A new use for the ISS |
A new use for the ISS |
Jul 12 2008, 10:25 PM
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#1
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The Poet Dude Group: Moderator Posts: 5551 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60 |
I know there's about as much chance of this happening as there is of Keira Knightley ringing me up and asking me to show her the stars on the next clear night, but what a wonderful, wonderful idea...
Moving the ISS -------------------- |
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Jul 12 2008, 11:07 PM
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#2
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
"There are good answers to all these objections."
There are not. "How likely is any of this to happen? Not very" Thank god. He doesn't understand one iota of the challenges involved. 419,000 kg when finished Let's guess a conventional ( rather than months-in-the-van-allen-belts ion ) ISP - 390s http://www.strout.net/info/science/delta-v/intro.html suggests 4.1km/sec required You would need something like 16,000,000,000 kg of fuel. 16 MILLION tons. A fully laden Saturn V rocket on the pad carried 2,708 tons of fuel. It had a max payload of 118 tons. Let's go optimistic - lets say it's a 1600 ISP Ion engine. The requirement then is just 5,000 tons. 42 Saturn V launched laden with Xenon. Someone please check the numbers on that - they may well be orders of magnitude off - but they do, to me at least, seem to be in the right sort of 'bloody stupid idea' ball park. The phrase ' hand waving over the details ' has never been more appropriate |
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Jul 12 2008, 11:39 PM
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#3
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Member Group: Members Posts: 128 Joined: 10-December 06 From: Atlanta Member No.: 1472 |
Someone please check the numbers on that - they may well be orders of magnitude off - but they do, to me at least, seem to be in the right sort of 'bloody stupid idea' ball park. Given delta_v 4100 m/s, exhaust velocity of v_e=Isp*g=390*9.8=3800 m/s, the amount of propellant needed is m = m0*(exp(delta_v/v_e)-1)=814 tons. Ignoring the weight of the propellant tanks and rocket engines and millions other engineering problems, this is just 7 or 8 Saturn 5 launches! |
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Jul 12 2008, 11:48 PM
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#4
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Newbie Group: Members Posts: 3 Joined: 28-June 08 Member No.: 4245 |
Siravan, youre right!
I confounded fuel with total mass, what a shame . Its ~800 tons of chemical fuel and ~125 tons of Xe. |
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