I think that Mathematicians largely arent the philanthropists that scientists are.
However, seeing as how every science consists largely of mathematical models, the ends justify the means, so to speak.
In other words, while a mathematician isnt looking for a way to make a longer lasting lightbulb, his or her ideas eventually work their way into science and engineering applications, even if it takes decades to happen.
Actually there are two main types of nuclear propulsion...
Nuclear Thermal Propulsion (NTP) - Heat hydrogen and pass it by the reactor to heat it, then expel it.
Nuclear Electric Propulsion (NEP) - Ion propulsion, like Deep Space 1, except you have much more energy with a nuclear reactor than you would with solar arrays of a feasible size.
Both these methods are more efficient than chemical propulsion. NTP has much higher thrust than NEP, but NEP is much more efficient than NTP. So itll take longer to get where youre going with NEP, but youll use less propellant.
JIMO is using NEP, not NTP. To my knowledge, NTP has yet to be tested in space, although its been tested many times on the ground.
Take Xenon or Krypton, use some electrical energy to ionize it, and use some more electrical energy to propel the ions out the back of your spacecraft much faster than you could ever propel the products of chemical combustion. Thus you get more momentum, gram for gram of propellant, than you would get from chemical propulsion.
Solar electric propulsion has been done before, such as Deep Space 1. But for going out to Jupiter with such a large payload, the Sun's energy is just not enough.
The radiation environment at Europa is a challenge to design around. Sending the craft to Io would probably require so much more radiation shielding for the electronics (ie weight) as to make the mission infeasible.
Also, recent studies have indicated that Callisto and Ganymede might contain subterranean water, making the possibility of life greater there than at Io.
Please use WV when referring to West Virginia. W.Va. has been deprecated, as it makes it seem as if the state is just a section of Virginia.
Why a "sustained gentle push" probably wont help.
on
Stopping Killer Asteroids
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· Score: 2, Interesting
I've studied this problem before. The amount of sustained thrust you need, given several years advanced notice, assuming a ~1km diameter asteroid, is on the order of hundreds of Newtons. More than an energy beam could provide. The mass driver isnt a bad idea, BUT the most efficient thrust vector to change the asteroids orbit is along its velocity vector. Asteroids tend to spin on an inertially fixed axis, so you would have to put your thrust along that axis as well. In doing so you waste a lot of thrust.
Last year was the first year I tried using my digital camera (Olympus C3000) to catch the show, leaving the shutter open for up to 16 seconds.
What I didnt know is that CCD's have a transient response to temperature. Make sure to get out early and allow your camera time to acclimate to the temperature. Otherwise youll get very speckled photos.
The internet connection (at least as of my graduation in May) was OC3. However, the university has to pay per bandwidth (provided via OARnet), so it was actually at something around 25-35Mb/s. Not sure exactly because there was a period when it was constantly getting upped due to P2P hogging the pipe.
What this paper states (incorrectly) is that it is not the gravitational forces alone that cancel each other out, but the combination of gravitational forces and centripetal acceleration cancelling each other out.
Suggest you do a google search on the Circular Restricted Three Body Problem (CRTBP)
That Mars is also undergoing global warming without input from humans? Perhaps the Suns energy output is on the upswing. Would think that would be easily detectable though.
Slashdot Mirror
If I recall 1N of force requires 1kmx1km of sail. I might be off by an order of magnitude though.
I think that Mathematicians largely arent the philanthropists that scientists are.
However, seeing as how every science consists largely of mathematical models, the ends justify the means, so to speak.
In other words, while a mathematician isnt looking for a way to make a longer lasting lightbulb, his or her ideas eventually work their way into science and engineering applications, even if it takes decades to happen.
the phone automatically buys a few shares of Nokia's stock
Actually there are two main types of nuclear propulsion...
Nuclear Thermal Propulsion (NTP) - Heat hydrogen and pass it by the reactor to heat it, then expel it.
Nuclear Electric Propulsion (NEP) - Ion propulsion, like Deep Space 1, except you have much more energy with a nuclear reactor than you would with solar arrays of a feasible size.
Both these methods are more efficient than chemical propulsion. NTP has much higher thrust than NEP, but NEP is much more efficient than NTP. So itll take longer to get where youre going with NEP, but youll use less propellant.
JIMO is using NEP, not NTP. To my knowledge, NTP has yet to be tested in space, although its been tested many times on the ground.
Electric Propulsion (Ion Propulsion)
Take Xenon or Krypton, use some electrical energy to ionize it, and use some more electrical energy to propel the ions out the back of your spacecraft much faster than you could ever propel the products of chemical combustion. Thus you get more momentum, gram for gram of propellant, than you would get from chemical propulsion.
Solar electric propulsion has been done before, such as Deep Space 1. But for going out to Jupiter with such a large payload, the Sun's energy is just not enough.
Voyager 1 and 2, and pretty much every other spacecraft thats every gone out beyond Mars' orbit has been powered by RTGs.
The radiation environment at Europa is a challenge to design around. Sending the craft to Io would probably require so much more radiation shielding for the electronics (ie weight) as to make the mission infeasible.
Also, recent studies have indicated that Callisto and Ganymede might contain subterranean water, making the possibility of life greater there than at Io.
Insert token wisecrack about English/Metric conversion here
I wasnt aware that toners were digital media.
The real world needs intrinsic matrix operations too. :)
Itll happen.
You guys quit the Union. We werent down with that. What else were we to do.
BTW Im originally from Wheeling, the first capital of the state.
For future reference:
Please use WV when referring to West Virginia. W.Va. has been deprecated, as it makes it seem as if the state is just a section of Virginia.
I've studied this problem before. The amount of sustained thrust you need, given several years advanced notice, assuming a ~1km diameter asteroid, is on the order of hundreds of Newtons. More than an energy beam could provide. The mass driver isnt a bad idea, BUT the most efficient thrust vector to change the asteroids orbit is along its velocity vector. Asteroids tend to spin on an inertially fixed axis, so you would have to put your thrust along that axis as well. In doing so you waste a lot of thrust.
I verified it by leaving the lens cap on. No speckles indoors when the camera was warm, speckles outside when the camera was getting cold.
Last year was the first year I tried using my digital camera (Olympus C3000) to catch the show, leaving the shutter open for up to 16 seconds.
What I didnt know is that CCD's have a transient response to temperature. Make sure to get out early and allow your camera time to acclimate to the temperature. Otherwise youll get very speckled photos.
Also keep in mind though that any sizable asteroid is going to be several orders of magnitude more massive than 1000000 t
TO deflect any sizable asteroid (>1km diameter) will take years even with relatively large levels of thrust.
I cant see lasers helping all that much.
Does this mean someday you'll be able to query the monitor to determine what data is being displayed, rather than doing it through software?
We're going to need a new standard Fortran record number
I'd think any patent that uses phrases like "a variety of" is too vague.
Yes it still has its place. Programs like Matlab have gotten more popular, but theyre expensive.
I for one cant wait for g95 to be released. link
The internet connection (at least as of my graduation in May) was OC3. However, the university has to pay per bandwidth (provided via OARnet), so it was actually at something around 25-35Mb/s. Not sure exactly because there was a period when it was constantly getting upped due to P2P hogging the pipe.
What this paper states (incorrectly) is that it is not the gravitational forces alone that cancel each other out, but the combination of gravitational forces and centripetal acceleration cancelling each other out.
Suggest you do a google search on the Circular Restricted Three Body Problem (CRTBP)
That Mars is also undergoing global warming without input from humans? Perhaps the Suns energy output is on the upswing. Would think that would be easily detectable though.
Maglev Launch helps too
Sure it wont get you to Mach-5, but its fuel you dont have to carry