The Case For Space Colonization

[Jokodo]

Supposedly the Oort cloud extends approximately 2 light years out from the sun. Assuming that Proxima Centauri has a similar-sized Oort cloud, then humans can "island hop" from one object to another, from one star to the next, each hop taking place within a relatively short time span.

This is obviously no Battlestar Galactica-style of space travel, but it's much safer.

Not really.

Most of the objects in the Oort cloud are believed to be comet-like objects, not asteroids. That means they're mostly just ice lumps.

Most of them are also very small - so you don't have any appreciable gravity there. And most of them, you could reach escape velocity with a bicycle and a ramp if it weren't for the fact that due to the lack of gravity (and the icy surface) you don't get much traction with your tires.

And that's only one of the reasons why you wouldn't build a colony there - they're just in interstellar space. The sun, this far out, is no brighter than some of the brightest night stars we have, so good luck growing food with photosynthesis.

And they're also very sparse. You'd have to be lucky to find one on your way. You might think you could at least use them to resupply on water and/or deuterium for your fusion drive, but when you're already traveling at a reasonable velocity, changing course, decelerating to intercept the body, and accelerating again afterwards is going to be a significant net-cost.

 

[Loren Pechtel]

Most of them are also very small - so you don't have any appreciable gravity there. And most of them, you could reach escape velocity with a bicycle and a ramp if it weren't for the fact that due to the lack of gravity (and the icy surface) you don't get much traction with your tires.

Objection: Escape velocity is a scalar, not a vector. Your bicycle is enough, no ramp needed.

I would think you actually could do it if you didn't have a pesky space suit restricting you. You need a depression (say, impact crater) that's smooth enough to bike across. That will provide some downward force.

Without something of the sort no wheeled vehicle can possibly exceed orbital velocity--at that point your weight is zero so your friction is zero.

 

[Jokodo]

Mir was continuously occupied for 3,644 days without a single fatality or serious problem with life support. Valeri Polyakov spent 437 consecutive days onboard in 1994/5; he is still alive and working as the Deputy Director of the Ministry of Public Health in Moscow at the age of 75. He is in better health than most 75 year old men.

The ISS has been continuously occupied for 17 years, 3 months and 13 days at the time of this post, and there is no current plan or expectation that this will end any time soon; Roscosmos and NASA have committed to operate the station at least until 2024.

If you can safely operate a crewed space station for a quarter of a century, it doesn't seem implausible that you could do so indefinitely. Particularly as each new station design builds on the lessons from the previous one, and can take advantage of advances in materials and technologies.

A modern car is expected to be both better designed and more reliable than one built eighteen years ago.

But neither Mir nor the ISS are/were fully autonomous.

The requirement on their backup systems was solely to keep the crew alive for as long as it takes to schedule and implement an emergency supply from earth. The requirement on a backup system on a fully autonomous station would be to keep the crew alive for as long as it may take them to repair the main system with the materials and tools available on the station, which may be considerably longer.

Sure. But we are talking about stuff no further away than Mars. Not a situation where there can never be another resupply or repair mission.

People seem to be talking about different things. Though the wait for a resupply mission can be a very long wait even when you're in the Mars range. Even there, it would make things easier if we just made the possibility to repair any vital component in situ a top priority in the design of the systems.

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Most of them are also very small - so you don't have any appreciable gravity there. And most of them, you could reach escape velocity with a bicycle and a ramp if it weren't for the fact that due to the lack of gravity (and the icy surface) you don't get much traction with your tires.

Objection: Escape velocity is a scalar, not a vector. Your bicycle is enough, no ramp needed.

I would think you actually could do it if you didn't have a pesky space suit restricting you. You need a depression (say, impact crater) that's smooth enough to bike across. That will provide some downward force.

Without something of the sort no wheeled vehicle can possibly exceed orbital velocity--at that point your weight is zero so your friction is zero.

Assuming a spherical object...

You can still reflect off some bump in what seemed to be an orbital trajectory.

 

[bilby]

Most of them are also very small - so you don't have any appreciable gravity there. And most of them, you could reach escape velocity with a bicycle and a ramp if it weren't for the fact that due to the lack of gravity (and the icy surface) you don't get much traction with your tires.

Objection: Escape velocity is a scalar, not a vector. Your bicycle is enough, no ramp needed.

Except:

I would think you actually could do it if you didn't have a pesky space suit restricting you. You need a depression (say, impact crater)

...or a ramp...

that's smooth enough to bike across. That will provide some downward force.

Without something of the sort no wheeled vehicle can possibly exceed orbital velocity--at that point your weight is zero so your friction is zero.

Unless the surface you are riding on 'ramps up' away from the horizontal gravitational plane.

So in other words, you just refuted your own objection.

If there's anything to object about in the scenario, it's the idea that ice in the Oort Cloud would be slippery. The low coefficient of friction on icy surfaces on Earth is due to a layer of meltwater that forms when the surface is under load (ice is less dense than liquid water, so tends to melt under pressure). That phenomenon occurs at relatively high temperatures; at the kinds of temperatures found in the Oort Cloud, ice is about as slippery as dry concrete.

 

[Jokodo]

Except:

I would think you actually could do it if you didn't have a pesky space suit restricting you. You need a depression (say, impact crater)

...or a ramp...

that's smooth enough to bike across. That will provide some downward force.

Without something of the sort no wheeled vehicle can possibly exceed orbital velocity--at that point your weight is zero so your friction is zero.

Unless the surface you are riding on 'ramps up' away from the horizontal gravitational plane.

So in other words, you just refuted your own objection.

If there's anything to object about in the scenario, it's the idea that ice in the Oort Cloud would be slippery. The low coefficient of friction on icy surfaces on Earth is due to a layer of meltwater that forms when the surface is under load (ice is less dense than liquid water, so tends to melt under pressure). That phenomenon occurs at relatively high temperatures; at the kinds of temperatures found in the Oort Cloud, ice is about as slippery as dry concrete.

I was thinking about ice maybe not being slippery at those temperatures, but I left it in nonetheless.

 

[Wiploc]

I'm thinking Velcro wheels and a Velcro ramp. With a little thought, we could do better than that. It's obvious that the lack of weight can be dealt with.

 

[Loren Pechtel]

I'm thinking Velcro wheels and a Velcro ramp. With a little thought, we could do better than that. It's obvious that the lack of weight can be dealt with.

Magnets would work far better--it wouldn't sap your energy as you pull away.

 

[barbos]

Supposedly the Oort cloud extends approximately 2 light years out from the sun. Assuming that Proxima Centauri has a similar-sized Oort cloud, then humans can "island hop" from one object to another, from one star to the next, each hop taking place within a relatively short time span.

This is obviously no Battlestar Galactica-style of space travel, but it's much safer.

Oort cloud is only marginally more dense than empty space
I suggest finding a star with very earth like planet, preferably with primitive life already there and then sending bunch of people in suspended animation. Within 100 light years there are 15000 stars. Chances are good that there is another Earth in there.

 

[Jimmy Higgins]

Except:

I would think you actually could do it if you didn't have a pesky space suit restricting you. You need a depression (say, impact crater)

...or a ramp...

that's smooth enough to bike across. That will provide some downward force.

Without something of the sort no wheeled vehicle can possibly exceed orbital velocity--at that point your weight is zero so your friction is zero.

Unless the surface you are riding on 'ramps up' away from the horizontal gravitational plane.

So in other words, you just refuted your own objection.

If there's anything to object about in the scenario, it's the idea that ice in the Oort Cloud would be slippery. The low coefficient of friction on icy surfaces on Earth is due to a layer of meltwater that forms when the surface is under load (ice is less dense than liquid water, so tends to melt under pressure). That phenomenon occurs at relatively high temperatures; at the kinds of temperatures found in the Oort Cloud, ice is about as slippery as dry concrete.

A puck provides very little pressure at all, but I can slide it a good distance on a frozen pond. Ping pong ball would likely be stopped by air resistance before friction stopped.

 

[bilby]

Except:

...or a ramp...
Unless the surface you are riding on 'ramps up' away from the horizontal gravitational plane.

So in other words, you just refuted your own objection.

If there's anything to object about in the scenario, it's the idea that ice in the Oort Cloud would be slippery. The low coefficient of friction on icy surfaces on Earth is due to a layer of meltwater that forms when the surface is under load (ice is less dense than liquid water, so tends to melt under pressure). That phenomenon occurs at relatively high temperatures; at the kinds of temperatures found in the Oort Cloud, ice is about as slippery as dry concrete.

A puck provides very little pressure at all, but I can slide it a good distance on a frozen pond. Ping pong ball would likely be stopped by air resistance before friction stopped.

Sure. At temperatures within a dozen or so K of freezing, the pressure needed is fairly low.

The temps in the Oort Cloud are more than 250K below freezing. At such temperatures, the coefficient of friction is very similar to that of concrete. Its not slippery in the way that ice is on the Earth's surface.

Your frozen pond also started out very flat and smooth (because it was liquid, and under the influence of the Earth's gravity), and hasn't had long for the surface to become roughened by impacts, or by various forces acting to disrupt it.

Most Oort Cloud comet like bodies have low gravity and haven't been liquid for thousands of millions of years.

And a hockey puck would go a fairly long way on a smooth concrete surface.

Everyday human experience is a poor guide to the physics of extreme conditions.

 

[Jimmy Higgins]

Except:

...or a ramp...
Unless the surface you are riding on 'ramps up' away from the horizontal gravitational plane.

So in other words, you just refuted your own objection.

If there's anything to object about in the scenario, it's the idea that ice in the Oort Cloud would be slippery. The low coefficient of friction on icy surfaces on Earth is due to a layer of meltwater that forms when the surface is under load (ice is less dense than liquid water, so tends to melt under pressure). That phenomenon occurs at relatively high temperatures; at the kinds of temperatures found in the Oort Cloud, ice is about as slippery as dry concrete.

A puck provides very little pressure at all, but I can slide it a good distance on a frozen pond. Ping pong ball would likely be stopped by air resistance before friction stopped.

Sure. At temperatures within a dozen or so K of freezing, the pressure needed is fairly low.

I'd say, as a puck provides about 0.17 psi worth of pressure.

The temps in the Oort Cloud are more than 250K below freezing.

And cooler by the lake!

At such temperatures, the coefficient of friction is very similar to that of concrete. Its not slippery in the way that ice is on the Earth's surface.

Well, I haven't been to the Oort Cloud, so I'll need to take your word for it

Your frozen pond also started out very flat and smooth (because it was liquid, and under the influence of the Earth's gravity), and hasn't had long for the surface to become roughened by impacts, or by various forces acting to disrupt it.

Most Oort Cloud comet like bodies have low gravity and haven't been liquid for thousands of millions of years.

And a hockey puck would go a fairly long way on a smooth concrete surface.

Everyday human experience is a poor guide to the physics of extreme conditions.

Yeah, but you haven't supported your claim that ice ~ concrete frictionally at terribly low temps.

 

[bilby]

Sure. At temperatures within a dozen or so K of freezing, the pressure needed is fairly low.

I'd say, as a puck provides about 0.17 psi worth of pressure.

The temps in the Oort Cloud are more than 250K below freezing.

And cooler by the lake!

At such temperatures, the coefficient of friction is very similar to that of concrete. Its not slippery in the way that ice is on the Earth's surface.

Well, I haven't been to the Oort Cloud, so I'll need to take your word for it

Your frozen pond also started out very flat and smooth (because it was liquid, and under the influence of the Earth's gravity), and hasn't had long for the surface to become roughened by impacts, or by various forces acting to disrupt it.

Most Oort Cloud comet like bodies have low gravity and haven't been liquid for thousands of millions of years.

And a hockey puck would go a fairly long way on a smooth concrete surface.

Everyday human experience is a poor guide to the physics of extreme conditions.

Yeah, but you haven't supported your claim that ice ~ concrete frictionally at terribly low temps.

https://www.sciencedirect.com/science/article/pii/S1359645403000612

 

[Jimmy Higgins]

https://www.sciencedirect.com/science/article/pii/S1359645403000612

Fake news!

The Exec Summary indicates that frictionality to temperature is a linear relationship... it doesn't indicate how much so.

 

[Loren Pechtel]

Except:

...or a ramp...
Unless the surface you are riding on 'ramps up' away from the horizontal gravitational plane.

So in other words, you just refuted your own objection.

If there's anything to object about in the scenario, it's the idea that ice in the Oort Cloud would be slippery. The low coefficient of friction on icy surfaces on Earth is due to a layer of meltwater that forms when the surface is under load (ice is less dense than liquid water, so tends to melt under pressure). That phenomenon occurs at relatively high temperatures; at the kinds of temperatures found in the Oort Cloud, ice is about as slippery as dry concrete.

A puck provides very little pressure at all, but I can slide it a good distance on a frozen pond. Ping pong ball would likely be stopped by air resistance before friction stopped.

The frozen lake isn't all that cold.

An observation from -30F well-compacted snow: The terrain was quite steep but we had no problem walking up it in boots. The sun rose and walking quickly became impossible--the old joke about taking one step forward and sliding two back was reality. (Standing on two feet was possible, standing on one meant you slipped.)

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https://www.sciencedirect.com/science/article/pii/S1359645403000612

Fake news!

The Exec Summary indicates that frictionality to temperature is a linear relationship... it doesn't indicate how much so.

You mean it should be filed under "friction"?

 

[Jimmy Higgins]

The frozen lake isn't all that cold.

An observation from -30F well-compacted snow: The terrain was quite steep but we had no problem walking up it in boots. The sun rose and walking quickly became impossible--the old joke about taking one step forward and sliding two back was reality. (Standing on two feet was possible, standing on one meant you slipped.)

- - - Updated - - -

https://www.sciencedirect.com/science/article/pii/S1359645403000612

Fake news!

The Exec Summary indicates that frictionality to temperature is a linear relationship... it doesn't indicate how much so.

You mean it should be filed under "friction"?

You do realize that snow is not ice, right? Kind of like comparing a beach of sand with glass.

 

[bilby]

The frozen lake isn't all that cold.

An observation from -30F well-compacted snow: The terrain was quite steep but we had no problem walking up it in boots. The sun rose and walking quickly became impossible--the old joke about taking one step forward and sliding two back was reality. (Standing on two feet was possible, standing on one meant you slipped.)

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You mean it should be filed under "friction"?

You do realize that snow is not ice, right? Kind of like comparing a beach of sand with glass.

You do realize that Oort Cloud objects are not solid homogeneous lumps of ice, right? They are frequently popularly described as 'dirty snowballs'; Those that enter the inner solar system as comets tend to have a surface that is black as soot, due to the driving off of volatile compounds (including water) on approach to the sun, leaving behind a dusting of non-volatile material. In addition to water ice, they typically contain methane, ethane, carbon monoxide, hydrogen cyanide, and likely some ammonia, all in solid form at the temperatures of the outer solar system.

 

[Loren Pechtel]

The frozen lake isn't all that cold.

An observation from -30F well-compacted snow: The terrain was quite steep but we had no problem walking up it in boots. The sun rose and walking quickly became impossible--the old joke about taking one step forward and sliding two back was reality. (Standing on two feet was possible, standing on one meant you slipped.)

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You mean it should be filed under "friction"?

You do realize that snow is not ice, right? Kind of like comparing a beach of sand with glass.

Same effect, though.

 

[LordKiran]

Would any of you want to leave Earth for Mars or a Babylon 5 kind of colony? Once you are there you can't just hop on a spceship to leave.
The Hubble repairs were pretty simple, but were a very difficult task in zero g. Expand that to a large complex structure in space.

For Earthbound benchmarks, how long does it take to design, build, and fully debug an aircraft carrier or nuclear sub? I just don't see how a Babylon 5 habitat could be built.

If you are not happy with life on Earth, why would you be happy on Mars or the moon?

The only reason to leave LEO is asteroid interception. We know it is when not if.

Same reason why people want to climb Everest, or go to Antarctica.

I would do it in a heartbeat, just for the experience of the thing.

You appear to have less than the average level of curiosity; That's not a bad thing at all, but most people are more curious than you, which is why we are not still sitting around in Olduvai Gorge staring at rocks but not bothering to bang them together.

View attachment 14485

Climbing mountains takes maybe a few months out of your life if it doesn't kill you. Colonizing another planet is quite a permanent shift and not something most people will be able to tolerate, especially when you're confined indoors...forever

Terraforming mars is a pipe dream.

One: mars has no magnetic sphere so any atmosphere you create would be blown away by solar winds.

Two: Mars has approx. 40% of earth's gravity which incurs all the normal problems living in a low grav environment for extended periods does.

Three: because of issue two, there's no guarantee that you could have viable births on the planet which is an automatic dealbreaker in itself for permanent settlements.

Four: the amount of energy and time needed to perform this task would almost certainly get you better returns invested here on earth until we can prove that a permanent settlement on mars could be economically sustainable.

Five: even if we could create economically sustainable settlements on the red planet there's no reason to populate it with many people. Just a few to keep the machines running who regularly switch shifts months at a time.


On the whole I don't understand the desire to send people to mars at all. Super advanced automatons capable of speculating, mining, refining and then shipping the goods they find should be sufficient with nothing more than a skeleton crew in space to oversee planetside operations. It's a sad fact of reality that your imagination is vastly more interesting and stimulating than anything you'd actually find in space (That wouldn't instantly kill you)

So instead of all this mars talk why not consider things happening right now that could change the landscape here at home like asteroid mining?

 

[Loren Pechtel]

On the whole I don't understand the desire to send people to mars at all. Super advanced automatons capable of speculating, mining, refining and then shipping the goods they find should be sufficient with nothing more than a skeleton crew in space to oversee planetside operations. It's a sad fact of reality that your imagination is vastly more interesting and stimulating than anything you'd actually find in space (That wouldn't instantly kill you)

So instead of all this mars talk why not consider things happening right now that could change the landscape here at home like asteroid mining?

If it reaches the point that super-advanced automation can do all that--including the upkeep--then we will have reached the point that the only jobs will be creative tasks. We are nowhere near that.

And note that if we can do that it will be perfectly possible to live safely on Mars. Some people will choose to.