Space is, and I must emphasize this in the strongest possible terms, really FUCKING BIG and dangerous GRBs tend to be tightly focused given the inverse square law.

It's highly unlikely that a ship gets hit by a GRB.

On the other hand, general radiation gets worse the faster you go, so you need shielding either way. All you have to do is line the walls of your ship with a shit ton of water, which can be mined in space.

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arbuge an hour ago | parent | next [-]

> All you have to do is line the walls of your ship with a shit ton of water, which can be mined in space.

But that water needs to be encased in something, and your problem now becomes protecting the encasement.

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zdragnar 4 hours ago | parent | prev | next [-]

I'm reminded of the joke that the most dangerous thing in the ocean is all the water.

We don't have fuel sources that can run long enough for the trip, and deep space won't have enough solar radiation. We would need reliable mining spots along the way to replace metals made brittle by exposure or punctured by micro asteroids.

Even travelling at 1% the speed of light, stray hydrogen atoms become a problem. Not counting acceleration or deceleration time, that would be over 400 years just to get to the nearest star, let alone one with a habitable planet.

	▲	m4rtink 3 hours ago \| parent [-]
		In all current realistic plans the idea is to accelerate once and decelerate (if needed) at the destination. So not really doable to stop by on the way, unless you are going really slow - or its a part of the Voyage (e.g. multi millennia round trip where you replenish in every suitable star system along the way) provided your ship can handle the acceleration (could be assisted by built infra) and deceleration of a given "hop".

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cdelsolar 4 hours ago | parent | prev [-]

Can you really mine water in interstellar space, how? there’s not that many asteroids just floating out there, I think.

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GolfPopper 4 hours ago | parent [-]

Maybe the previous poster was referring to the Kuiper Belt and/or the Oort Cloud? There's certainly plenty of water ice out there, with no particularly deep gravity wells to worry about.

Collecting it while usefully en route to another star system seems like it would be tricky from a delta-v perspective, but maybe the solution is to:

1) build a small worldship from an appropriate asteroid 2) fill your internal ocean in the outer solar system over the course of a generation or three 3) dive back down the gravity well for a gravitational assist from the Sun as you head to your interstellar destination 4) en route, slowly use part of your ocean as propellant, while living inside the rest of it as shielding

	▲	m4rtink 3 hours ago \| parent [-]
		There is a nice concept I've read I think on either Orions Arm or Project RHO about basically settling the Kuiper Belt and the Oort Cloud. It would not really be about primarily traveling anywhere, just people settling this are with its immense resources over many generations, until possibly the ones on the furthest reaches would be able to make the jump to the next systems Oort cloud & slowly settling it down the gravity well, maybe even reaching the inner system eventually, provided something so tiny and sweltering would be of interest for them by that point. ;-) IMHO this is actually much closer to how humans spread along the Earths surface. It was no like someone just get up and walked from Afrika to Australia. The various human group just expanded their habitat over time until they spread all over the place over many thousands of years and this would be similar.