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An artist's rendition of three plasma engines burning in space, propelling a spacecraft, perhaps to Mars.  (Source: Ad Astra Space Corporation)

The engine features a three cell design. The first cell creates plasma from hydrogen at 10,000 deg. C. The next cell heats the plasma with radio waves to approximately 100 million deg. C. The last cell is a nozzle which controls how fast this fuel is let out, protecting the spacecraft and allowing acceleration control.  (Source: Ad Astra Space Corporation)

A computer rendering of the engine module.  (Source: Ad Astra Space Corporation)

The actualized plasma rocket under development at the Johnson Space Center.  (Source: Ad Astra Space Corporation)
New Vasimir engine could cut Mars travel to 60-70 days, allow greater rocket fuel economy

DailyTech has covered advances in the field of rocket propulsion and spaceflight.  From such theoretical technologies as a laser engine, to actualized devices like ion drives, there are many unique ideas in the field, despite the relatively tight budgets.

The key challenge facing rocket designers is basic physics.  Propulsion is determined by two key factors -- how much stuff you throw out the back of the rocket (mass) and how fast that stuff is going (velocity).  One of these factors can be relatively low if the other is high to compensate.  Thus on one extreme you have the solid-fuel and liquid fuel rockets -- these exit burning chemicals at relatively low velocities (compared to alternative technologies), but they dump large quantities of mass and therefor produce sufficient thrust.  On the other extreme you have technologies such as ion drives, which exit a minuscule amount of mass at much higher speeds, to eventually produce a sufficient impulse.

The problem with solid/liquid fuel rockets is that they require massive fuel stockpiles, hence the big fuel tanks.  And while they produce enough thrust to reach orbit, their fuel is quickly exhausted.  Ion drives, on the other hand, can not reach space without using liquid rockets, so they can only activate after the fact.

However a new technology may soon leave both options in the dust.  The new tech is a plasma rocket engine developed by Texas based startup Ad Astra Rocket corporation.  The company was founded by former NASA astronaut Dr. Franklin Chang-Díaz, who serves as its chief executive.

The new rocket is named Variable Specific Impulse Magnetoplasma Rocket (VASIMR).  A traditional rocket can produce a specific impulse of around 450 seconds, or in other words 1 pound of thrust from 1 pound of fuel for 450 seconds.  VASIMR can produce several times this amount, cutting a trip to Mars from 6 to 9 months with conventional rockets down to a mere 2 to 3 months.  It could do this by being able to burn fuel continuously the whole trip accelerating on the first half of the journey to Mars and decelerating on the second leg of the journey, preparing to enter orbit.

The rocket consists of three critical units or cells.  The first is the plasma generator.  It sits deepest into the rocket and consists of a generator which ionizes heated light gases such as hydrogen, creating plasma -- atoms stripped of their electrons.  The plasma, at a modest temperature of 10,000 °C, is then pumped into the second unit, the amplifier.  In the amplifier cell the plasma is blasted with electromagnetic waves via radio waves.  These waves heat the plasma burning hot similar to how food is heated in a microwave.  Finally the ultra-hot plasma is channeled in magnetic containment fields to the final cell, the magnetic nozzle.  This nozzle is the critical control which controls how much fuel exits, and how fast the exiting plasma is going. 

The nozzle also protects the spacecraft from the burning hot plasma.  How hot is the plasma exactly??  Well, early estimates are that it will be around 180 million degrees Fahrenheit (100 million degrees Celsius), only about 25,000 times hotter than the burning gases exiting the space shuttle.  However, thanks to the magnetic nozzle the plasma can be tamed and channeled into useful impulse.

Dr. Chang-Diaz explains, "Rockets tend to work much better the hotter the exhaust is and the plasma allows you to go to temperatures millions of degrees rather than thousands of degrees in a conventional rocket engine."

In order to accomplish the critical control of the fuel, VASIMR utilizes superconductors to make pumped up magnets.  Explains Dr. Chang-Diaz, "To harness the plasma at those temperatures, the only way is…to have a very strong magnetic field to hold it together.  The only way to create those fields in a reasonable way in space is with superconductors."

His company, along with NASA, academic partners, and corporate partners developed special superconductors at the Johnson Space Center’s (JSC) Advanced Space Propulsion Laboratory to rise to the occasion.  These superconductors have a wide array of applications, but for now the focus is on the plasma engine.

So how close is the engine to deployment?  Well after years of hard work, the engine is virtually complete and ready for its first "field test" -- a deployment in space.  At the AirVenture show in Oshkosh on July 29, US space agency's administrator Michael Griffin announced to the press that  "we are at the end stages of agreeing a co-operative agreement for NASA to test the Vasimir engine on station".

While no timescale was given for the launch, the deal is expected to be signed soon.  NASA already signed a broader collaborative agreement with the firm in 2006.  The model used in the tests aboard the International Space Station would be a scale model.  Nonetheless, it would be critical to gaining final insight to prepare the engine for full deployment.

Plasma rockets are considered by many the best long-range propellant solution besides fusion rockets.  As fusion power is still a fledgling research field, plasma may help to fill the gap for many years to come.  Past fusion power, only exotic propulsion solutions could possibly yield greater speeds.

To view videos of VASIMR in action, please view the links on Ad Astra Rocket corporation's page visible here.


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errors
By slashbinslashbash on 8/11/2008 10:23:36 AM , Rating: 2
"Ion drives, on the other hand, can reach space without using liquid rockets, so they can only activate after the fact."

I think that should be "can't", not "can".

"It could do this by being able to burn fuel continuously the whole trip accelerating on the whole journey to Mars and decelerating on the return journey."

This makes no sense at all. If it did this, the ship would be at its highest velocity right as it passes by Mars. It would be like a 5-minute flyby at the cost of 3 months of travel. If you intend to stop at Mars and spend any time there, you have to accelerate for the first half the trip, then decelerate the last half of the trip.

Lastly, I can't believe that they intend to test it "on station." This is highly unproven technology. It needs to be in a separate satellite far away from anywhere that it can do any damage. And, unlike ion engines, it should be able to be tested on Earth, as presumably we would want to use this new form of propulsion to lift off from Earth (the most expensive part of space travel, fuel-wise).

Nit picking aside, this sounds like cool technology and I hope that it ends up working.




RE: errors
By Lonyo on 8/11/2008 10:37:18 AM , Rating: 2
Go to Mars -> release a pod containing whatever you are sending to Mars -> return back to Earth so the rocket can be re-used to send something else.
The vehicle which gets you to Mars doesn't necessarily need to stay there, it can just drop off its cargo (I would assume).


RE: errors
By slashbinslashbash on 8/11/2008 11:11:21 AM , Rating: 1
In such a case, the cargo would slam into Mars at v_max unless it had some way to decelerate. Such a deceleration would mean that the cargo would have to detach from the main ship long before they actually reached Mars. In which case, there wouldn't be any point in having the main ship at all.


RE: errors
By masher2 (blog) on 8/11/2008 11:21:28 AM , Rating: 2
> "In such a case, the cargo would slam into Mars at v_max unless it had some way to decelerate..."

Gravity slingshot + aerobraking.


RE: errors
By marsbound2024 on 8/11/2008 1:10:21 PM , Rating: 4
Gravity slingshots usually end up accelerating the spacecraft into a new direction, not slow it down. And as far as aerobraking goes, unless the probe uses a Hohmann transfer orbit and decelerates sufficiently to be captured by the Martian gravity, the probe will most likely either burn up in the Martian atmosphere, tear itself apart or speed off into space.

A good way to understand this is to read this section of the Hohmann transfer orbit article on Wikipedia:
http://en.wikipedia.org/wiki/Hohmann_transfer_orbi...

If the link ends up not working for someone, just wikipedia "Hohmann transfer orbit" and scroll down to "Application to interplanetary travel."

I am thinking that the fuel carried would be enough to allow the spacecraft to slow itself to sufficient velocity so that Mars' gravity can capture it and its atmosphere can continue slowing the probe down without risking damage.

If you want to know the effects of miscalculated aerobraking, just read up on the late (can I apply that term to something non-human?) Mars Global Surveyor and its bent solar panel that occurred during its aerobraking maneuver.


RE: errors
By Carter642 on 8/11/2008 1:41:28 PM , Rating: 2
Actually the spacecraft would reach v-max at roughly the halfway point of it's journey and then flip over and start decelerating to the appropriate velocity for orbital insertion. Remember BOTH gaining and losing velocity are products of acceleration.

With conventional rockets we simply can't carry enough fuel to accelerate the whole way to mars so we accelerate for a bit and then coast most of the way before braking at the end. With this plasma rocket we can accelerate more slowly but for a much greater period of time. Depending on the thrust, astronauts might even have appreciable micro-gravity on the way to mars which could help with all sorts of health issues. Exciting stuff for sure!


RE: errors
By masher2 (blog) on 8/11/2008 1:58:46 PM , Rating: 1
> "Gravity slingshots usually end up accelerating the spacecraft into a new direction, not slow it down"

A slingshot can speed or slow a spacecraft, depending on whether it enters the maneuver opposing or following the body's direction of motion.

> "as far as aerobraking goes, unless the probe uses a Hohmann transfer orbit and decelerates sufficiently to be captured by the Martian gravity..."

There's no deceleration needed for a Hohmann transfer. And as far as aerobraking goes, there isn't even a strict requirement that the velocity be low enough first to allow orbital capture...though it admittedly makes it easier from a practical standpoint.


RE: errors
By marsbound2024 on 8/11/2008 2:36:09 PM , Rating: 2
"Hohmann transfer orbits also work to bring a spacecraft from a higher orbit into a lower one – in this case, the spacecraft's engine is fired in the opposite direction to its current path, decelerating the spacecraft and causing it to drop into the lower-energy elliptical transfer orbit. The engine is then fired again in the lower orbit to decelerate the spacecraft into a circular orbit." - wikipedia the Hohmann transfer orbit

How do you propose in allowing Mars to capture the probe without some sort of deceleration? The gravity slingshot (following the path of motion of the body) alone would not be enough at sufficient velocities. Aerobraking also would not be enough because, as I mentioned before, the atmosphere would not provide enough pressure unless the probe entered deep enough and thus risked damage or loss. The probe will simply go into a heliocentric orbit as it passes Mars. Thus, maintaining the max velocity would simply create a flyby of Mars. Of course, if you want to completely make the use of the Vasimir completely irrelevant, then you can make a ridiculously long Hohmann transfer so that the spacecraft's outward velocity from the Sun causes it to decelerate sufficiently. But of course, the spacecraft will then have taken months to get to, thereby making the entire concept moot.


RE: errors
By masher2 (blog) on 8/11/2008 3:34:05 PM , Rating: 2
> "How do you propose in allowing Mars to capture the probe without some sort of deceleration? The gravity slingshot ...would not be enough."

You have to remember that a direct boost transfer to Mars that might be 3 times faster doesn't have a velocity that's 3 times higher. The path is much shorter, since the craft doesn't have to follow the circuitous Hohmann ellipse. So the velocity that must be shed isn't neccesarily that much higher.

As for aerobraking, even with current technology, we use it to shed the space shuttle's 14 km/s or so of dV from a GEO mission. A gravity assist can provide another couple km/s or so. Is that enough? I can't say without the actual mission parameters...but there's no theoretical limit on how much aerobraking can provide, given future advances in heat-shielding material.

> " in this case, the spacecraft's engine is fired in the opposite direction to its current path, decelerating the spacecraft..."

If you read the entry carefully, you see that the final deceleration isn't part of the Hohmann trajectory, but is merely used to convert the final orbit to circular. The point is that, beyond the initial impulse, a Hohmann transfer requires no additional deceleration or acceleration; it arrives at its destination already in an elliptical orbit.


RE: errors
By masher2 (blog) on 8/11/2008 10:46:29 AM , Rating: 4
> "unlike ion engines, it should be able to be tested on Earth, as presumably we would want to use this new form of propulsion to lift off from Earth "

The engine doesn't generate nearly enough thrust for a liftoff from earth; it's useful strictly in space. Also, it (and ion engines, for that matter) are tested here on Earth. They're just not "field" tested.

> "It needs to be in a separate satellite far away from anywhere that it can do any damage..."

There isn't a lot of energy in a plasma, even one at 100 million degrees. Take the old example of a hot oven...you can stick your hand into the 450-degree air of an oven without harm, but water at a mere 200 degrees will scald you instantly.


RE: errors
By phattyboombatty on 8/11/2008 1:05:07 PM , Rating: 3
quote:
The engine doesn't generate nearly enough thrust for a liftoff from earth; it's useful strictly in space.


I'm not disagreeing with you, but the article implies that the plasma engine could lift off from earth by distinguishing the plasma engine from ion engines by indicating that ion engines are only useful once they are in space.


RE: errors
By masher2 (blog) on 8/11/2008 2:03:06 PM , Rating: 2
I should have been more precise. The VASIMR technology itself is theoretically capable of thrust-to-weight ratios high enough to allow an Earth launch. That's a more advanced design however; the specific proposal for a Mars mission, though, would be an engine tuned for a lower thrust and operated only in space.


RE: errors
By EricMartello on 8/11/2008 3:39:26 PM , Rating: 2
quote:
There isn't a lot of energy in a plasma, even one at 100 million degrees. Take the old example of a hot oven...you can stick your hand into the 450-degree air of an oven without harm, but water at a mere 200 degrees will scald you instantly.


Sounds more like convection vs conduction...if you stick your hand in water, you are making direct contact with the liquid thus allowing for efficient heat transfer...vs air, where heat is transferred mainly by radiation which is less direct because it disperses into the atmosphere. The quantity of heat energy would be the same in both instances, but the water is more efficient at transferring heat to your hand.

What weighs more - a pound of air or a pound of water? :)


RE: errors
By albundy2 on 8/12/08, Rating: 0
RE: errors
By SilthDraeth on 8/12/2008 9:38:01 AM , Rating: 2
You are trying to be to smart. He meant a pound of each.

Back in Jr. High and other places a popular question was... "What weighs more, a pound of feathers, or a pound of bricks?"

To find out what kids where paying attention. So you obviously know the difference, but failed to catch the reason for his question.


RE: errors
By albundy2 on 8/12/2008 9:25:44 PM , Rating: 2
oh no i got it... don't know why i got downrated, but whatever.


RE: errors
By JustTom on 8/11/2008 11:18:56 AM , Rating: 2
quote:
"It could do this by being able to burn fuel continuously the whole trip accelerating on the whole journey to Mars and decelerating on the return journey."


I think what was meant is the craft would accelerate till the halfway point then decelerate the rest of the trip.


RE: errors
By JasonMick (blog) on 8/11/2008 11:38:54 AM , Rating: 2
quote:
This makes no sense at all. If it did this, the ship would be at its highest velocity right as it passes by Mars. It would be like a 5-minute flyby at the cost of 3 months of travel. If you intend to stop at Mars and spend any time there, you have to accelerate for the first half the trip, then decelerate the last half of the trip.


It could work either way. Either you could accelerate on the trip to Mars, slingshot, dropping a pod, and decelerate on the return, or you could accelerate to halfway, brake, then repeat on the return trip.

The important point is that the rocket could likely carry enough fuel to continuously burn during the entire transit.

quote:
Lastly, I can't believe that they intend to test it "on station." This is highly unproven technology. It needs to be in a separate satellite far away from anywhere that it can do any damage.


It is indeed likely to be tested at the ISS, according to NASA. As to whether it will be tested "indoors" or outside the space station, or how it will be tested, that has not been announced and is open to conjecture. However they test it, I'm surely they'll devise a workable plan to ensure safety of the station.

PS. For those interested, the news of the VASIMR engine has been around for a while. The major development is that its finally built and is close to being tested aboard the ISS.


RE: errors
By Carter642 on 8/11/2008 3:26:13 PM , Rating: 2
This thing really isn't likely to damage the station in any way. The thrust generated is much smaller than the stationkeeping thrusters they use already. The amount of plasma in the rocket at any given time is so small that it would only vaporize a couple of molocule's thickness off the inner wall of the rocket should the containment fail not to mention that the fuel is inert so there's nothing to explode. The only risks would be from the superconducting magnets quenching which would only really result in damage to the magnets and their cooling system.


RE: errors
By 16nm on 8/11/2008 8:47:43 PM , Rating: 2
Yes, not to nit pick, but a small comma can change everything... Highschool English teaches us that this is a sentence fragment.

quote:
However a new technology may soon leave both options in the dust.


"However, a new technology may soon leave both options in the dust."

or

"However a new technology may soon leave both options in the dust, [finish thought]."


RE: errors
By mmcdonalataocdotgov on 8/13/2008 8:00:03 AM , Rating: 2
When the ship is accelerating, it is burning fuel. When the ship is decelerating, it is burning fuel. Thus it burns fuel "continuously the whole trip."


100 Million degrees celcius?
By Schrag4 on 8/11/2008 10:08:01 AM , Rating: 3
Am I the only one that checked the calendar to make sure it's not April 1st after reading this? Can this even be tested/proven on Earth? I mean, how long does it take to cool plasma from 100,000,000 degrees celcius to room temparature? If we can really get something THAT hot, shouldn't we be using it to create steam? (Oh wait, I think I remember a DT article about plasma for power genration a few months ago)

Suddenly the plasma gun from Doom seems like a good idea!




RE: 100 Million degrees celcius?
By FaceMaster on 8/11/2008 10:18:50 AM , Rating: 5
What's a couple of 0's between friends?


RE: 100 Million degrees celcius?
By DEVGRU on 8/11/2008 10:37:55 AM , Rating: 3
"Finally the ultra-hot plasma is channeled in magnetic containment fields to the final cell, the magnetic nozzle."

Finally. Magnetic Containment Fields FTW! I'm no trekkie, but I think James Doohan would be proud. I can't wait to see the prototype fire up for the first time.


RE: 100 Million degrees celcius?
By frobizzle on 8/11/2008 3:33:19 PM , Rating: 2
quote:
However, thanks to the magnetic nozzle the plasma can be tamed and channeled into useful impulse.

Ahh..Impulse engines! I get it!!! Can't wait till the warp field generators are invented!


By geddarkstorm on 8/13/2008 2:05:43 PM , Rating: 2
There's some ideas out there at least :)

http://en.wikipedia.org/wiki/Alcubierre_metric


RE: 100 Million degrees celcius?
By lightfoot on 8/11/2008 11:54:35 AM , Rating: 3
Two flaws with your thinking - the plasma can't be used to generate power because it takes power to generate the plasma.

Secondly, even if the plasma could be created for "free" the mass of the hydrogen plasma is so little and its specific heat capacity so low that even with its extreme temperature it could not boil an appreciable amount of water.


By ImSpartacus on 8/11/2008 1:35:31 PM , Rating: 2
Yeah, when people hear Plasma, they go, "OMG it's ultra uber hot dude!"

Yes it is hot, but it cools so fast because they is next to no mass involved.

Plasma isn't special either, go look up the grape plasma experiment for your microwave on Youtube. I'm pretty sure all u do is cut a grape in half (leaving a scrape of skin still attached) and microwave it. It just looks like lightning (which also is plasma).


The real advantage...
By Shadowself on 8/11/2008 12:22:54 PM , Rating: 2
is the variable nature of the engine. It has the ability to throw out a relatively large mass of propellant per second at moderate Isp (<1,000 seconds) in one extreme of operation and throw out a small mass of propellant at relatively high Isp (> 2,000 seconds) in the other extreme. It also should have the ability it nearly continuously vary between the two extremes.

One issue with very high efficiency propulsion engines is that they are *extremely* low thrust. The highest efficiency ones (those with very high Isp [sometimes > 5,000 seconds]) is that the thrust is measured in very small fractions of pounds-force thrust per engine. Some of these engines could not even lift themselves off the surface of the moon, never mind the Earth (let alone propellant tanks and power sources -- not even considering a useful payload).

Another related issue to this is the gravity well of planets. In low Earth orbit, deep in the gravity well, ion propulsion engines lose their efficiency because they must thrust over long periods of time to achieve and appreciable change in satellite velocity. In low Earth orbit the most efficient changes in velocity are nearly instantaneous impulses. Thrusting over hours or days severely cuts into the native efficiency (higher Isp) of ion/hall/magneto-dynamic thrusters.

Thus a thruster that can have moderate Isp but moderate thrust in low Earth orbit that can then vary to relatively high Isp with low thrust as it gets to higher orbit or inter planetary space is a very useful thing.

One thing we do need to note is that for interplanetary space these still don't reach the efficiency of very high Isp engines. The figures I've read is that the current designs top out in the 1,500 to 2,000 second range. Very good, but not great for interplanetary while other engines can get to 5,000+ seconds.

Another thing to remember is the necessity for superconducting magnets in order to make this reasonably light enough. Active cryo-coolers and heat exchangers to dump the heat into space to keep these cold will add significant mass for long duration use (say a year for a Earth-Mars transit, then Mars orbit, then Mars-Earth transit, then finally Earth orbit).

Finally, yet another thing to remember is that these take massive amounts of electrical power. With current solar array technologies a reasonably sized one of these would require total solar array areas the size of a football field or larger (remember the solar flux at Mars is about half of what it is at Earth). This may mean using nuclear reactor(s) to power these engines -- which is an issue in and of itself!




RE: The real advantage...
By Master Kenobi (blog) on 8/11/2008 1:15:32 PM , Rating: 2
I see no problem sticking a small nuclear reactor on board. Infact this could be the first step to creating an interplanetary ship. Nuclear reactor, some large plasma engines, put it in orbit and away we go. Continual trips between Mars and Earth. Excellent!


RE: The real advantage...
By marsbound2024 on 8/11/2008 1:20:40 PM , Rating: 2
You might be interested in Project Orion or Project Daedalus and et cetera. I believe Project Orion had a goal of "Saturn by 1980" or something like that. These ships would be able to achieve 10% the speed of light, even more, all with current technology.


RE: The real advantage...
By masher2 (blog) on 8/11/2008 2:09:53 PM , Rating: 2
> "These ships would be able to achieve 10% the speed of light, even more, all with current technology"

Not with current technology. Daedalus presupposed inertial containment fusion, something we haven't quite mastered yet.

Orion could be built with current technology (or even 1960s-era tech) but it would be momemtum-limited to well under 5% of lightspeed.


RE: The real advantage...
By marsbound2024 on 8/11/2008 2:17:33 PM , Rating: 2
Using thermonuclear propulsion it could get up to 10% the speed of light, but nuclear fission would be something as you have indicated. So in a way, it really depends if you want to use fission bombs or hydrogen bombs.


RE: The real advantage...
By masher2 (blog) on 8/11/2008 3:06:00 PM , Rating: 2
The problem is that current large fusion bombs in the 1-10MT+ range are too large for an Orion-type "bang-bang" approach, and smaller-yield ones still generate a substantial amount of their energy from fission.


RE: The real advantage...
By masher2 (blog) on 8/11/2008 1:50:06 PM , Rating: 1
> "In low Earth orbit, deep in the gravity well, ion propulsion engines lose their efficiency because they must thrust over long periods of time...Thrusting over hours or days severely cuts into the native efficiency"

That's not strictly true. A low-thrust engine doesn't need to lose efficiency while orbiting in a gravity well. If the thuust angle can be kept tangent to the gravitational vector, there is no loss in efficiency. It's just a bit difficult to keep a spacecraft continually rotating as it follows its orbital path so it doesn't wind up thrusting against gravity.


RE: The real advantage...
By Shadowself on 8/11/2008 5:56:27 PM , Rating: 2
Actually it is true. Do the calculations for an impulsive transfer (e.g., a Hohmann transfer) and a continuous, extremely low thrust transfer, and you will see the difference -- even if you assume the thrust axis is normal to the maximum gravity gradient and even if you use an approximation of an extremely large number of conic sections instead of a nearly infinite spiral. It may not be intuitive, but it is so.

Also, continuously rotating the spacecraft is not difficult. Any realistic combination of reaction wheels, torque rods and reaction control thrusters can do it.


RE: The real advantage...
By masher2 (blog) on 8/11/2008 6:41:01 PM , Rating: 2
Again, not quite. I've done the calculations before, though it's been quite a few years since my college days. There are two effects going on here. The first is gravitional losses, and these only occur when your thrust vector has a nonzero component aligned with the gravitional vector. This is why the space shuttle and other launch systems quickly migrate from a vertical to a near-horizontal thrust arc soon after launch.

The second effect is the Oberth effect, but even this isn't a loss in efficiency for low-thrust engines, its a increase in efficiency for burns conducted within a gravity well, if the final destination is at a higher point in that well. The Oberth effect doesn't apply for orbital changes that don't increase the gravitional potential energy (such as out-of-plane changes). For changes that result in a lower orbit, the Oberth Effect means a low-thrust engine will be *more* efficient than a high-thrust burn.

And even for changes which result in a higher orbit, a low-thrust engine can take advantage of the Oberth Effect, if it can afford an extremly elliptical orbit and multiple passes.


NASA/US Gov't greatest fear
By Lord 666 on 8/11/2008 9:56:49 AM , Rating: 2
Private industry appyling technology to propel ahead (sorry for the pun) of themselves.

This would make same day trip to the moon or would it be like using a hammer to kill a fly?




By Alexstarfire on 8/11/2008 10:11:01 AM , Rating: 2
IDK, but I thought it would have taken longer to get to Mars than 6 to 9 months? Did they originally plan to just add boat loads of fuel to the rocket or what?

Either way, I only have one thing to say. ABOUT TIME.


RE: NASA/US Gov't greatest fear
By FITCamaro on 8/11/2008 11:00:36 AM , Rating: 2
Why would the government fear this? If anything they can use this to cut their own costs. And increase safety and reliability.


RE: NASA/US Gov't greatest fear
By Karmakaze on 8/11/2008 6:42:37 PM , Rating: 2
quote:
Why would the government fear this? If anything they can use this to cut their own costs. And increase safety and reliability.


Well, obviously they would fear this because in a libertarian utopia, government is nothing but a neutered cop, and all really useful stuff is done or made by mighty corporations for the benefit of mankind!

Of course, the fact that this engine would never have been thought of, let alone manufactured if it wasn't for the lucrative government funding that paid for it... Well that's just your authoritarian mindset kicking in, Commie!


By masher2 (blog) on 8/11/2008 11:15:52 AM , Rating: 2
> "This would make same day trip to the moon or would it be like using a hammer to kill a fly?"

In terms of fuel required, Mars is only 50% further away than the moon (or ~100% if one assumes constant thrust propulsion), so one certainly could use this for trips there.


ERROR
By Comdrpopnfresh on 8/11/2008 8:52:16 PM , Rating: 2
quote:
Plasma rockets are considered by many the best long-range propellant solution besides fusion rockets. As fusion power is still a fledgling research field , plasma may help to fill the gap for many years to come. Past fusion power, only exotic propulsion solutions could possibly yield greater speeds.


Are you talking about fusion electrical power, or thermonuclear rockets?
Fusion power perhaps is a up and coming field of research, but the truth is that rocket technology was developed in the 50's and 60's which already outstripped chemical rockets. If hadn't been canceled in 1972, all the kinks would likely have been worked out, and a successful platform would have likely been created, based off of the space shuttle assembly.

The program was called NERVA:
http://www.daviddarling.info/encyclopedia/N/NERVA....
http://www.astronautix.com/engines/nerva.htm

It succeeded in being built and providing a specific impulse of ~850 sec. That was nearly 50 years ago.




RE: ERROR
By masher2 (blog) on 8/11/2008 9:14:57 PM , Rating: 2
NERVA was a fission-based design, not fusion.


RE: ERROR
By Comdrpopnfresh on 8/11/2008 9:42:28 PM , Rating: 2
Admittedly, any replies or comments I have aren't limited to the constraints of correctness that an author of an article is typically held to. That's a basic principle of ethos.
That being said:
quote:
Are you talking about fusion electrical power, or thermonuclear rockets?
Fusion power perhaps is a up and coming field of research, but the truth is that rocket technology was developed in the 50's and 60's

In my first sentence, I was trying to find out what the author implied by "fusion power." I didn't intend to imply NERVA was fusion-based. Thermonuclear rocketry would likely fall under the Orion and/or Daedalus projects- but my aim was to point out a successful creation of a non-chemical propulsion (NERVA) which had competent ISPs, nearly 50 years ago.


RE: ERROR
By masher2 (blog) on 8/11/2008 10:29:12 PM , Rating: 2
My apologies then. I'm a big fan of nuclear thermal propulsion; there are few mistakes the US made larger than its decision to abandon such research.


RE: ERROR
By Comdrpopnfresh on 8/12/2008 3:52:51 AM , Rating: 2
Same here, and agreed. They definitely should have learned their lesson of the value of nuclear tech and space when, in all likelihood, the first man-made object to enter orbit was a manhole-like steel cover of an underground nuclear test! haha. That thing beat out sputnik by a good chunk of time. I'm studying to be a NucE, so stories like that are kind of our professional rumor mill bread and butter.


It couldn't hurt to do some reporting
By nofranchise on 8/11/2008 10:34:14 AM , Rating: 3
Although all articles about advances in space flight are welcome, this one is a bit botched.

Most of Jason's article is based on an incredibly old article from space.com - from june 16th, 2000, eight years ago.

Now I know this is an update, but it's embarrassing to use so many direct quotes from such an old article.

Come on DT - do some reporting instead of just being a xerox machine.

Wouldn't it be satisfying for you Jason if those quotes - or others - had actually been made to DT? How hard would it be to shoot an email at Dr. Chang-Diaz and his team? Even a phone call?

As a science reporter I find this excuse for "journalism" sad.




By Cheapshot on 8/11/2008 10:59:54 AM , Rating: 2
To be honest... the only thing that concerns me is that it's ready for testing. And I didn't read the original article.

So many theories and concepts pass thru DT that a simple "it works!" is news enough.


RE: It couldn't hurt to do some reporting
By DNAgent on 8/11/2008 1:23:34 PM , Rating: 2
Are the pictures from 2000 as well? Or have these guys been pinching pennies by using bargain bin CRT monitors? o_O


By nofranchise on 8/12/2008 4:56:35 AM , Rating: 2
All the pictures except the last one are from the original Space.com article/original pressmaterial from 2000...


Power source?
By HammerFan on 8/11/2008 11:57:40 AM , Rating: 2
What's the onboard power source for this thing? Also, 450s Specific Impulse was nearly achieved in the 70's with NERVA, and undoubtedly, with a little more work and modern materials, we could far surpass that level, and use it to lift off the ground (even though the greenies really would have a fit). With a viable power source, this technology could definitely shorten travel time outside of a gravitational field, but that doesn't help if you can't get off the ground.

my $.05




RE: Power source?
By Shadowself on 8/11/2008 12:27:35 PM , Rating: 2
The 450 seconds Isp is for the shuttle main engines. They are rated at 451 seconds IIRC. The shuttle main engines are some of the highest Isp chemical engines used to date.

NERVA and others were very different engines... effectively "nuclear torches" as the propellant flowed through heart of (or in some designs, around the immediate periphery of) a nuclear reactor.

But to your initial question, this does take massive amounts of electricity. Thus it will need very large solar arrays or it will need a nuclear source (probably a reactor) to power it.


RE: Power source?
By chromal on 8/11/2008 1:12:51 PM , Rating: 2
Thanks for pointing out the power requirement. I was going to say, there must be a hefty electrical source. I wonder if they could really do the "2-3 months to mars" burn with solar... If they need a reactor, I say go for it. Nukes make perfect sense to me for powering interplanetary missions.


RE: Power source?
By FITCamaro on 8/11/2008 1:20:31 PM , Rating: 3
Tell that to environmentalists who oppose anything nuclear. On this planet or off it. Hell if god had environmental activists monitoring him when he created the universe, they'd have tried to get the sun outlawed.


Speaking of plasma (and microwave ovens)...
By fibreoptik on 8/11/2008 11:02:43 AM , Rating: 2
... did that remind anyone else of the awesome split-grape-in-the-microwave experiment?

In case you haven't seen it (or don't remember), check it out on YouTube --> http://www.youtube.com/watch?v=_ux8nSWmAz0




By JustKidding on 8/11/2008 11:53:39 AM , Rating: 1
I wish Jason would show the entire engine diagram, he left out the part showing where the astronauts put the grapes in...


By fibreoptik on 8/11/2008 12:43:37 PM , Rating: 2
I figured they were going to catch the omission of the grapes and upload a new, corrected diagram but I am still waiting...


Losing Containment? All hand abandon ship!
By wingless on 8/11/2008 1:26:10 PM , Rating: 2
I hope these rockets will have the option to jettison the Warp Reactor when the magnetic fields start to collapse and you lose plasma containment. I think we've all seen enough Star Trek to realize what happens if you can't jettison the reactor! KABOOM!




By bobsmith1492 on 8/11/2008 5:42:29 PM , Rating: 2
Something about non-volatile fuel comes to mind...


This article is really, really terrible
By Laereom on 8/11/2008 1:30:02 PM , Rating: 2
I remember reading about VASIMR in 2004-5ish, when Ad Astra was new news. It was originally a NASA project run by our friend Chang-Diaz, but the project was receiving insufficient funding, and was to be cut entirely due to the new back to the moon thing that was just coming off the ground. Chang-Diaz convinced 'em to give him the IP and either founded (or joined...I can't quite remember) Ad Astra to continue its development.

Here's an article from back when VASIMR was a NASA thing:

http://www.space.com/businesstechnology/technology...

Since the ISP was lower than traditional ion drives, it wasn't really being looked at as a near-term propulsion solution. The energy efficiency was nominally lower, to be sure, but the real advantage was in capacity -- while ionizing grids could only create so much plasma, RF contained in a magnetic bottle would scale up virtually limitlessly to the capacity of your energy supply.

The problem then, as well as now is the power source. Where do you get enough energy to constantly produce several the dozen megawatts of electricity necessary for truly impressive thrust? The only real option is nuclear power. With a nuclear fission reactor, VASIMR becomes a real option. Furthermore, should it be scaled hugely, VASIMR could be used as a fusion rocket (using aneutronic fusion reactions, of course) -- that way, once you get it going, it produces massive amounts of thrust as well as functioning as a power plant for the rest of your ship.

Some day. Maybe. Until then, though, saying VASIMR could bring us to mars in 2-3 months is like saying you have a power train and tires that can travel at 500mph -- yeah, sure, but with what engine?

And for those of you worrying about safety, VASIMR was tested on earth a few times in NASA's labs, producing measurable quantities of thrust -- on the order of two or three nickels on your palm worth. :P




By Dan T on 8/14/2008 11:05:58 AM , Rating: 2
To expand on more speculative space propulsion, see:

http://nextbigfuture.com/2007/11/fusion-propulsion...

Bussard developed the Bussard Ram Scoop interstellar drive concept, and was involved in the developement of fission rockets in the 1960's. In 2005 his group developed a Fusion reacter design that he claimed was workable as a net power generation system. Currently the 'Polywell' system is being retested and is currently undergoing peer review. We should know within the next few months if it works as advertized (if it isn't classified by the Navy). It would provide all the power needed for his ideas, or to power a VASMIR design.

Dan


Awesome
By FITCamaro on 8/11/2008 11:03:36 AM , Rating: 1
One step closer to the day space travel in our own solar system is not a years long ordeal. We need to get the time required to get to Mars down to a week at most. Not months.

Need those impulse engines boys. Then get to work on warp drive. :)

And actually if I recall, the principles behind warp drive aren't impossible as there was a lot of scientific collaboration on the show. The problem is a power source. If we could ever produce a stable matter/anti-matter reaction, it could be possible.




RE: Awesome
By Cheapshot on 8/11/2008 12:13:39 PM , Rating: 2
...and figure out the whole spacetime/ time dilation thing.


"exit" is not a transitive verb
By androticus on 8/11/2008 2:31:07 PM , Rating: 2
dude, c'mon...




By phxfreddy on 8/16/2008 8:22:29 PM , Rating: 2
........ a nuclear reactor to be lifted into orbit! This will be required to power this thing. I do not solar will cut it.....

Whilst I like this idea the environMENTAL cases will have hissy fits saying

"There is too much danger putting a reactor in orbit!"

Again they will stand in the way of progress. Just like all their other luddite causes they will slow the progress to Mars.




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