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To Mars and Back in Ninety Days
paltemalte writes "A new means of propelling spacecraft being developed at the University of Washington could dramatically cut the time needed for astronauts to travel to and from Mars and could make humans a permanent fixture in space. In fact, with magnetized-beam plasma propulsion, or mag-beam, quick trips to distant parts of the solar system could become routine, said Robert Winglee, a UW Earth and space sciences professor who is leading the project."
This is fine and well, but how does one meanwhile solves the most pressing problem, that is, providing CHEAP and RELIABLE means to get into earth orbit???
Sign me up, should this ever become a reality. However, the only way space travel will become an everyday occrance is if it is profitable. Don't get me wrong. I'd love to do it for the sake of doing it. But people aren't willing to spend millions/billions/trillions of dollars to do something just because "its there".
/. is a bunch of nerds at a million typewriters. It's not a political conspiracy determined to undermine your beliefs.
Hope they can slow it down when they get there.
/will probably make a small crater...
Check out my sysadmin blog!
What's all this about a "new method" being required for short trips to Mars? What about the 101 old methods we have? Nuclear Thermal, Nuclear Electric, Orion, Laser Lifters, Nuclear Salt Water (this seriously needs to be developed!), Fission Fragment engines, Nuclear Steam ships, etc, etc, etc.
We've got high powered propulsion options pouring out of our ears. It all comes down to getting funding. Wave a plan near congress and they're sure to kill it before breakfast.
Javascript + Nintendo DSi = DSiCade
You could build a rocket with a boiler that burned pieces of the ISS. At least *that* would be putting it to good use...
Oh! Sh!t we shoot the cabin insteed of the sail !
Ceci n'est pas une Signature !
That should be "at what Delta-V?" More Delta-V == faster.
Javascript + Nintendo DSi = DSiCade
What are they looking at in creating particle or at least micrometeorite ablative shielding that can handle the increased velocity these hazards will bring with the increased speeds?
right now our spacecraft are basically beer cans with insualtion and windows, any tiny object at any decent velocity can rip through them like tissue paper. on a long distance mission as a trip to mars would be, we need a craft that is at least 100 times stronger than anything we launch now which would make it more than that many times heavier.
Do not look at laser with remaining good eye.
I poo-poo your silly idea Philleas Fog.. It's impossible and I'll wager my reputation that you won't make it from the Gentleman's Club in London to Mars and back within 90 days!
"Rather than a spacecraft having to carry these big powerful propulsion units, you can have much smaller payloads,"
.sig, but I'm not going to give it to you.
If the station fails at the remote end, will it take 40 years to get back to earth?
I have a great
So, you mean that I could get something to and from Mars in under 90 days? That's better time than the US takes to process my tax return. I wonder when Mailboxes Etc will set up a PO Box service on mars? Could be a whole growth opportunity.
Or maybe I shouldn't post to slashdot before morning coffee.
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I hate to be a buzzkill, but is there ANY realistic reason why sending people to Mars is good science?
It seems that if we spend the money that it would take to develop the spacecraft & lifesupport required to send people that far on better and more reliable robots, a lot more actual research would get done. Heck, we might even have enough left over to fix the Hubble.
Let's work on practical reasons to send people into space at all... then maybe the moon. Billions of tax dollars shouldn't be blown on a project of little scientific validity just because "it's cool."
In Capitalist America, bank robs you!
I barely got the page to load... here's the article text: A new means of propelling spacecraft being developed at the University of Washington could dramatically cut the time needed for astronauts to travel to and from Mars and could make humans a permanent fixture in space. In fact, with magnetized-beam plasma propulsion, or mag-beam, quick trips to distant parts of the solar system could become routine, said Robert Winglee, a UW Earth and space sciences professor who is leading the project. Currently, using conventional technology and adjusting for the orbits of both the Earth and Mars around the sun, it would take astronauts about 2.5 years to travel to Mars, conduct their scientific mission and return. "We're trying to get to Mars and back in 90 days," Winglee said. "Our philosophy is that, if it's going to take two-and-a-half years, the chances of a successful mission are pretty low." Mag-beam is one of 12 proposals that this month began receiving support from the National Aeronautics and Space Administration's Institute for Advanced Concepts. Each gets $75,000 for a six-month study to validate the concept and identify challenges in developing it. Projects that make it through that phase are eligible for as much as $400,000 more over two years. Under the mag-beam concept, a space-based station would generate a stream of magnetized ions that would interact with a magnetic sail on a spacecraft and propel it through the solar system at high speeds that increase with the size of the plasma beam. Winglee estimates that a control nozzle 32 meters wide would generate a plasma beam capable of propelling a spacecraft at 11.7 kilometers per second. That translates to more than 26,000 miles an hour or more than 625,000 miles a day. Mars is an average of 48 million miles from Earth, though the distance can vary greatly depending on where the two planets are in their orbits around the sun. At that distance, a spacecraft traveling 625,000 miles a day would take more than 76 days to get to the red planet. But Winglee is working on ways to devise even greater speeds so the round trip could be accomplished in three months. But to make such high speeds practical, another plasma unit must be stationed on a platform at the other end of the trip to apply brakes to the spacecraft. "Rather than a spacecraft having to carry these big powerful propulsion units, you can have much smaller payloads," he said. Winglee envisions units being placed around the solar system by missions already planned by NASA. One could be used as an integral part of a research mission to Jupiter, for instance, and then left in orbit there when the mission is completed. Units placed farther out in the solar system would use nuclear power to create the ionized plasma; those closer to the sun would be able to use electricity generated by solar panels. The mag-beam concept grew out of an earlier effort Winglee led to develop a system called mini-magnetospheric plasma propulsion. In that system, a plasma bubble would be created around a spacecraft and sail on the solar wind. The mag-beam concept removes reliance on the solar wind, replacing it with a plasma beam that can be controlled for strength and direction. A mag-beam test mission could be possible within five years if financial support remains consistent, he said. The project will be among the topics during the sixth annual NASA Advanced Concepts Institute meeting Tuesday and Wednesday at the Grand Hyatt Hotel in Seattle. The meeting is free and open to the public. Winglee acknowledges that it would take an initial investment of billions of dollars to place stations around the solar system. But once they are in place, their power sources should allow them to generate plasma indefinitely. The system ultimately would reduce spacecraft costs, since individual craft would no longer have to carry their own propulsion systems. They would get up to speed quickly with a strong push from a plasma station, then coast at high speed until they reach their destination, where they would be slowed by another plasma station. "This would facilitate a permanent human presence in space," Winglee said. "That's what we are trying to get to." Love, Tripptdf
A new means of propelling spacecraft being developed at the University of Washington could dramatically cut the time needed for astronauts to travel to and from Mars and could make humans a permanent fixture in space.
In fact, with magnetized-beam plasma propulsion, or mag-beam, quick trips to distant parts of the solar system could become routine, said Robert Winglee, a UW Earth and space sciences professor who is leading the project.
Currently, using conventional technology and adjusting for the orbits of both the Earth and Mars around the sun, it would take astronauts about 2.5 years to travel to Mars, conduct their scientific mission and return.
"We're trying to get to Mars and back in 90 days," Winglee said. "Our philosophy is that, if it's going to take two-and-a-half years, the chances of a successful mission are pretty low."
Mag-beam is one of 12 proposals that this month began receiving support from the National Aeronautics and Space Administration's Institute for Advanced Concepts. Each gets $75,000 for a six-month study to validate the concept and identify challenges in developing it. Projects that make it through that phase are eligible for as much as $400,000 more over two years.
Under the mag-beam concept, a space-based station would generate a stream of magnetized ions that would interact with a magnetic sail on a spacecraft and propel it through the solar system at high speeds that increase with the size of the plasma beam. Winglee estimates that a control nozzle 32 meters wide would generate a plasma beam capable of propelling a spacecraft at 11.7 kilometers per second. That translates to more than 26,000 miles an hour or more than 625,000 miles a day.
Mars is an average of 48 million miles from Earth, though the distance can vary greatly depending on where the two planets are in their orbits around the sun. At that distance, a spacecraft traveling 625,000 miles a day would take more than 76 days to get to the red planet. But Winglee is working on ways to devise even greater speeds so the round trip could be accomplished in three months.
But to make such high speeds practical, another plasma unit must be stationed on a platform at the other end of the trip to apply brakes to the spacecraft.
"Rather than a spacecraft having to carry these big powerful propulsion units, you can have much smaller payloads," he said.
Winglee envisions units being placed around the solar system by missions already planned by NASA. One could be used as an integral part of a research mission to Jupiter, for instance, and then left in orbit there when the mission is completed. Units placed farther out in the solar system would use nuclear power to create the ionized plasma; those closer to the sun would be able to use electricity generated by solar panels.
The mag-beam concept grew out of an earlier effort Winglee led to develop a system called mini-magnetospheric plasma propulsion. In that system, a plasma bubble would be created around a spacecraft and sail on the solar wind. The mag-beam concept removes reliance on the solar wind, replacing it with a plasma beam that can be controlled for strength and direction.
A mag-beam test mission could be possible within five years if financial support remains consistent, he said. The project will be among the topics during the sixth annual NASA Advanced Concepts Institute meeting Tuesday and Wednesday at the Grand Hyatt Hotel in Seattle. The meeting is free and open to the public.
Winglee acknowledges that it would take an initial investment of billions of dollars to place stations around the solar system. But once they are in place, their power sources should allow them to generate plasma indefinitely. The system ultimately would reduce spacecraft costs, since individual craft would no longer have to carry their own propulsion systems. They would get up to speed quickly with a strong push from a plasma station, then coast at high speed until they reach their destination, where they would be slowed by another plasma station.
"This would facilitate a permanent human presence in space," Winglee said. "That's what we are trying to get to."
Wave a plan near congress and they're sure to kill it before breakfast.
Sure they will. The aliens don't want our crap in outer space at least until we can handle our problems like adult persons instead of reacting emotionally to every single difference between us. So, what's better than keep tabs in the govment of the only country that can fund such stuff?
It's better to be the foot on the boot than the face on the pavement. ~~ tkx Kadin2048
Trolling using another account since 2005.
The article mentions having one station here and another on the other side, so that the craft itself need not carry its own propulsion.
However, any sort of malfunction - from the braking side not firing at the right time, to the braking side getting knocked off angle by a micrometeorite at the wrong moment, to the craft itself getting pushed off course - would mean that the craft itself would go hurtling through space with no real chance to be rescued.
The way around this? Keep an on-board propulsion system that's able to slow it down from full-speed back to 0, and then speed it up enough to get back to where you were going originally in a reasonable amount of time.
Which kind of defeats the purpose of the entire method.
That green slime had it coming.
Whose first thought when they saw "magnetized-beam plasma propulsion, or mag-beam" was "I used that in TIE Fighter 10 years ago!"?
:/
Sadly, mine was.
Just send a diplomat to Mars, establish a trade agreement and an alliance with them and build a road.
Then we can quickly invade when they least expect it. When you play enough Rome Total War these things become soooo obvious.
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What truth?
There is no dupe
Working Mirrordot link .
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Speed is relative. Meteors (including micrometeors) often travel 100's of thousands of miles an hour w/respect to the EARTH. A measly 20-40 thousand mph difference in ship speed isn't going to make much difference to one of these bad boys.
- The race is not [always] to the swift, nor the battle to the strong. -
"Under the mag-beam concept, a space-based station would generate a stream of magnetized ions that would interact with a magnetic sail on a spacecraft and propel it through the solar system at high speeds that increase with the size of the plasma beam. Winglee estimates that a control nozzle 32 meters wide would generate a plasma beam capable of propelling a spacecraft at 11.7 kilometers per second."
Would not it also push the space-based station the other way? The whole action-equal-reaction thing they teach in physics?
Has anyone gleaned from the article how the beaming stations are maintained in place?
I got that nuclear and solar power would be used to generate the beam, but generating the beam would impart thrust to the station.
Did I miss something?
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..or at least the brakes. It's not a new plan, though it might be a new flavor. Nivens was talking about laser-based launching stations back in the 70s and he was just taking the most probable solution.
Of course Newton's laws interest me. If you fire an energy beam able to move a 1000kg probe at 11.7km/s, your 10,000kg station is going to be moving 0.117km/s. (261mph)
Then there's the power issue. Exactly what are these orbital launcher going to use for power? I don't see the green club letting enough fissionable materials get up there and otherwise we're looking at a biiiiig solar array tied to some form of energy storage (water/hydrogen/fuelcell?)
I've been on slashdot so long I'm starting to get out of touch with the cool stuff if it ain't on slashdot.
there's particles travelling high speed that might hit you, no matter what speed you're going yourself.
and as such, high speed in this case wouldn't necessarely be 'increased risk'.
if anything, it would be less risk of that(because the trip itself would take less time..).
though, with this and the gazillion other "how to get to mars" plans there's holes in it that haven't been filled.
world was created 5 seconds before this post as it is.
It's not actually that fast. Mars is only about 50 million miles away from us; that means the capsule would need to travel at an average speed of 23,148 miles per hour to achieve this. Assuming acceleration and deceleration were continous, you'd need a peak speed of twice that. Your acceleration figure works out to be about 0.3 miles per hour every minute. You'd hardly feel it.
That should be "at what Delta-V?" More Delta-V == faster.
If, by "Delta-V" you mean "change in velocity," then that would indeed be acceleration -- which doesn't necessarily mean faster.
Think about it: I drive my car from 0 to 60mph in 3 seconds, while yours only goes from 0 to 60mph in 12 seconds. At the end of that time, we're both going the same speed (assuming we stop accelerating once we hit 60mph), but my acceleration was much quicker than yours (4 times as fast, in fact).
Can anyone tell me how the "pusher" satellite in the picture is supposed to work? I see one beam of energy with enough force to accelerate a spacecraft with a lot of force. Either there's an invisible other beam balancing this out, scorching the Earth underneath, or the satellite is doing a much better job of propelling itself out of the solar system than it is pushing the distant spacecraft where it's supposed to go. Or has someone figured out how to suspend Newton's second law?
The big "breakthtrough" here is to decouple the propulsion system (the plasma beam) from the spacecraft. That makes the craft smaller and lighter since it doesn't have to move all that fuel around.
HOWEVER...
This system requires having another plasm beam generator to "catch" the spacecraft and slow it down with another plasma beam. That means not only sending the generator platform to Mars, but also all of the material from which to make the plasma (most likely nitrogen or one of the heavier noble gases). The generator platform needs a power source capable of sustaing the creating and acceleration of the plasma beam, which means nuclear, and a fission nuclear reaction, not radiothermic generation. All of that means a technically complex space station, with people to keep it running. To have such a system in Earth orbit would be tough enough. The cost and difficulty of shipping all of that material out to a Mars orbit, and maintaining it so it will be ready to deccelerate an incoming spacecraft would be Absolutely Enormous.
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Early space related centrifuge tests performed at WADC
In 1952, E. R. Ballinger, leader of the research program at Wright-Patterson, conducted one of the earliest series of centrifuge tests directed expressly toward the problem of g forces in space flight. Ballinger found that 3 g applied transversely would be the ideal takeoff pattern from the physiological standpoint, but he realized that the rocket burning time and velocity for such a pattern would be insufficient to propel a spacecraft out of the atmosphere. Consequently he and his associates subjected men to gradually increasing g loads, building to peaks of 10 g for something over two minutes. Chest pain, shortness of breath, and occasional loss of consciousness were the symptoms of those subjected to the higher g loads. The tests led Ballinger to the conclusion that 8 g represented the acceleration safety limit for a space passenger.
They will have to spread the acceleration and deceleration down over a few miles
And no, spacecraft right now are NOT beer cans. They contain an outer shell, and several layers of different material to prevent micrometeriods from penetrating the pressure hull. Windows are specially designed, and if you pay attention to photographs from spacecraft you would see tons of scratches on the outer surface.
Guess what they are from?
"Learning is not compulsory... neither is survival."
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D'oh. Round trip, not single direction. Double my figures; 0.6 miles per hour per minute.
It's all about weight.
The reason our spaceships are tin cans is because nobody can afford the weight for shielding. When 99+% of your mass is thrown away, carrying an extra kilo at the end means an extra hundred kilos at the start.
But, if you have a good enough fuel that you only need 10 times your ultimate mass in fuel, suddenly you can carry shielding. The better your specific impulse (I_sp = pounds of thrust per pound of fuel used per second), the better your chances for shielding. An I_sp of 200 (about what http://armadilloaerospace.com/ hoped to achieve) means you're just barely cutting it. An I_sp of around 300 makes life a lot easier, but that pretty much requires liquid hydrogen/liquid oxygen.
Anything higher than that is just pure nirvana for the rocket guys. I have heard of I_sp of over 1000 from a cesium ion drive, but that had just a teensy thrust, making it useful only for satellite station keeping.
So, in conclusion, if you can get a high I_sp and a high thrust, then shielding is a piece of cake.
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>Winglee envisions units being placed around the
>solar system by missions already planned by NASA.
>One could be used as an integral part of a research
>mission to Jupiter, for instance, and then left
>in orbit.
This ignores Newton's law that for every action there is an equal and opposite reaction.
According to Newton if the transitter unit isn't fixed to something big and heavy (i.e. a planet) it would also propel itself backwards (and out of position) at an inversely proportional acceleration rate to the spaceship.
For perspective, to the Moon and back in a day with plenty of time to have a picnic.
You are in error. No-one is screaming. Thank you for your cooperation.
Do not trust the pusher satellite. Pushing will protect you from the terrible secret of space. Do you have stairs at your house?
Stop learning! Only you can prevent esoterrorism.
2: How are you going to point it? Minute differences in direction on launch will determine whether you go into orbit around Mars or crash into Jupiter.
3: Not all planets have substantial magnetic fields (such as Venus)
4: The acceleration that would result if you could get this working would liquefy any human.
5: Sound != electromagnetic radiation.
Scientists have come up with a cheap and reusable method of getting to orbit and traveling about the cosmose. Utilizing the effect of slashdotting a website, we beam those hits against a reflective matterial on the space craft that will allow network packets to propell it in to orbit and beyond. To slow down a craft ariving at it's destination, a special set of mirrors will be setup to redirect traffic to the front of the ship where another reflector will slow down the craft...
~~ Behold the flying cow with a rail gun! ~~
A NERVA, starting from LEO could match that speed with a mass ratio of 2.7 or thereabouts.
In other words, it's not really terribly fast by the standards of the solar system.
"I do not agree with what you say, but I will defend to the death your right to say it"
What happens if you're jetting at 26,000 mph, and the braking system fails. You'll be doing a David Bowie - "Major Tom, it's been nice knowing you!"
They've got to have a serious stash of fuel on board for the "Holy $@%^%$%! There's an asteroid at 12:00" times. You can't expect to cruise through space and not come across some floating debris, can you?
Not quite. It is in fact the kinetic energy of the plasma that is being transferred to the spacecraft; the electrical interaction is just the transfer mechanism. So, yes, the space station will be pushed back in a fashion more or less prescribed by Newton's 3rd Law. However, as mentioned above, the acceleration produced by the conservation of momentum is proportional to the mass, so if the space station is massive enough, this won't be a problem. Plus, I'm sure some corrective measures can be taken with orbits to minimize the effect.
To follow knowledge like a sinking star, / Beyond the utmost bound of human thought. ("Ulysses", Tennyson)
Google news search for "mag-beam" returned http://www.newswise.com/articles/view/507649/ and http://www.universetoday.com/am/publish/mag_beam_p ropulsion_system.html?14102004 with a sci-fi looking picture.
Froogle search for "mag-beam" did not match any products. :)
We've got a world full of nerds excited about spending months in a can to get to a world with no water and no air and no life that we know of, hoping to use the information gained on the trip to hop in another can to go to other worlds which will most likely have no air and no water.
Meanwhile, we're on a planet that our bodies have been custom built over billions of years to live on (with both air and water-perfection for us by definition) and we are so expectant at our own ability to screw the place up that we are trying to plan on the day when we'll have to leave this place because of what we've done to it.
Doesn't it seem a whole lot EASIER to just change our planet screwing habits than it does to attempt to terra-form a dry, red rock-which we would inevitably screw up in our same unlearned fashion?
This is a waste of money that would better be spent trying to figure out why we screw things up for the world around us so much better than we fix them. We have great success at helping our own species in specific fashions while screwing every other form of life up in general. Our myopic vision does not allow us to see big pictures, those that are more than 2 steps away from any cause or cure we undertake.
Any other planet with life on it out there would undoubtedly regard us as the trailer-trash that devalues the neighborhood. "Welcome!" signs are not in our future...
This reminds me of an idea from Larry Niven's Known Space stories. He thought that intrasystem transport would go through a phase in which photo-sail craft would receive an additional push from orbiting lasers sitting where they have access to high-density power supplies, making the light and simple vehicles fast enough to be practical for routine use.
:-)
:-/
(This plan figured interestingly in the first Man-Kzin War. Kzinti planners had not used reaction drives in so long that they failed to realize what a fleet of exawatt laser stations scattered all over a star system could do to an incoming force.
Come to think of it, long-range focused plasma beams could have military uses, even if they aren't dense enough to instantly zap the other guy out of existence. So, funding should be assured.
Otherwise there won't be any slowing down at Mars , just a big splat. Unless the ship carries conventional thrusters too of course, but the fuel required to slow down would be immense and then we're back to square one.
Because we all know that the steam engine, the universal governor, the printing press, the cotton gin, the combine, the internal combustion engine, the Model T, the airplane, the transistor, the integrated circuit, the telephone, the chemical battery, the capacitor, the steam tubine, the incadescent light, the phonograph, the film projector, the Compact Disk, and the mechanical loom are all examples of not much happening in the world because of the guiding principle of life being profit.
You can tell a great deal about the character of a man by observing those who hate him.
Does that picture remind anybody else of the sail ship that they used in the movie Tron? Were they ahead of the game -again-?
It'll be a long time until any of the (former) X Prize teams get anything into orbit, and when they do it won't be very similar to the purpose-built vehicles they've been working on up until now.
You're forgetting that Scaled Composites (Burt Rutan's company) was heavily involved with both the McDonnell-Douglas Delta Clipper and Lockheed Martin Venture Star programs. Though these programs were not complete successes, it does mean Scaled Composites has actual experience in building real spacecraft and that means Rutan has a pretty good idea of the engineering needed to build a spacecraft to reach low Earth orbit (LEO) at reasonable cost.
Imagine when 80 days around the world was an extraordinary and unbelievable accomplishment, now it seems that something as odd as 80 days around the solar system may be laughed at in a 100 years time.
In todays world, I cannot imagine how restrictive travel must have been, in tomorrows, they will pity us with our cars and segways!
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
Just a few nits - the Space Shuttle Main Engine has an Isp of ~430, and still throws away a lot of stuff! Most Hydrogen/Oxygen engines have Isp in the 400 range, while the 300 range is typically hydrocarbon such as kerosene. I would have difficulty believing that a 200 Isp engine would make it to orbit, if it hadn't already been done. (Pretty amazing engineering, that!) The mass ratio required goes up exponentially with Isp, and at 200 it is ~90:1 (so for every kg in orbit, you launched with 90 kg!).
As for your other comment, about how high Isp devices seem to always have low thrust, that is because to a first approximation we are limited by the power available. Engine power is proportional to thrust x Isp, so assuming the same power source increasing Isp decreases thrust. Going from a dense power source (chemical fuel) to a non-dense power source (solar panels) only makes that worse!
while (sig==sig) sig=!sig;
I'm not going to analyze every single item on your list...
But the Printing Press? Did you think this through? Do you really think Johann Gutenberg's motivation was profit??? Have you ever read Henry Ford's writings on business organization? He was a far more ardent critic of international finance than me.
I think you need to read a little more about the people who invented the items you are discussing. Most were invented by men who followed their dreams and were hardly concerned with financial gains. More importantly, financial concerns did not dictate whether or IF they pursued that dream.
I don't read or respond to AC posts
Have you ever read Henry Ford's writings on business organization? He was a far more ardent critic of international finance than me.
From what I know of Ford, I can only assume that "international finance" is a code-word for "The Jews".
--grendel drago
Laws do not persuade just because they threaten. --Seneca
As I understand it, VASIMR and other plasma based systems require megawatts of power. I wonder where they are going to find a dense energy source that can provide that much power. Consider that the space shuttle only requires power on the magnitude of kilowatts. It would be interesting to see a nuclear powered (think submarine, not actomic bomb) spacecraft because that might be the best way we can put a dense enough energy supply on a craft.
Of course you need some kind of shielding, this is space after all. But your velocity has little to do with the danger of the debris that you will encounter. Speed is relative. Chances are that the debris that impacts your ship will be moving at 200,000mph. Even if you are motionless, you have the same type of impact. All space debris is not just sitting out there motionless waiting for some ship to fly into it.
True enough, but the likelyhood that you will encounter some form of debris increases with the distance that you travel. Sit in one spot, not a big deal. We know where a lot of that is and where it's going. Go rocketing around the solar system, Whoo-boy!
The problem with using a celestial body's magnetic field as a force is that in many cases, the field is far too weak or nonexistent. The moon and Mars lack magnetic fields, for instance, and the earth has a magnetic field of about 0.5 gauss. In comparison, powerful magnets used in NMR generally are in the 10-20 Tesla range (100,000-200,000 gauss). Which is to say, the earth's magnetic field is great for turning compass needles and deflecting the solar wind, but not nearly strong enough to repel magnets at reasonable velocities. The overall energy of the earth's magnetic field is of course enormous- we're talking about 100 billion billion tons of iron acting as a dynamo, but the field strength- perhaps better called the flux density is not very high- lines of magnetic force are spaced too far apart. Despite being many orders of magnitude weaker in terms of absolute force strength, gravity predominates over electromagnetism as the major force we encounter from a planet. The problem is that almost every object in the universe that produces a gigantic magnetic field is also extraordinarily massive, so that the attractive force of gravity competes with the magnetic field- and dipole magnetic field strength falls off as the third power of distance versus gravity, which follows an inverse square law.
Your idea might actually work around a neutron star, which can produce a field in the 100,000,000 Tesla range, which might be enough to escape the immense gravity. You probably would not be able to survive this, however.
Also, while such a design would not use an fuel in the manner that a rocket would, you would need to expend energy to create the very powerful field required. Frankly, given the requirements of the scenario, which demand an object with very strong magnetic field and a ship that can produce a very strong magnetic field, there are better options. If you have an object like the sun putting out a solar wind, solar sails are a possibility. If you have an enormous electromagnet at your disposal, well, an idea like the one the story proposes, an ion drive of some sort, a railgun system- lots of options.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
All you have to do is reroute power from the phaser bank to the deflector array.
http://www.ess.washington.edu/Space/magbeam/
The station is propelled backwards a small amount due to the KINETIC energy it imparts to the plasma beam, but that level of energy is INSIGNIFICANT. The station also imparts MAGNETIC energy to the plasma beam, but that does not propel the station backwards at all.
The ship is propelled forwards primarily due to the MAGNETIC energy in the plasma beam, not the KINETIC energy. It does this by creating an electromagnetic shield that repels all magnetically charged particles. This force is much stronger than the KINETIC energy.
Newton's 2nd law is preserved. The shield pushes the magnetized plasma particles away with enough force to accelerate the ship to high speed. Turn the shield off, and it won't go very far.
And anyone who thinks this plasma beam could scorch the Earth doesn't realize just how much energy the Sun blasts the Earth with constantly. The Earth has its own magnetic shield, and what little of the solar wind does get in is scattered in the upper atmosphere (i.e. auroras). Even though it's a more focused beam, the beam would be spread thin before it came close to the ground.
The biggest problem with this method is not being able to slow down if there's a problem at the other end. Even if there's not a problem at the other end, it would be like trying to throw a rock from here to Mars and expecting to hit a very small target precisely when it got there. Without course corrections on the way, it will miss by hundreds of miles. Even with corrections, it will very likely miss on the scale of hundreds of yards.
IMHO, they should use this only for acceleration. Add ion thrusters to the craft, and it can help accelerate the craft as well as decelerate it as it approaches Mars (making continuous course corrections if necessary). The last step would be a gravity-assisted deceleration to put the craft in orbit. It can meet up with the mag-beam station later, which will help to send it back to Earth quickly.
The ion thrusters would also be insurance against the station on the other side breaking down. It may take a few extra months to get home, but ion thrusters can provide continuous acceleration for years. You could put extra rations in the station itself. If and when it breaks down, the rations can be transferred to the ship for the longer ride home. If it doesn't break down, then the ship remains lighter and will be easier to send home.
NASA has this page explaining the physics and why it granted the money to the UWash research team. And the NASA page responds...The UWASH page pointed to by the article is somewhere behind a cloud of smoke coming out of their poor slashdotted server. 350 comments later, I still cant raise it.
SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
I'm an engineer.
If you put me in charge of a Mars mission here's the only proper way to do it.
#1 what we did in the sixties, whistle stop one pass visits, are pointless, if you're going to go then go, don't fuck around.
#2 we have the perfect platform for solar system operations right on uor doorstep, Luna, that and the L1 and L2 largrange points in lunar orbit for stuff that the moon's 1/6th gravity will make difficult or expensive.
#3 all space vehicles will need enough delta vee to decelerate to matching velocity with the target, whether that target is Mars, another planet, or an asteroid, that's no big deal we can use MHD which will efficiently generate low braking thrust for long periods.
#4 all space vehicles and this includes "materiel" of any kind, including "lego" style construction sets and so on, can be given practically any velocity you like by launching from a lunar linear accelerator, these work REALLY well in a vacuum.
SO top priority will be getting mebbe 500,000 tons of mass up to the moon to buind a nearly self sufficient base.
Best way to do that is a two pronged approach.
1/ Develop REALLY heavy lifters, nuclear salt water is cool as a starting point, first step need to be throw everything at perfecting Fusion until it's as doable as fission power plants.
2/ Develop (materials) for the space elevator.
The united states spends 450 BILLION dollars every year on the military, if that lot was thrown at this project you could adopt a JFK / Apollo sort of timescale and we'd have a viable and working moonbase by 2020 AD easy.
If the USA doesn't do this, there will be a moonbase by 2050 at the latest, and it will be Chinese.
When that happens the entire might of every military on the planet, IN CONJUNCTION, will be as effective as wet toilet paper agauinst a
Who knows, I may even live long enough to see it.
http://slashdot.org/~GuyFawkes/journal
I saw a talk, by this group, when they ventured across the state to my University. Despite the fact that all researchers are convinced that their new way of doing something is so much better than the other ways, this group really seems pragmatic about the whole thing.
They admit that the difficulties in getting this to work are tremendous. But from a cost standpoint (as opposed to nuclear methods, the only other energy source we can work with right now that provides enough energy density -- antimatter has a much higher energy density, of course, but we haven't any way of carrying it with us!), the UW method is the best I've seen so far, and it doesn't really screw around with the tricky issues of getting a nuclear source up in the atmosphere, where a problem can cause BIG problems for those of us on the ground. His charts showed that among all the methods out there (including some -- I don't remember seeing some of the parent poster's suggestions -- of Orion, Nuclear Salt Water, etc.), this dealie from his group sort of lies on a critical line between expense, availability, and ability to develop it to a useful stage.
Technical, very tricky engineering is required to get their "induction coil" out there, and have it be strong enough, but once it's deployed, the basic physics behind the thing is really pretty foolproof (as far as I can see).
I *did* ask him during the colloquium whether the accelerations provided would be enough for a long manned spaceflight -- they're SO much less than 1g. He said that for (far-in-the-) future flights, they have found a way to couple the fields' angular momentum to the "sail", thus spinning the spacecraft about the axis of translation, so that you could essentially have a spinning ring of which sci-fi writers are so fond. However, the efficiency of this is pretty low, so to spin the thing up, you might want to use chemical rockets, and let the plasma thingy do its job in the other direction.
Correct me if I happen to be mistaken, but what physics and maths I attended state that the greek Delta translates in equations as the phrase "change in".
So, therefore, Delta-V = change in V (or change in Velocity).
If, "Delta-V for rockets is all about the final velocity obtained".
Why is the symbol Delta used instead of one for maximum?
"Secrecy is the keystone of all tyranny. Not force, but secrecy
So here's an idea. Put a captured asteroid into an elliptical orbit. Perigee is at about 200 miles, going about 10 km/sec, apogee is at about 18000 miles going about 1900 km/sec. As the asteroid approaches perigee, it lowers a cable (made of space-elevator rope) into the upper atmosphere. As the cable gets into the atmosphere, the asteroid starts paying it out very fast, so that the end moves slow enough to be grabbed by a high-altitude airplane and attached to a spaceship. Once attached, the asteroid pays out cable slower and slower, accelerating the spaceship to the asteroid's velocity, and very slightly slowing the asteroid in its orbit. Eventually the asteroid starts reeling in the cable faster and faster, accelerating the spaceship further.
The spaceship only needs to be accelerated a little past the asteroid's velocity to reach escape velocity. There are a few possible ways to correct the energy loss of the asteroid's orbit. The simplest is for the airplane to attach a fuel tank to the cable along with the spaceship so that after the spaceship detaches, the asteroid can reel in the fuel and do a burn to pump its orbit back up.
Of course there's a big PR battle to be fought, to make people feel good about a big rock in a relatively low orbit over the earth. But if it worked, it would use a lot less rope than the space elevator, and it would get you into space quicker.
WWJD for a Klondike Bar?
Yeah, I remember when that asshole Skylab used to post on slashdot- posts filled with drivel and racial attacks. Let this be a warning to everyone on slashdot- trolling & flamebait posts can kill your karma, and this bad karma can follow you offline as well.
You've been warned...
Then say that and dont be sarcastic.
:-)
I agree we need to slow human growth and otherwise learn to me more efficient with the earth we have.
I dont see how that means that space, both near and far will not be *part of* a solution to overcrowding.
I dont agree that we will run out of land and resources before we can send *some* people off to space colonies. At least not if we *begin* sometime soon. If we wait, then yes, we may run out.
Also, there are other benefits to having a human population in space.
A: Catastrophies happening to earth dont wipe out the human race. ( debate on wiping out the human race being a good thing can begin now
B: All the manufacturing that is so polluting here on earth need not be so in space. Not to mention the raw materials that would be available to us without having to damage the earth.
I would guess there are other benefits I am not seeing right now.
So, in my opinion, the solution is
here on the ground,
in near space,
in deep space.
All of the above.
emt 377 emt 4
Having been corrected on this, I often feel a need to pass it on.
The moon is:
just over 1/4th of earth's diameter (27%)
roughly 1/6th of earth's gravity, (17%)
roughly 1/81st of earth's mass (1.2%).
roughly 3/5th of earth's density.
The mass part is one of the highest in the solar system, but I believe that Pluto/Charon have us beat by a comfortable margin. Of course, a lot of people want to have Pluto rescheduled as something besides a planet, but that's an argument for another thread.
Wake up - the future is arriving faster than you think.
I've gotten curious enough about this stuff that I've started learning a little bit about orbital mechanics. I've written some Python code to do the calculations for this stuff. Here's the asteroid's orbit:
This needs my libraries for physical units and orbits, and produces these results:WWJD for a Klondike Bar?
I am ignorant of the forces used in this technology, but if I am correct...
You have a space plasma generator orbiting the sun that will push payloads into a Mars-intercepting trajectory. OK, fine and dandy.
Now, if it's shooting all this high energy plasma out one end, won't there be a reaction of its own in the opposite direction, effectively causing the force on the payload to be cut in half, while also shooting itslef way the heck out of the original "stationary" orbit? I'm sure someone smarter than me has already thought of this, I just can't see the solution.
> With an energy model (e.g. you must climb to height X and introduce "potential energy" Y--escape velocity is derived from a kinetic/potential energy model anyway), it becomes unambiguous about how energy you've spent so gains you, and you can now integrate issues of energy lost to drag from doing anything other than flying straight up, and the validity of shooting straight up is clear.
In theory, you're correct, but there are other factors with the "space plane" design that change the balance. The first is that using a space plane means you only need to lift a portion of your craft out of the atmosphere, leaving the plane part behind, so you need less fuel on the "space" part of the plane. Second, the "plane" part of the space plane can incorporate an air-breathing engine, so you don't have to carry all of the oxidizer with you from the launch pad, like the shuttle does. This lowers the amount of total weight you need to lift, which (using proper mission design) could offset the extra energy you're using in a not-straight-up flight. Whether the savings from less oxidizer/less to-space weight can make up for the extra wasted energy remains to be seen, but I have high hopes that it can be.
Virg
I must have missed something in the article. I seem to remember Newtonian mechanics requiring that any force have an equal and opposite force. So, if this beam is going to push a craft, something must push the beam. And, if the satellite is pushing the beam, then something must be pushing the satellite. Now, if the satellite is sitting out in space, what's pushing on it? Isn't the satellite just going to fly backward (at a rate dependent on the ratio of its mass to that of the craft)? What did I miss in the article?
For generating the plasma, Focus Fusion looks like a real possibility. Could even be light enough to carry onboard for power and backup propulsion.