17 thoughts on “Making Space Ships”

1. I like the nod to Clarke (RAMA.)

   This is a great idea.

2. I’m not fussy, I don’t care what they make spaceships out of as long as they’re made.

   1. Of course, when I say great idea, the sticky part is in the implementation. Ionized dust would seem a good reactant (that’s not the right word, but I’m drawing a blank… reaction mass?) and I’d integrate the thing before sending it out. We may have the tech to create onsite but that adds two many failure modes IMHO.

      1. “Reaction mass” or “propellant” is the correct term.

         You have me wondering, what kind of performance can we get from an ion dust engine? What kind of charge/mass ratio can we get on dust? Positive or negative charge? What kind of weapon grade effect would this engine present to tailgaters?

         1. I know I’ve read about them somewhere, but for the life of me can’t seem to find a google link. Probably found it in some golden era pulp fiction in my youth! It would probably perform like a hall thruster and perhaps heated to a liquid rather than pure dust?

3. That’s no asteroid!

   1. OK, how about an old man comes to your jail cell and croaks “the world is hollow and I have touched the sky” before his computer activated Obedience Device kicks in?

      The point being that there is ample precedent in pop-cul sci-fi of asteroid-sized space ships or asteroid space ships.

      1. Have you been to Epcot?

4. If an asteroidal spaceship re-enters the atmosphere does it become a meteoroidal spaceship?

   Asking the important questions.

   1. Only if it left it in the first place! Bada bing!

5. I’m not so sure it’s a great idea to take asteroid materials and catapult them as a means of propulsion. Every little impulse will be a new space rock hurtling around the sun. A moderate sized asteroid has a mass of tens of millions of times more than what we have launched into LEO, and look at what a mess space junk has made here around earth. Yes, space is big, but disassembling asteroids as a means of low ISP propulsion seems a poor/wasteful use of materials, and a potential danger.

   1. This i why I said ionized dust. It will burn up in any atmosphere and probably not harm most other structures. Considering the quantity of stuff already out there this would be like peeing into the ocean.

      1. Would there be the equivalent of shipping lanes though?

   2. Quite. This idea looks like the 3-D printer equivalent of that old saw about all problems looking like nails if the only tool you have is a hammer. This is attempting to make mountains come to Mohammed. It’s inefficient and dumb.

      One or more processing ships should converge on a given asteroid, munch it up and extract is various useful materials, including volatiles – for which tankage can be fabricated, in situ, from metals or polymer composites. Then the various tanks and ingots should be gotten on their ways to useful points of application via in-situ-fabricated solar arrays and small ion thrusters brought along for the purpose along with Mars-sourced argon as reaction mass.

      Asteroids processed in this way would, in all likelihood simply be consumed completely by the processing machinery as I can’t really think of any chemical constituent of an asteroid that wouldn’t be useful in space. No-tailings mining.

      1. I think the assumption is the entire rock would be useful, not just certain volatiles.

6. What kind of delta V / orbital mechanic challenges does this create?

   1. The delta V wouldn’t really matter much. It isn’t going to be high thrust. Eventually you use up the entire rock.

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