another "potentially habitable" exoplanet: HD 8551

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Fnord
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26 Aug 2011, 11:34 pm

androbot2084 wrote:
10 percent of the speed of light or 67 million miles per hour was the limitation of 1960's starship designs. With today's technology of lighter and smaller hydrogen bombs, lightweight metals, multiple stages, computer designed detonation chambers, and laser thermonuclear ignition, etc, etc. it should be possible to design a starship that can go much faster using technology available to us today and reach its destination in a reasonable amount of time say 40 years and still stay within budget of 1.5 trillion dollars.

... Theoretically speaking, of course!

We've yet to see even one such ship being built, tested, and demonstrated.


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androbot2084
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26 Aug 2011, 11:57 pm

A model atomic rocket was built and flight tested in 1958 as a proof of concept project. This convinced most of the disbelievers including Wernher Von Braun who originally thought that exploding an atomic bomb would blow up the ship.



ruveyn
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27 Aug 2011, 4:25 am

androbot2084 wrote:
A model atomic rocket was built and flight tested in 1958 as a proof of concept project. This convinced most of the disbelievers including Wernher Von Braun who originally thought that exploding an atomic bomb would blow up the ship.


Can you really believe that a ship built by the lowest bidder will be able to run trouble free for 20 years? Really? Once the ship is Out There there is no way of handling a -real emergency-. No dry dock. No repair crew. Few spare parts. And just how fast do you think the thing will go before relativistic mass overwhelms the energy supply?

And why do you think the rest of us will be willing to invest large sums of money (which really means labor and time) in a project that -if- successful will benefit only a few hundred or a few thousand of the human race? To build a star ship would require taxing the U.S. into poverty and there is only a small chance that it would work.

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Tom_Kakes
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27 Aug 2011, 5:52 am

androbot2084 wrote:
A model atomic rocket was built and flight tested in 1958 as a proof of concept project. This convinced most of the disbelievers including Wernher Von Braun who originally thought that exploding an atomic bomb would blow up the ship.


The so called "proof of concept" was a dish, a pole and some dynamite. Atomic rockets are not a viable concept for human space flight. Maybe a probe could be designed is such a way. We couldn't even get 40 years worth of food into orbit. Let alone oxygen and super heavy nuclear material .



DeaconBlues
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27 Aug 2011, 10:59 am

Since the concepts have been proven, though, getting them to function properly is a matter of engineering, not basic science.

There would appear to be no reason to overcome the engineering challenges until an actually human-habitable exoplanet is discovered, however - even Gliese 581d would have you massing 2.5x your proper Earth weight, in an atmosphere consisting largely of carbon dioxide, orbiting a K-class star (markedly dimmer than our own Sun) on the outer edge of its "Goldilocks zone". Why spend billions (at minimum) figuring out how to cross 20 lightyears of space to get to that? And the other candidates thus far are even worse.

If we want to occupy worlds not terribly habitable for humans, we have plenty of those right here in our own solar system, and we know pretty well how to get to them (Mars, for instance, will become much more useful once the company building the VASIMR coupled-charge plasma thruster manages to get up to about 200 kW output, which could be used for a constant-boost manned ship thrusting at about .001g or so - Earth orbit to Mars orbit in 39 days!).


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Jono
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27 Aug 2011, 3:29 pm

Fnord wrote:
If HD85512b is indeed 3.5 times the mass of Earth, a person who weighs 200 pounds on Earth would weigh 700 pounds there, and likely die of a heart attack from trying to stand up.

So much for being "Habitable".


By "habitable", we usually mean that life could potentially evolve there, not that we would survive if we visited. I'm sure any life on HD85512b would be adapted to the high gravity.



ruveyn
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27 Aug 2011, 6:39 pm

androbot2084 wrote:
10 percent of the speed of light or 67 million miles per hour was the limitation of 1960's starship designs. With today's technology of lighter and smaller hydrogen bombs, lightweight metals, multiple stages, computer designed detonation chambers, and laser thermonuclear ignition, etc, etc. it should be possible to design a starship that can go much faster using technology available to us today and reach its destination in a reasonable amount of time say 40 years and still stay within budget of 1.5 trillion dollars.


Are you taking into account the increase in relativistic mass?

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androbot2084
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27 Aug 2011, 7:07 pm

Black hole power ought to do the job. Nuclear pulse propulsion will be used to build the infrastructure



graywyvern
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29 Aug 2011, 11:15 am

left off a digit! yes, it's HD 85512 b (i prefer the name Gliese 370, which is easier to remember; this star is also known as HIP 48331--in the Hipparcos catalog--& CD -42' 5678, where the apostrophe i wrote should be taken as a degree mark.)

by a formula i have for terrestrial-type planets, the gravity actually works out around 1.8 times Earth's--not insupportable for land inhabitants, i should think: though maybe more likely three or four leg-supports, than a mere two.

btw Zarmina has been disputed, sure. but the issue is still in doubt.see: http://arxiv.org/abs/1011.0186http://ar ... /1011.0186
for a differing view: http://adsabs.harvard.edu/abs/2011arXiv1101.0800G

latest on Gliese 581d: http://arxiv.org/abs/1105.1031


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