Thoughts on spacecraft deterioration? Mothballing?

[cray]

Cosmic rays aren't EM radiation, they're very fast moving ions. The required shielding to stop cosmic rays and their secondaries is about 10 tons per square meter: a 33ft thickness of water or 100 miles of air. If they hit a superconductor, they'll only linger long enough to smash a path through the superconductor's molecules and won't care about the electromagnetic properties of a thin superconducting layer.

[HobbesHurlbut]

Wait? what readily accessible resource can we use for shielding on a spacecraft to block out Cosmic Rays?  :o

[cray]

Wait? what readily accessible resource can we use for shielding on a spacecraft to block out Cosmic Rays?  :o

Water. Rock. Plastic. Metal. Add it up to 10 tons per square meter of shielded habitat and you're golden. (Or at least as heavy as a solid gold spaceship.)

[HobbesHurlbut]

... [AAAH]
Just how big does a spaceship need to be in order to be practical?

[cray]

Just how big does a spaceship need to be in order to be practical?

For what role? The compact Gemini capsule, the "Gus Mobile," was plenty big for its missions.

[HobbesHurlbut]

For what role? The compact Gemini capsule, the "Gus Mobile," was plenty big for its missions.

I meant a space going craft, intersystem or interstellar. I meant how big does the ship have to be to have sufficient cosmic ray shielding and still have room for the rest of the components it need to be a spaceship?

[cray]

I meant a space going craft, intersystem or interstellar. I meant how big does the ship have to be to have sufficient cosmic ray shielding and still have room for the rest of the components it need to be a spaceship?

If you use something like iron for the hull the required hull thickness will only be about 1.3 meters. Tungsten would take it to about 53cm. BT ships, as always, have plenty of volume to spare.

Do note that cosmic rays are not a short term threat. You need a year or more of unmitigated exposure to start really racking up the rads from them. They're not like a solar flare or radiation belt.

[HobbesHurlbut]

If you use something like iron for the hull the required hull thickness will only be about 1.3 meters. Tungsten would take it to about 53cm. BT ships, as always, have plenty of volume to spare.

Do note that cosmic rays are not a short term threat. You need a year or more of unmitigated exposure to start really racking up the rads from them. They're not like a solar flare or radiation belt.

Is Tungsten or Lead better than the other at rad shielding?

[Daryk]

Lead is best for gamma shielding.  Cray is talking about using tungsten to shield against cosmic rays:

Cosmic rays aren't EM radiation, they're very fast moving ions. The required shielding to stop cosmic rays and their secondaries is about 10 tons per square meter: a 33ft thickness of water or 100 miles of air. If they hit a superconductor, they'll only linger long enough to smash a path through the superconductor's molecules and won't care about the electromagnetic properties of a thin superconducting layer.

[cray]

Is Tungsten or Lead better than the other at rad shielding?

Lead is slightly better because of its higher atomic number, though it is only about half as dense as tungsten and far, far softer. If you want a multi-purpose hull material, look into tungsten-based materials and accept the slight percentage gain in thickness required to stop radiation.

[AnubisZombie]

Solid gold spaceships  [rockon] Now that's bling. Where can you get one?