@joshtigerheart, on Jul 10 2008, 01:56 PM, said in On Relative Sizes of Spacecraft:
Wow, calm thew heck down and reread my post. Key line: "It's just a manner if improving existing technology". I'm not saying we have it now, we'd need to improve current technology to reach it. We have lasers, we just need to make them better and more energy efficient. We have a space station (albeit still under construction) that doesn't get fried by this cosmic bombardment, we just need to miniturize whatever it is using. We have the capability of doing cold fusion, among other potential power generation methods, we just need to devise a way to make the energy output higher than the energy input. We have spacecraft now, we just need to take all of the above, improve them to reach whatever standards would be required, and combine them into a spaceship.
There's a reason why sci-fi typically doesn't take place tomorrow.
And just to point out, if Nova's methods of generating power for a ship are to be taken as possible to power spacecraft, then we already can do two methods in a cost-effective manner: solar panels and fission reactors (though the latter isn't entirely safe yet).
@lnsu, on Jul 10 2008, 04:48 PM, said in On Relative Sizes of Spacecraft:
There are already fission-powered submarines and warships, and I have yet to hear of a meltdown onboard a sub/warship. Mind you, I haven't done my research, so feel free to prove me wrong. Its just a matter of making one big enough and making a rocket big enough to launch it into space.
@archon, on Jul 10 2008, 04:49 PM, said in On Relative Sizes of Spacecraft:
Dude Swithich, relax. And you may want to take Josh's advice regarding the post too.
@ue_research---development, on Jul 10 2008, 07:19 PM, said in On Relative Sizes of Spacecraft:
The US Navy has been operating nuclear-powered ships for decades now without a single ship lost due to the reactor melting down or malfunctioning. (At the same time, Russia has suffered several severe accidents.) So it's really a question of discipline and adherence to proper operating procedures, not whether or not nukes are mysterious magical black boxes that might blow up if the planets are misaligned.
@joshtigerheart, on Jul 10 2008, 09:11 PM, said in On Relative Sizes of Spacecraft:
I blame a lack of research on the safety of nuclear fission in combination with the media's portrayal of them and their meltdowns. On the other hand, my post shouldn't be taken to mean I think meltdowns are frequent, just a possibility.
@0101181920, on Jul 10 2008, 10:47 PM, said in On Relative Sizes of Spacecraft:
In reality, fission reactors are mostly safe. Long Island. Huge accident. Why? Something failed. I forget what, but alarms went off. The trouble was that there were too many alarms. Safety systems, safety systems on the safety systems, for everything. Something was always going wrong. It goes down two degrees, an alarm goes off. So the technicians reset the alarm and ignored it. There was almost always an alarm going off. By the time they figured it out, it was too late. Chernobyl. Human error.
The point of this is that humans are generally the weak link in any dangerous system. We do something wrong, go to the bathroom at the wrong time, press the wrong button, skip a shift, raise all the control rods (Chernobyl.) If humans payed attention to it, we don't need to worry about fission reactors or fusion or whatever. Even if something does malfunction, then it can be shut off in time.
Just so you all know that ! meant excitement, not anger (actually get very excited when I get to argue points...because in my family, people just shut me down, they'd rather be wrong and go about their lives, then learn the right answer and correct their mistakes).
Okay so lets go over some things. As I stated there is still no way of protecting from cosmic ray bombardment. The ISS has no system for doing so. It uses the Earth's own magnetic field for some protection, but to be honest if a large enough cosmic ray bombardment occurred, the astronauts we have in space, would be fried (the magnetic field fluctuates meaning you can actually move outside of it, if you are in a low orbit). It is also helpful to note that only a select few humans have ever ventured outside of a stellar magnetic field. That would be the Apollo missions, for a day or two when they were going between the moon and earth (both of which have magnetic fields). Going to Mars or anywhere else in the universe means at this time, an unprotected human being in a small capsule.
Now on the topic of fission reactors. It has been suggested to put fission reactors into space...okay. There are a few issues with that (and these are why it generally hasn't been done). So you send a rocket into space with exposed nuclear (radioactive) material...what if it doesn't make it, you run the risk of raining down radioactive particles on a lot of people and having them in the upper atmosphere...which is bad juju (same with reentry of a spacestation if you have extra fuel) Second, fission reactors are extremely heavy...basically they work by circulate water by heating it to a boil, running that through a gas turbine, cooling, and repeating. That whole setup is huge, and thus up until very very recently all nuclear power plants have been 1000 MW or larger. Even on military ships fission generators take up a large portion of the ship (aka. the submarine, carrier, or battleship). More importantly launching such a large quantity mass (and dense as well, Uranium/Plutonium are extremely dense) would be difficult once you include support systems, lasers, engines, fuel for engines...etc.
I think that is why a moon base (the moon has large quantities of Plutonium and Helium-3, a very unstable atom that radiates energy...in process needed...or that is the theory) is so important. Also it would take less energy to launch a vehicle from the moon...because less gravity, plus the moon gives an extra speed boost and is close to anywhere humans might want to go.
Now on the fission reactors. All accidents with fission (nuclear) reactors have occurred with first or second generation nuclear reactors. Aka, plutonium cookers. Basically what Hanford is. Such reactors were designed in the 50s and 60s, when we were still testing exactly what fission did. Fast forward to today. All new plans for reactors would probably a generation 3+ reactor (that is right we skipped generation 3 in the United States all together) and possibly 6 generation 4 reactors (chosen as the 6 most innovative from a list of hundreds of generation 3+ reactors by nuclear engineers and scientists), which are currently under testing. This stuff is really cool and I could go on for hours, but I will get to the punch line. generation 3 and later reactors have the benefit of their designs being extremely safe as well as durable. They also have the benefit of 50 or 60 years of nuclear research and thus a better understanding of who systems work. The accidents at 3 mile island and Chernobyl would never happen with todays reactors, they just wouldn't. With the new generation 4 reactors, nuclear reactor are moving away from their roots. Many have higher output exhausts (great for splitting water and making h2 for our cars in the future), several don't even use water to cool the reactors (instead using liquid lead and salt to cool the reactors), and some use a form of fuel encased in granite, which can be used to make smaller and less harmful reactors (even if they blew up...somehow you'd just have little granite encased uranium or plutonium.
Anyway here is the wiki, http://en.wikipedia....tion_IV_reactor. Really cool stuff though. Today's and the future's nuclear reactors are shadows of their former selves and that is for the better.
Anyhow I could talk all day about stuff like this, but I really should go to bed. See you all later.
Now on the safety issues.