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Is the asteroid belt easier to colonize than Mars?


SomeGuy123
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TLDR, the reasons the asteroid belt might be easier are :

1.  No stress of the aerocapture/aerobraking and the landing burn on your spacecraft.  Freed from the design constraints of that (and the need to undergo such a high stress maneuver months away from the technicians who assembled and inspected the vehicle) you could have a very different spacecraft architecture.  Since you'll never see atmosphere, you could make a bunch of rectilinear modules that can be bolted together in orbit many different ways.  Every module would have an internal aluminum honeycomb structure and would be able to tolerate the stress of connectivity in almost any direction under the very low accelerations of the maneuvering needed to reach the asteroid belt.

2.  You could deal with the radiation by finding a naturally occurring cleft in an S-type asteroid 1 km across or greater.  

3.  Colonists would live in inflated balloon style habitats, and inside the habitats would be carousel centrifuges providing the actual habitable space.  I've realized a simple open framework of aluminum struts and floor gratings (very similar to what's used in skylab) makes a ton more sense than spinning the whole habitat.  There would be 2 counter rotating carousels, each with a number of rooms and an interconnecting ring corridor all the way around.  They way you board or get off is you get into an open cage at the hub and press a button after closing the door.  Motors sync the cage to spin at the same speed as the carousel.  You open the other door and done.  

Any time you want to maintain the carousel, you stop it and work on it in shirtsleeves.  It's assembled IKEA style from a rocket load of pre-cut carousel parts and it's all bolted together by astronauts working in shirtsleeves inside the inflated habitat module.  Only minor issue I know of is that the sound of the air flowing over the carousel as it spins might get very annoying after a while.  Also, it would continually draw power as the carousel loses energy from air friction.

4.  The colonists aren't stuck at the bottom of a gravity well.  If they want to come home, they bolt together some of the modular pieces of their station/habitat and start a slow burn for earth orbit.   Engine failure is not a big deal - as long as you still have enough propellant (tank it in separate modular tanks with safety valves so a leak won't cause the contents of more than 1 tank to be lost) and at least 1 engine remaining you can probably make it home.

5.  You can test this whole system, full up, in low earth orbit.  The only difference between the colonists living in orbit and living in the asteroid belt is the microgravity of the asteroid and the diminished sunlight.  Capture an asteroid and move it into orbit, and the astronauts could try out their various mining technologies and test out living there and test their closed loop life support and everything.

6.  Much of the mining would have to be done by teleoperated (or full AI) robots.  Apparently you also need a C-type and X-type asteroid.  Hopefully you can find all 3 within a few light-seconds of each other so teleoperation is possible.  Ore hauling vehicles would take months to get between asteroids.  

7.  There's immense surface area, making mineral prospecting easy.  Just build a hopper probe and send one to each candidate asteroid.  It lands on a part of it, drills a sample and uses spectrometry, then hops to a different spot with a puff of hydrazine.  Sure, the ESA had a bit of an issue with their first try but it's doable...

Anyways, what makes Mars easier, other than the fact that it admittedly looks a lot more like a livable place in photographs?  The core of my argument is that looking at this as an engineering problem from a high level view, the asteroid belt is a far more tractable problem than Mars.  Being able to do full up testing, being freed from many causes of sudden catastrophic failure, and so on all make it far more doable.

Edited by SomeGuy123
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In the sci-fi book which I'm currently reading (Robert Ibatullin, "Rose and worm"), they did the following.

There was a kilometer-sized near-Earth asteroid, a former comet core.
With mess of silicates, water and ammonia ice inside, regolith layer on surface, visually - a piece of stone.
In the near future (2280) it should get a close (400 km) flyby of smaller asteroid.

First they dropped a descent of drillbots which made holes in the stone layer.
Then they dropped into the holes thermochemical bots which:
1) produced heat, melting/evapourating the frozen fluids, which were slowly bursting the asteroid with gas bubbles like a dough, turning it into a porous ball full of caverns.
2) produced chemical agents polymerizing the released hydrocarbons, together with ammonia, water and silicates, steeping this porous ball structures with a glue which then turned into plastic.

While all this joy was taking place, special bacteria inside caverns produced oxy, hydro and carbo.
Weaverbots made a net+cable from carbon, turning it many times around the asteroid.
When a counterpart asteroid got closer, a rocketbot took the cable and harpooned it.

So they got a 400-km (originally) asteroid dumbbell rotating once per hour with 1/5 earth gravity, with several thousand of genetically adapted human species inside living in caverns.

But they did this only after the Earth was destroyed by an alien attack.
No purpose in any colonization IRL. Just occasional mines here and ther to get rare elements for Earth industry. Mines better do on 'steroids.

Edited by kerbiloid
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You will only get paid to go to mars to do science, for the asteroids you also have mining, yes it will mostly be automatic however then the scale grows large and complex enough its will makes sense to have people on site. Still no colony more like an oil platform until things grows an magnitude or two larger yes and you start to get something like small towns. 
Yes its far ahead, you are likely to get this effect in low orbit earlier. Note it would not be self supplied even if the grow some fresh vegetables, more like an mining town. 

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1) Aerocapture: Yes it is stress, butt you can use it to save dv.....

2) same on Mars...

3) same on Mars.  Its more easy because Mars has already have an atmosphere outside. Not soo dense like earth atmosphere, but there is enough to use it as a air-recource.

4) yes, thats true, but less gravity do some negative efekts on the other hand...

5) low-earth orbit: in low earth orbit you have to re-boost the asteroids the whole time, because the (realy thin) atmosphere will break them about the years.

6) same on Mars, Mars has more recources avaiable than earth.

7) 6....

i think there are not so many differences.

since there are water on Mars, there are less problems with the colonisation.

 

 

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Mars: probably easier to get a colony to stay alive, and hit self sustaining levels much sooner (i.e. in only a few centuries).

Asteroid belt: Easier to get there and back (although I'd expect this means ion-style constant thrusting as there is no Oberth effect or aero assist during capture).  Wildly easier to hit economic payback.  The real kicker is why you would inhabit it: presumably to perform any tasks out there that robotics aren't up to (expect politics to be a huge part in determining this).  I'd expect to at least start delivering raw material from the asteroids fairly early (should be easier then landing on mars), assuming you could find a sufficiently valuable asteroid that you could nudge into Earth orbit, mold into deorbitable capsules, and then recover (finding a place that will let you bombard them from space and still legally protect your "property" may be difficult).

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1 hour ago, wumpus said:

Mars: probably easier to get a colony to stay alive, and hit self sustaining levels much sooner (i.e. in only a few centuries).

You could put an asteroid in high orbit around earth (I said LEO before but yeah it has to be in a permanent orbit above any significant atmospheric drag) and set your whole colony up.  Test the life support equipment, the mining equipment, everything.  The only difference between this colony and the one you'd really use is the sun is brighter and the asteroids are small because they had to be hauled a long way.  You empirically test your whole plan for self sustainment.  How many parts does the colony actually need from earth in practice?  How well do the colonists cope being isolated from Earth? (you'd simulate the communications time lag unless there is an emergency).  How well do things work over years?

It just seems so much more achievable to be able to practice everything a few days flight from earth than to hit Mars and it's do or die...

Why  do you think it's easier to stay alive?  What specific environment conditions are worse out in space and more likely to kill your colonists?

 

Edited by SomeGuy123
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Depends on your metrics. Is it based on total habitable surface area? Asteroid mining and O'Neill Cylinders all the way. Is it based on how easy it is to get there? Mars is easier to get to (thanks to aerobraking). Is it how difficult it is to get back? Near Earth asteroids are pretty good, and the asteroid belt is alright, but Mars is pretty bad in that regard, though.

Let's get some pros and cons:

Mars:

Pros:

Already has gravity

Surface mining is already perfected on Earth, so it'll be less of a tech leap to mine Mars' surface

Has an atmosphere

Has two asteroid moons

You can get radiation shielding from the ground itself

Cons:

Gravity well (that's a big one...)

Low surface gravity

Asteroids:

Pros:

You can pick and choose the amount of gravity

They show up in a lot of places

Travel to and from is easier

Lots of space out there

You can get much more habitable area (if mined and built into large colonies)

Cons:

Asteroid mining is by no means a perfected technology

You need a lot of material just for radiation shielding

Farther out than Mars

 

By no means is that exhaustive, so take it with a grain of salt.

The choice depends on many factors. If anything both will be colonized, but there's more accessible resources in the belt than on Mars...

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To me the question sounds a lot like "What is easier to chew? Granite or bronze?"

When we reach the point that colonizing one of them becomes feasible, the difference between colonizing asteroids or Mars becomes negligible...

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Also depends what you're planning on doing. Mars has far more resources, and more varied resources, but they will by and large be pretty similar to what you would find on earth. An individual asteroid, or even the belt itself, will have much less variety of resources, but they will be very different to what you would find on earth.

If you wanted to set up a self-sustaining colony capable of best surviving independent of the homeworld, Mars would be better. If you wanted to set up an economic base capable of doing things we can't do on earth for fun and profit, you would be better off looking at the asteroids.

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On 9/20/2016 at 0:00 PM, SomeGuy123 said:

You could put an asteroid in high orbit around earth (I said LEO before but yeah it has to be in a permanent orbit above any significant atmospheric drag) and set your whole colony up.  Test the life support equipment, the mining equipment, everything.  The only difference between this colony and the one you'd really use is the sun is brighter and the asteroids are small because they had to be hauled a long way.  You empirically test your whole plan for self sustainment.  How many parts does the colony actually need from earth in practice?  How well do the colonists cope being isolated from Earth? (you'd simulate the communications time lag unless there is an emergency).  How well do things work over years?

It just seems so much more achievable to be able to practice everything a few days flight from earth than to hit Mars and it's do or die...

Why  do you think it's easier to stay alive?  What specific environment conditions are worse out in space and more likely to kill your colonists?

 

By "staying alive" I meant without Earth assistance.  Don't count on it happening with a century or two.

Also LEO is cheating and definitely not in "the asteroid belt", although I would think that for the asteroid belt you could be sufficiently far from the Sun that radiation shielding would no longer be that critical (and you would be sufficiently deep in an asteroid for enough of your life not to care).

The asteroid belt has mining.  Mars is being sold on "a second chance in case we cause human extinction on Earth" (and presumably Alpha Proxima would be "a place that will outlive the Sun by hundreds of billion years").  No idea what the point of an LEO colony would be (we still haven't found any of those wonderful microgravity manufacturing wonders).

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1 hour ago, wumpus said:

Also LEO is cheating and definitely not in "the asteroid belt",

What I was proposing was that the advantage of the asteroid belt from a "how do we get there from here" perspective is that we could tow an asteroid to high earth orbit.  Then, we could practice living in a habitat tethered to it and practice mining.  We could do this for years and years and also simulate the actual communications lag the real colony would face.

Once the test colony has survived for a decade or so and we have fixed technical problems so that the required supply of spare parts from earth is small, then the test colony gets boosted to the asteroid belt to live there permanently.  Since there's no large accelerations required, the fragile test colony station hardware would probably be able to be reused.  

I'm not looking at long term really, just how do we organize and develop the capability to live somewhere else at all.  To me the asteroid belt seems easier because it's possible to "cheat" and simulate virtually all of the conditions the colonists would be under a few days from earth.

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Considering the mass fraction of cargo you can get to asteroid verse mars could be 4 times, yes.

How to Mine a 200-1000 m wide C-Type Asteroid.

There are no show stoppers (that we know off) in mining an asteroid, its just a matter of engineering that should be able to be done with present technology. Robotic worms would eat out the asteroid from the inside, outside a system of magnetically launched and landed buckets would move mined material up and equipment down (few m/s tops) to a mining station that orbits above the asteroid. Compressed O2 and O2 ion engines would be use for attitude control and station keeping. The mining Station would first heat the asteroid material in hydrogen gas to several thousands degrees, boiling off the lighter lowing boiling point minerals as hydride, the hydrides would be electroplated or plasmified back into raw elements (recycling the hydrogen). The heavier stuff would then be burned in fluorine and separated by boiling point and electroplating voltage (recycling the fluorine). It theory every element should be separable from each other this way, it just would be a very energy intensive process, but with continuous unfiltered sunlight as a powersupply it should be possible.

O2 would be the biggest waste product, if enough is collected it could be used to despin the asteroid, either by direct combustion with H2 or CH4 or by ion or plasma engine. Once despinned the mining station could attach to the asteroid, cover it in a tarp and devour it like a starfish eating a clam. 

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