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Plasma Propulsion Could Cut Time To Mars in Half
NEW ROCKET TECHNOLOGY COULD CUT MARS TRAVEL TIME
An agreement to collaborate on development of an advanced rocket technology that could cut in half the time required to reach Mars, opening the solar system to human exploration in the next decade, has been signed by NASA's Johnson Space Center, Houston, TX, and MSE Technology Applications Inc., Butte, MT.
The technology could reduce astronauts' total exposure to space radiation and lessen time spent in weightlessness, perhaps minimizing bone and muscle mass loss and circulatory changes.
Called the Variable Specific Impulse Magnetoplasma Rocket (VASIMR), the technology has been under development at Johnson's Advanced Space Propulsion Laboratory. The laboratory director is Franklin Chang-Diaz, a NASA astronaut who holds a doctorate in applied plasma physics and fusion technology from the Massachusetts Institute of Technology, Cambridge.
Chang-Diaz, who began working on the plasma rocket in 1979, said, "A precursor to fusion rockets, the VASIMR provides a power- rich, fast-propulsion architecture."
Plasma, sometimes called the fourth state of matter, is an ionized (or electrically charged) gas made up of atoms stripped of some of their electrons. Stars are made of plasma. It is gas heated to extreme temperatures, millions of degrees. No known material could withstand these temperatures. Fortunately, plasma is a good electrical conductor. This property allows it to be held, guided and accelerated by properly designed magnetic fields.
The VASIMR engine consists of three linked magnetic cells. The forward cell handles the main injection of propellant gas and its ionization. The central cell acts as an amplifier to further heat the plasma. The aft cell is a magnetic nozzle, which converts the energy of the fluid into directed flow.
Neutral gas, typically hydrogen, is injected at the forward cell and ionized. The resulting plasma is electromagnetically energized in the central cell by ion cyclotron resonance heating. In this process radio waves give their energy to the plasma, heating it in a manner similar to the way a microwave oven works.
After heating, the plasma is magnetically exhausted at the aft cell to provide modulated thrust. The aft cell is a magnetic nozzle, which converts the energy of the plasma into velocity of the jet exhaust, while protecting any nearby structure and ensuring efficient plasma detachment from the magnetic field.
A key to the technology is the capability to vary, or modulate, the plasma exhaust to maintain optimal propulsive efficiency. This feature is like an automobile's transmission which best uses the power of the engine, either for speed when driving on a level highway, or for torque over hilly terrain.
On a mission to Mars, such a rocket would continuously accelerate through the first half of its voyage, then reverse its attitude and slow down during the second half. The flight could take slightly over three months. A conventional chemical mission would take seven to eight months and involve long periods of unpowered drift en route.
There are also potential applications for the technology in the commercial sector. A variable-exhaust plasma rocket would provide an important operational flexibility in the positioning of satellites in Earth orbit.
Several new technologies are being developed for the concept, Chang-Diaz said. They include magnets that are super-conducting at space temperatures, compact power generation equipment, and compact and robust radio-frequency systems for plasma generation and heating.
Coordinated by Johnson's Office of Technology Transfer and Commercialization, the Space Act Agreement calls for a joint collaborative effort to develop advanced propulsion technologies, with no money exchanged between the two parties. Such agreements are part of NASA's continuing effort to transfer benefits of public research and development to the private sector.
before some idiot straps one to four wheels and tries to break mach 2 on the salt flats?
And better yet: How long after leaving the line before same fool disintegrates the car and is strewn over fifty square miles of ground?
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Even though this technology would cut the time to Mars in half you can bet that the kids would still spend the whole time whining.
"Are we there yet?"
Nasa's simply going to have to do better :).
Well, this is definitely a boost for the hopes of manned exploration of Mars, which means that this technology will almost certainly not be used to it's full potential.
It constantly astounds me that world governments, with all the obvious environmental problems, refuse to whole-heartedly endorse space programs. Certainly, the lack of participation of nations in the shape of Russia (although their space program is/was generally good) is understandable, but the U.S. and other prosperous countries need to take some leadership here.
An Internation Space Station is a good start, but the political infighting regarding the development of it is discouraging. We need governments to realize that, with 6 billion people on the earth, that we don't have the resources to maintain an acceptable standard of living infinitely.
Traveling to another planet to explore, in a precursor to either inhabitation or mining, would be an even better use of this technology. I for one hope that world governments wake up (and that waking up is continigent upon public sentiment) and realize that right now is the time to radically advance our exploration of space.
Scythe
Sure, in a race between the two the plasma rocket sounds like it would win--by a long shot.
But if I want to be on Mars ASAP, which technology is going to get me there first? Conventional, tried-and-true, already-exists rockets? Or untested, not-yet-mature, haven't-built-one-yet technology?
Just launch a damn ship NOW.
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Scientific American ran a really detailed article a few months back on Mars missions. It discussed several propulsion systems, including this plasma thingee.
Basically, is having a plasma rocket inherently more dangerous to be launching through the atmoshpere than the normal chemical rockets currenntly employed?
Lastly, I guess is the bit about "large magnets that are super-conductive in space temeperatures" imply that these rockets may not be able to leave orbit in order to keep the engine functional (or have massive amounts of cooling available to take over for atmoshperic descent).
--sugarman--
I wonder how bulky it is, I get the feeling it'll be big. Getting it into space would be expensive, perhaps manufacturing in orbit would be ideal.
:)
If its not too large, I'd like to propose making a plasma gun ala Doom and Q3a.
'Neutral gas, typically hydrogen' neutral meaning 'non-ionised' I suppose. At least it fits with Elite and the hydrogen fuel suggested there
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Rush down to your local blood center and donate some of your plasma!
count to ten
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You are thinking of Deep Space One, or whatever it was called.. NASA's deep space probe last year tha tused ion propulsion (different than plasma propulsion). Roughly similar in concept, but not nearly as violent. In fact, not violent at all.
And it wasn't that each particle gave thrust equal to the weight of a piece of paper, it was that the *total* thrust was that of a piece of paper...
the thing is, it's extremely efficient, and considering the length of it's journey..
--
Here's my mirror
Q: Is there a reason that the Martian landscape, a completely different planet, so strikingly resembles the Arizona desert? (you bet your butt there is)
Q: Why do liberals find it so decidedly convenient to distract schoolchildren with prophetic nonsense about "other planets" instead of focusing their attention on the here and now where it belongs? Lots of topics of education are being outright ignored in favor of liberal subjects such as astronomy, evolution, and heliocentrism.
Mike Roberto (roberto@soul.apk.net) -GAIM: MicroBerto
Berto
I would think it'd take more effort to establish a self-sustaining base on the Moon than it would on Mars, given the limited resources to be found on the Moon.
But, the advantage to the Moon is the proximity to Earth - if things go wrong, its just a 3 day trip to the plentiful resources of Earth.
So, we refine the self-sustaining tech needed to live on Mars, using our own backyard lab (the Moon), and once that's all happening, send the tech off to Mars. Not to mention that we could probably *manufacture* half of the Mars base from the Moon, which would be cheaper and less dangerous than doing it here on Earth. Heck, we could probably use all sorts of crazy ass tech on the moon to build things better, such as nuclear technology, etc.
Seems sorta backwards to me that we're ignoring this resource and trying to get straight to Mars instead, but then again I don't know how these things are budgeted. Perhaps there are political reasons for getting th Mars before doing the Moon thing - and after all, politics drive the space program.
; -- the corruption of government starts with its secrets. a truly free people keep no secrets. --
This is great and all but the most fundamental difference between this engine and a chemical rocket is that the energy source is electric instead of chemical, and that that energy has to come from somewhere.
It's interesting that in none of the press releases do they mention that any ship using this propulsion system would need to have a fair sized nuclear pile (likely more than Cassini's 76 pounds of plutonium) to generate the electricity needed.
Deep Space's ion drive, while having an incredible specific impulse, was pushing so little fuel at any given time that a moderate power source would work. If we're talking about driving 100 tons of cargo to Mars in a speed race however, it's going to require far, far more electricity than a solar cell could reasonably capture, and forget batteries. They can't store enough, even if they weren't damned heavy.
I'm not saying it's for better or worse, but the fact that this propulsion system would mean launching large amounts of plutonium atop a chemical rocket to get out of the Earth's gravity well shouldn't be overlooked or swept under the rug. The potential for disaster is there.
Kevin Fox
Kevin Fox
It's too bad that nothing much happened after the commendable Tom Hanks film, Apollo 13 , unlike Saving Private Ryan which helped get the ball rolling on the WW2 Memorial.
By all means, this is an issue to keep in mind during the coming election campaign. Simply ask the candidates where they stand on NASA funding, and let them paint themselves as either populist tax-cutters or visionary opportunists.
Stop by my site where I write about ERP systems & more
Here's some rough/bad math on the speed for the halfway point:
.025 x 10^6 km/h (or 25000 km/h or 15625 mph for those of you in the states) would be your average speed, making your top speed .050 x 10^6 km/h (or 50000 km/h or 31250 mph for the americanos).
;)
Take the distance between Earth and Mars, divided by the time to get there (v=d/s) for the average speed. Assuming 0 starting and ending speed, constant acceleration until the halfway point, and the same acceleration in the opposite direction afterwards, the top speed would probably be about twice the average speed.
Not knowing my astronomy, but looking at some stats, I'll take a rough stab and say the distance would be about 55 x 10^6 km (just for a round number).
So 3 months is 2160 hours.
So the acceleration would be about 12.9 m/s^2 or roughly 1.3 G.
Now, I'm sure I've miscalculated in there - and I'm not a rocket scientist (ha ha, funny joke) so I'm probably wrong... but 1.3G for continuous acceleration doesn't sound too bad. You'd come back stronger and shorter for the experience...
BlackNova Traders
To clarify this point for those who were too busy learing C++ in school to read any Einstein:
As an object with mass approaches the speed of light, the ammount of force required to accelerate approaches infinity.
Therefore the speed of light (represented as "c") is not only theoretically impossible for a passenger vehicle to reach, but before you even get up to that speed you will reach a point where more acceleration is Not Worth The Trouble.
On top of that, there are troublesome issues of time deceleration and lots of other hard math problems that lead one to desire a better way of getting from point A to distant point B than getting a rocket to go "really really fast". Some serious thought and lots of bad sci-fi has been applied to this problem, but so far with few promising conclusions.
Information wants to be anthropomorphized.
They've been containing the heat from hot plasma for some time now for one of the methods used for nuclear fusion. They do it in a torus (donut). I don't think that the plasma actually touches the side of the torus itself, but rather, is contained by the magnetic field.
Hmm, let's not.
Let's see, we can work on developing constant acceleration technology that makes travel time proportional to a logarithm of the distance, or we can keep screwing around with old burst acceleration technology (rockets) that makes time directly proportional to the distance.
Once we have the good constant acceleration engines, we could go anywhere we wanted in the solar system. The Pluto round trip takes only about 7 times as long as the Mars round trip (I assume simplified trajectories; real space travellers would use quicker ones). At a very reasonable 0.01 g, that means a month and a half for the Mars round, under a year for the Pluto round.
Or we could, as you say, just launch a damn ship NOW... and have another Apollo that leads nowhere. Woohoo! Another plastic flag and some footprints on a dead world for us to not visit for decades! That's something to get excited about, isn't it?
For constant accleration, zero initial speed:
d = (at^2)/2
t = sqrt(2d/a)
a = 2d/t^2
d = 2.8 x 10^10 m (halfway)
t = 45 days (halfway)
t = 45*24*60*60 s
t = 3.8 x 10^6 s
t^2 = 1.5 x 10^13 s^2
a = 2.8 x 10^10 m / 1.5 x 10^13 s^2
a = 0.004 m/s^2
or roughly 0.0004 g, with your assumptions.
At 1.3*g, it would take about two days.