[Scourge of Ages]

Bah, you're going about it all wrong. You don't piece together space junk to build ships, you just need an orbital foundry to reduce all the junk to component metals and then builds new stuff.
Alternate: wrap all the space junk into a giant ball, decelerate it and drop it back to Earth (preferably into a desert or something) then you can reclaim it!

[SpardaSon21]

Molten alloys in zero gee.  Wonderful.

[watsisname]

Well, not necessarily.  Just smelt them on a rotating refinery. 

[NGTM-1R]

Molten alloys in zero gee.  Wonderful.

Casting in zero-gee should actually produce a stronger material.

[redsniper]

How so?

[NGTM-1R]

Structure. Material is more evenly spaced throughout the cast item, resulting in fewer flaws or weaknesses.

[SpardaSon21]

Well, if we want endo steel for our BattleMechs so we can fight off the impending Clan invasion Steven Colbert has warned us about, I suppose we do need orbital foundries.  Oh, and some of those Clan double heatsinks rscaper found on Google.

[Kosh]

Structure. Material is more evenly spaced throughout the cast item, resulting in fewer flaws or weaknesses.

Indeed, because the moon and space has little and no gravity respectively that creates a unique research and manufacturing environment for biotech and materials sciences.

[watsisname]

Indeed, because the moon and space has little and no gravity respectively that creates a unique research and manufacturing environment for biotech and materials sciences.

You fail physics forever. 

[Nuke]

i've kludged on a fusion reactor, but i think spacecraft is where i'm going to have to draw the line.

lies

[Herra Tohtori]

Even better...

[Kosh]

Indeed, because the moon and space has little and no gravity respectively that creates a unique research and manufacturing environment for biotech and materials sciences.

You fail physics forever. 

The Earth's gravity is 1g, the moon's is 1/6g, space is 0g. How is that a fail?

[Herra Tohtori]

Saying there's no gravity in space is, although a commonly accepted colloquialism, technically incorrect.

Zero g refers to zero gravitational acceleration, a situation that occurs when everything experiences locally identical acceleration due to gravity field; this happens in free fall situation such as parabolic trajectory or space flight when no acceleration is produced by ship's thrusters. It's also known as microgravity.

Gravity itself (thankfully) exists in space just as it does on planet surface - it's the reference frame that makes us either notice the gravitation or not.

[Flipside]

I suppose the best way to imagine it is still the famous 'rubber sheet', even when the sheet is not 'stretched' near a large mass, it still exists?

Edit: I suppose that does show the difference between 'Zero G' which is simply everything at the same ROA and 'No Gravity', which is something else.

[Nuke]

Even better...

 

[Kosh]

Saying there's no gravity in space is, although a commonly accepted colloquialism, technically incorrect.

It was intended as a colloquialism. My point is still valid.

[iamzack]

gravity is just a theory

[Bobboau]

so are magnets.

[Herra Tohtori]

All we're saying is that you should teach the controversy.