MagnaCool--Habitable Exoplanet!

[Ned]

Originally posted by Kuciwalker
Well not quite. Either way you trace out the same amount of space, ignoring galactic rotation and stuff like that. But at higher speeds impacts are far more dangerous.

At any reasonable speed for interstellar travel it will be a problem. As in, nuclear bombs exploding on the bow.

Columbus sailed with 3 ships. Having three ships made it at least three times more likely that at least one of them would survive the voyage. I don't understand why there is so much resistance to this here.

I am no expert on probability calculations, so please forgive me.

But let's assume that the probability of ecountering a deadly mass enroute is proportional both to the cross section of the ship and to its speed. If you had 3 ships instead of one, assuming the same size ships, you should be able to go 3 times as fast and assure that at least one of them arrives safely.

Not so?

In other words, interstellar travel seems to require fleets of ships to make it practical.

[Dauphin]

The energy released in an impact (assuming non-relativistic speeds) is proportional to the square of the speed. The count of particles that fall into the 'kill' zone as you increase speed is dependent on the distribution of sizes of particles in the interstella medium. I would not assume proportionality.

If you increase the number of independent launches you increase the chance of a succesful mission.

If you have a 1/3 chance of success on any given mission you will have a ~70% chance of at least one success with 3 ships.

[Jon Miller]

What would b ebest is to have a modular spread out ship... the ships already have to be huge with the light sail method (best current idea, IMNSHO). Just have it so that each section is carrying cargo, so that if a section is lost due to damage the whole ship isn't lost, rather just that one section.

Jon Miller

[Ned]

Originally posted by Dauphin
The energy released in an impact (assuming non-relativistic speeds) is proportional to the square of the speed. The count of particles that fall into the 'kill' zone as you increase speed is dependent on the distribution of sizes of particles in the interstella medium. I would not assume proportionality.

If you increase the number of independent launches you increase the chance of a succesful mission.

If you have a 1/3 chance of success on any given mission you will have a ~70% chance of at least one success with 3 ships.

Do the math for us.

Assume three ships. How much faster can they go to get to the same probability of that at least one of them gets through, all other things being equal.

Second, is this maximum velocity proportional to the number of ships? What is the shape of the curve (or line)? Are there diminishing returns or enhanced returns with increasing numbers of ships?

[Ned]

Originally posted by Jon Miller
What would b ebest is to have a modular spread out ship... the ships already have to be huge with the light sail method (best current idea, IMNSHO). Just have it so that each section is carrying cargo, so that if a section is lost due to damage the whole ship isn't lost, rather just that one section.

Jon Miller

Sounds like a plan.

The vision I see is a giant sail coupled to a common point and that in turn coupled to numbers of ships each having all or a portion of mission-critical cargo.

[Dauphin]

Originally posted by Ned


Do the math for us.

Assume three ships. How much faster can they go to get to the same probability of that at least one of them gets through, all other things being equal.

Second, is this maximum velocity proportional to the number of ships? What is the shape of the curve (or line)? Are there diminishing returns or enhanced returns with increasing numbers of ships?

Its not just a question of maths, it's a question of physical data being required. We don't have the data.

[Dauphin]

Originally posted by Ned


Sounds like a plan.

The vision I see is a giant sail coupled to a common point and that in turn coupled to numbers of ships each having all or a portion of mission-critical cargo.

I really don't like the concept of coupling. I envisage it being a bit like a train. One carriage gets derailed and the whole thing is a big old wreck regardless.

[Jon Miller]

really? a light sail is spread out... which is an added reason why coupling would be good

the reason why a train causes other derailment is because the other cars are behind it... if the other modules are to the side then (as long as the decoupling occurs) no harm would be done

JM

[Geronimo]

Originally posted by Jon Miller
really? a light sail is spread out... which is an added reason why coupling would be good

the reason why a train causes other derailment is because the other cars are behind it... if the other modules are to the side then (as long as the decoupling occurs) no harm would be done

JM

Doesn't that simply increase the volume of space your vessels end up passing through?

[Jon Miller]

you want a huge volume to have a light sail

I am suggesting distributing the cargo and making it so that if a section has problems, that it is removed from the 'ship'

Jon Miller

[Geronimo]

Originally posted by Jon Miller
you want a huge volume to have a light sail

I am suggesting distributing the cargo and making it so that if a section has problems, that it is removed from the 'ship'

Jon Miller

Ok. Obviously my concept of a light sail is faulty. I thought the light pressure the light sail relies on is provided by lasers that remain at the departure location. Why is a large area needed? is it because there is absolutely no way to make the area of the beam a couple lightyears out smaller than a several football fields?

In any event, I would think that rather than wanting the largest possible area you would want the sail area to be only marginally larger than the smallest achievable beam width. Wouldn't you?

[Dauphin]

If the sail is the largest part then it is the part most likely to be hit, and in such a circumstance having redundant cargoes seems pointless.

You would be better off having redundant sails.

[Jon Miller]

I thought it was clear that the sail would be modular also.

Jon Miller

[Jon Miller]

http://en.wikipedia.org/wiki/Light_sails

JM

[Dauphin]

Originally posted by Jon Miller
I thought it was clear that the sail would be modular also.

Jon Miller

In that case I really don't see the benefit over having independent craft.