You are not logged in.
Getting more advanced day by day up to 1 MW now.Good for accelerating a spacecraft???
Offline
Ummm no. You need the beam to operate for months non-stop, not minutes. You can't do this with a chemical-powerd laser... In any event, a 1MW beam wouldn't be enough to push anything of signigant size anyway.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
What do you mean you can't do this? They are doing it.All you need is a larger fuel supply.
Offline
What do you mean you can't do this? They are doing it.All you need is a larger fuel supply.OOPS sorry I did it twice.
Offline
It isn't practical to fire a high-energy chemical laser for months continuously, the amount of laser fuel required and the heat rejection, much less the thing actually being reliable for that long, would be enormous. An electricity-powerd laser is an absolutely nessesitty for laser propulsion, and that it be either ground or space based, not airborne.
In any event, a laser about 100-200 times as powerful would be required to effect serious laser-sail propulsion, and such a laser is currently beyond practical consideration because of its massive cost.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
So build one on the ground without the plane.
Offline
We can't make lasers that big yet, they would require their own nuclear power plant to operate, you would need several of them (three probobly) for essentially continuous beam firing around the globe, you would need a maneuverable space ship with a solar sail, and to top it off, it won't work well anyway because the atmosphere would scatter the laser beam.
Oh yes, and it would only work when leaving Earth, you couldn't use it to return.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Make a bigger sail to capture the force of the scattered ones.
We can build one on the other planet for a return mission.
Offline
No, the scattering is so severe that much of the beam will be lost in our atmosphere, only a portion will even reach space and be anywhere near focused.
Think of it this way too, that the further away you get the smaller a target you have to focus on from Earth. The Moon is thousands of kilometers wide, but it is only a small disk in our sky. It is 250,000mi away. Mars is millions of miles away, and the the larger planets are several times further then that. The size of the sail you would need would be insane.
And we are a long, long, long long long way from building 10's of megawatts power stations off of Earth, much less trying to cool them or the massive laser.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
It is possible to use a laser to ionise the atmosphere and so allow a particle beam flow through the ionised air.
Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.
Offline
I forget. Did I hear something recently about a solar sail probe. Anyway if NASA can build a solar sail probe then a laser will just give it that much more push. I don’t know how practical chemical lasers are for propulsion though optical momentum exchange. However there are other ways to use the light energy to propel the space craft besides direct momentum exchange. There light can be focused and used as a thermal process or in can be stored and used for electric propulsion. I am not sure how large the ship would have to be to collect a reasonable fraction of the laser beam energy. I agree that aiming it sounds like quite the difficult control problem. As a comparison we should look at the positing accuracy of ground and space based telescopes. We should also look at how accurately we NASA has been able to determine the position of its various probes.
Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]
Offline
The biggest problem with using a charged particle beam for propulsion is that the natural solar and planetary magnetic fields will distort the beams' path, and that it is difficult to make the beam focused over very long distances. The atmospheric scattering is a big but secondary concern. Simply ionizing the atmosphere won't improve the scattering effect, and it would probobly make it worse. Using a neuteral particle beam eliminates the magnetic field bending problem, but creates another problem of capturing the beam, that there isn't any easy way to do this.
You would obviously need a solar sail to be a mirror big enough to use a laser for light pressure propulsion, but for any light-beam-powerd system the trouble is the atmosphere will scatter the laser beam too, so the beam generator would have to be either insanely powerful or be based in space. Either aproach would be extremely expensive.
As far as using other methods to capture laser beam energy, you could build a massive solar collector to power an ion engine, but I think that this scheme may be pretty risky compared to an onboard reactor nor would it be able to operate continuously. Using the laser for thermal heating doesn't make a great deal of sense since you are still ultimatly limited by how hot your heating element can become, so this method will have a pretty low maximum efficency.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Solar powered and space or moon based could work.
Offline
Okay, please fill me in about how much several (say, three or four) giant lasers will cost to build and ship to the Moon? If they are, lets say, in the region of 50-100MW each... then you'll need a massive powerplant able to generate around a gigawatt, each. (a gigawatt of solar panels would be really really huge by the way)
Oh, and don't forget, the laser-sail-vehicle will be one direction only: away from the Moon. You can't use it for a return trip.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Build one on Mars Moon for a return trip back.How many acres of Solar Panels will it take on the moons surface?
Offline
Uh huh... so, you want to build multiple >100 megawatt lasers on Mars for the return trip. The amount of solar pannels you would need would be insane, since Mars gets only about 1/3rd of the light as Earth does, and it would be unrelalible because of the dust. You would definatly have to bring a nuclear reactor along, somewhere in the gigawatt range. The biggest proposed space reactor is about 1/1,000th this size, and the only one in development is 1/10,000th of this size.
There is no practical way to power such a laser... Oh, and a conventional solid core reactor would only have enough fuel to power the laser for a few trips.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
No atmosphere on Mars moon so you should get more solar power than if you were on Mars. You could build a reactor once you are there so you don't have to bring one with you.You could also refuel the reactor from Mars fuel or Mars moon fuel.
Offline
Actually no, the Martian moons don't get much more sunlight, they still only get about 1/3rd too. Its because Mars is much further from the Sun then we are.
Building a reactor of that kind of power would be a vast investment. It would have to be about as powerful as a commertial reactor here on Earth, which means it will be huge. And thats not counting the massive radiators you would need, since you don't have a handy supply of cooling water.
And to check off another item on the list you don't have, there are no Uranium mines on Mars, and Uranium mining requires a great deal of water. This is providing there is any Uranium on the tectonicly inactive and bone-dry (Uranium is carried by water in the crust) crust. And then you need the Uranium refining factory, which is a massive undertaking. Oh, and refueling a liquid sodium cooled reactor would not be an easy task either.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Nope, solar would be better. More solar energy would reach Mars moons because there is no atmosphere to block out the solar radiation. Mars atmosphere would make solar power less effecient.
Offline
That just isn't true Errorist, the Martian moons don't get much more sunlight then Mars itself. Think about it for once, the Martian atmosphere is so thin that its almost non-exsistant, there isn't hardly any air to block the sunlight in the first place.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Ah, but there is some so therfore the moon is a better option.
Offline
But that is really irrelivent, because the size of solar array you would need would be vast. Huge. Gigantic. Much bigger then you would want to haul... and you would need several of them since the moons rotate and eclipse.
Lets see, if Phobos/Deimos get about 33% as much light as the Earth does at this distance from the sun, which is about 1400W/m^2. Since you need about 1,000MW to power your laser, and the best arrays are ~30% efficent, so you will need a square array about Three Kilometers on a side. And that is if it is sun-tracking, if it isn't, you'll need about double that array again.
For comparison, when the ISS is finished, its huge solar pannels will generate about 0.2MW. In Mars orbit, they would generate only around 0.06MW.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
So use the luner material once you get there so you won't have to haul it with you.
Offline
Those moons are asteroids, which are mostly metal, instead of like the Moon which is coverd in silicon-bearing dusts, so there may not be any materials to make solar cells of. No supply of Gallium, Arsensic, or Boron for P/N dopants either. No materials to build the giant laser with either, like all the glass you would need. But more then all that...
YOU WOULD NEED A SOLAR PANEL FACTORY! A HUGE one, capable of producing more cells then all the panel factories on Earth combined, and do it in space, and install plus maintain the panels set up.
The scale of this project is just silly Errorist, a solar array about 30m/100ft tall would have to be six hundred kilometers long, which now you have the problem that the asteroids are too small to put your arrays on.
And don't forget, you would need at least two such laser stations for continuous beam operation.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
So build them all the way around the circumference.
Offline