mars route. Then the terraforming of Mars into earth like conditions. The Moon would be searched for He3 desposits to be shipped back to earth for exploration.

Continued expansion of fuel depots and space based manufacturing to supply expeditions to Saturn to start skimming He3 for fusion reactors. Exploration of Titan for unique resources available for exploitation. Note Saturn has several order of magnitude less issues with radiation than Jupiter which is why we would go there for He3 skimming.

Scattered among this would be various anarctica style science stations and various tourist stations. Meanwhile on earth experiments and pllaning are pursued for the construction of a beanstalk. A elevator into space.  Expeditions to various near earth asteroids would be undertaken not only for science to find a suitable tether point for the beanstalk to be moved into Earth orbit (past geosynchronous orbit).

After the beanstalk is estabilshed there is an explosion of humanity into space as the cost to get into space drops by an order of magnitude Every groups with a half-baked idea and the means for living in the black will be making their way up the beanstalk to a ship.

The key to making this happen is a high enough launch rate to drive down the cost of access space. But chemical rockets go only so far and only a breakthrough, like a beanstalk, will be radical enough to allow space access on the level of taking a trip across the ocean.

The the near term scenario is get access to space for humans as useful and easy as access to Antarctica.  Which is largely a mix of science and tourism.

If I had a spacefaring megacorp at my disposal, I'd let everyone else focus on Mars and the Belt, and I'd be heading towards Venus.

I have no idea what resources it would have over other targets, but I've read that there's a point in Venus' atmosphere where the density below is about that of water, and the temperature is tolerable to humans. This means that you could float stations on a sea of gasses that could eventually cover the whole planet. Humans could walk around outside on these stations with nothing more than oxygen masks, and no risk of boiling their blood, etc.

If the purpose of colonization was to spread out human population ,it seems like a decent enough place. The Hellscape is miles below and falling would be a risk, but it would be a lot easier to keep a colony going than it might be in a place where pressurization and lack of atmospheric radiation shielding was an issue.

Colonies in Space by TA Heppenheimer.
Entering Space by Robert Zubrin.

Those will both get you started.

Just to play "debbie-downer" here...

...can mankind (in it's current form) survive in deep space?  Our trips to the moon still had the benefit of staying somewhat within the earth's magnetic field.  A long trip to Mars means an incredible exposure to solar radiation.  It could be toxic to even try to go.

Quote from: Monster Manuel;446439I have no idea what resources it would have over other targets, but I've read that there's a point in Venus' atmosphere where the density below is about that of water, and the temperature is tolerable to humans. This means that you could float stations on a sea of gasses that could eventually cover the whole planet. Humans could walk around outside on these stations with nothing more than oxygen masks, and no risk of boiling their blood, etc.

Eclipse Phase has Venus colonized exactly like this -- aerostats high up in the Venusian atmosphere.

There are also plenty of mining operations on the planet's surface, operated remotely using special heat-resistant drones.

Quote from: gonster;446482Just to play "debbie-downer" here...

...can mankind (in it's current form) survive in deep space?  Our trips to the moon still had the benefit of staying somewhat within the earth's magnetic field.  A long trip to Mars means an incredible exposure to solar radiation.  It could be toxic to even try to go.

The solution is using water as shielding. You need the water anyway, so it's not an added weight.

-clash

Quote from: The Butcher;446537Eclipse Phase has Venus colonized exactly like this -- aerostats high up in the Venusian atmosphere.

There are also plenty of mining operations on the planet's surface, operated remotely using special heat-resistant drones.

In Larry Niven's ancient story (early 60s) about the first ship to Venus - in one of the Known Space story collections - the atmospheric ship is actually a kind of balloon.

-clash

Ain't there lovely sulphuric acid clouds hangin' in Venus' atmosphere? Sorry for peeing in your corn flakes guys.

Quote from: gonster;446482Just to play "debbie-downer" here...

...can mankind (in it's current form) survive in deep space?  Our trips to the moon still had the benefit of staying somewhat within the earth's magnetic field.  A long trip to Mars means an incredible exposure to solar radiation.  It could be toxic to even try to go.

Not the point of the OP though... Realistically you would do all your exploration with remote drones, build pre-fab'ed habitats etc etc There is no benefit in going there in person unless you have already discovered something worthwhile to investigate.

I can't for example see exploration of Venus being very worthy when there is a possibility of life on Europa due to liquid oceans. So if you want to get the biggest bang for your buck you send out drones and robots then analyse the data then target exploration toward highest % of life.

Then in the far far future is you need to you might look to colonisation for raw minerals but Earth has got to be pretty fucked up for it to be profitable to send a ship to the asteroid belt to collect nickle and iron rather than just recycling what we already have on earth.

The idea of colonisation for actual living is a tricky one which we have discussed before. Again for it to be viable to send large numbers of people to distant worlds that are entirely inhospitable to human life rather than say colonise the Antarctic or under the sea or the Gobi desert, the earth has to be pretty seriously fucked up but yet still capable of mounting said expedition.

Now if you can use your drones to test interstellar flight and identify a habitable world within reach then that is a game changer. Or if for example a drone on Europa identified a water ocean and some sort of life then a human mission would be a certainly and I could see a Science station set up with possible tourism, which you would base on tests on a deep sea trench in the Antarctic someplace.

Quote from: flyingmice;446549The solution is using water as shielding. You need the water anyway, so it's not an added weight.

Long ago I came up with the idea of a ship that had external water tanks all around it for reaction mass and shielding - essentially the crew sat in the middle of a flying ice cube.

Quote from: boulet;446552Ain't there lovely sulphuric acid clouds hangin' in Venus' atmosphere? Sorry for peeing in your corn flakes guys.

Venus' atmosphere is stratified, and the composition differs at varying altitudes. The area at around 50 km above the surface is where temperature and pressure are very close to Earth levels. That said, though you would be above the sulphuric acid haze layer, you would be in the area of sulphuric acid clouds. The materials the aerostats would be constructed of would have to be ceramics and other acid-resistant materials, and you couldn't just walk around with a breathing mask on in your skivvies. Still, it would be far easier to colonize this area than colonizing any other non-earth real estate in the solar system.

-clash

Quote from: flyingmice;446560Still, it would be far easier to colonize this area than colonizing any other non-earth real estate in the solar system.

I think terraforming Mars would be easier provided it had enough volatiles on the planet or that sending down comets and/or ice asteriod can be made to work without leaving the planet choked in dust for a 1,000 years.

Mars has a near earth day length (25 hours) and any thick atmosphere created will last far long then the length of any known human civilization.

Quote from: estar;446563Mars has a near earth day length (25 hours) and any thick atmosphere created will last far long then the length of any known human civilization.

I thought I read that Mars' mass was a little too low to retain durably an atmosphere. You're saying that it would be a slow phenomenon that doesn't make terraformation useless?