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That's for robotic spacecraft. With humans aboard, they're projecting a month.
".45 ACP - because shooting twice is just silly" - JSOP, 2010
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You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
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When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013
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Because of the greater size (and mass) of the craft.
Decrease the belief in God, and you increase the numbers of those who wish to play at being God by being “society’s supervisors,” who deny the existence of divine standards, but are very serious about imposing their own standards on society.-Neal A. Maxwell
You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun
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Indeed - but since a survivable arrival requires pretty much the same energy to slow down and land as it takes to take off and fly to mars what he has really designed is a way of bombarding mars with very high speed projectiles.
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Duncan Edwards Jones wrote: what he has really designed is a way of bombarding mars with very high speed projectiles.
All you have to do is fly there normal speed once, setup a laser on the surface that can then be used to slow down all future flights.
There are only 10 types of people in the world, those who understand binary and those who don't.
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You can use the same laser to slow down!
Seriously: you cut your sail in two - a big outer ring, and a smaller inner one.
The spacecraft then turns round and the big sail focusses the laser on to the smaller sail. Yes, it gets accelerated and disappeared, but it can be arranged to slow the craft enough to land.
IIRC, Robert L Forward used it in his novel "Flight of the Dragonfly".
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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OriginalGriff wrote: Robert L Forward used it in his novel "Flight of the Dragonfly".
Beat me to it.
Software Zen: delete this;
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Problem with your physics?
The momentum from the laser needs to be reversed by the large sail. You can't do what you want to do.
Here's why: Let the momentum of the laser photons be p. For the big sail to simply absorb all of the momentum would transfer p to the sail in the same direction. Now, for the sale to re-emit that energy in the opposite direction, it would have to make it the zero-sum game that conservation of momentum demands (classical physics and all that), so now you've 2p momentum driving it forward. This energy, reflected to your smaller sail, absorbs it and it only gets p energy back in the other direction. So - you just doubled the forward speed of the ship.
If you want to reflect the light off of the little mirror, too, then you end up with a net 0: nothing happens.
Damn stinking laws of physics! You need that second deathray at the destination side for this to work.
| "The difference between genius and stupidity is that genius has its limits." - Albert Einstein | | "As far as we know, our computer has never had an undetected error." - Weisert | | "If you are searching for perfection in others, then you seek disappointment. If you are seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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No, because the two sails are no longer attached to one another. The big one accelerates off into the distance, slowing the smaller one via the reflected photons.
Think of two boats: one with a sail, and one with a fan. The fan blows the sail away from it as a byproduct of accelerating the boat it is on.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I didn't notice anything in your original about detaching one of the sails. It was two pieces, but my visualization was different because of the missing word.
OK: the detached sail must remain in front of the craft to work. It's accelerated away very rapidly (w/2p force) as it reflects the light. The sail moves away rapidly but the p acceleration it is transmitted to the craft. Both are less massive, making the velocity change more dramatic. The two sails will separate rather quickly!
You are no longer violating laws of physics and may have your CP Points back (check, they're already back).
:SSM
| "The difference between genius and stupidity is that genius has its limits." - Albert Einstein | | "As far as we know, our computer has never had an undetected error." - Weisert | | "If you are searching for perfection in others, then you seek disappointment. If you are seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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I hadn't noticed they had gone! 
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Duncan Edwards Jones wrote: what he has really designed is a way of bombarding mars with very high speed projectiles.
WE ARE SAVED !!![^]
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I take it that is 1.5 days of acceleration and 1.5 days of deceleration?
I really enjoyed Rendezvous With Rama(I think the second novel) where this idea of needing time to decelerate when travelling near light speed is explained fairly well.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
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Quote: I take it that is 1.5 days of acceleration and 1.5 days of deceleration?
I assume so! If you pull the same g-force slowing down as speeding up, slowing down and speeding up should take the same time, of course.
Get me coffee and no one gets hurt!
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If we can technically make it in 3 days; we can make it in a couple of weeks safely for humans; which is a big step from actual predictions.
I'd rather be phishing!
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So it was decided to build three ships, three Arks in space.
So the idea was that into the first ship, the A Ship, would go all the brilliant leaders...
The scientists... The great artists, you know, all the achievers. And then, into the third ship, the C Ship, would go all the people who did the actual work; who made things and did things you see. And then in the B Ship (that's us) - would go everyone else, the middlemen you see.
And so we were sent off first...
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Hell, I'd be happy with a system that gets me to work faster. 
"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle
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I bet you'd be faster with a laser frying your behind 
GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)
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You have a point there! 
"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle
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And the other end of the laser is pointing where?
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Used to be $25, then they upped it to $35, and now to $49. Seems as if they are pushing people into subscribing to Prime.
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We had a £10 to £20 increase recently, too.
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*Cynicism Alert*
Well, they have to pay tax now, so they have to do something to recoup their "losses" - the directors must be allowed to remain in their mansions and be allowed to continue taking holidays in the Caribbean on their yachts. 
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I have Netflix and some of the shows I watch on Netflix are not available on Amazon. Also Amazon prime music does not have an app for the Windows phone, and Amazon prime video does not have an app for Samsung Smart TVs. Kinda show stoppers for me really.
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