NASA Plans Test of New Plasma Drive

Sallust writes "Flightglobal has an interesting article about the testing of a new electrically powered plasma engine called the Vasimir. It's being developed by former astronaut Franklin Chang-Diaz and promises to greatly reduce the time and fuel required for interplanetary journeys. According to the article: 'The Vasimir involves the injection of a gas such as hydrogen into an engine that turns it into a plasma. That plasma is then energised further using radio signals as it flows through the engine, a process controlled by electromagnetic waves from superconducting magnets. Accelerated and heated through this process the plasma is focused and directed as exhaust by a magnetic nozzle. Vasimir is many times more efficient than conventional chemical rockets and far less fuel is needed.' The developers are finalising an agreement with NASA to fit a scaled-down version of the engine to the ISS to conduct operational tests. There is also a concept video on YouTube suggesting a journey time for a manned craft to Mars on the order of 60-70 days."

Comments

plasma exit velocity?

[oldspewey]

Neither summary nor TFA give any indication of the velocity of plasma exiting the engine. How does it compare with chemical rocket? Ion drive?

Re:plasma exit velocity?

[wurp]

This sounds a lot to me like it *is* an ion drive. I didn't RTFA, but a plasma is characterized by a separation of the electrons from the nuclei. The only difference between that and an ion drive is that not necessarily all electrons are stripped from the atom in an ion drive.

I don't know how (or if) you would distinguish between ionic hydrogen and a hydrogen plasma (hydrogen atoms have only one electron...)

In both cases you give the propellant momentum with either electric or electromagnetic force, and both are much more efficient than chemical rockets. I would also expect both to have miniscule thrust compared to chemical rockets, and hence only be appropriate for navigation when you already have orbital or superorbital velocities.

Re:plasma exit velocity?

[AKAImBatman]

Good catch. So 8.5 months for a one-way trip vs. 3 months. I'll take the VASIMR any day of the week. :-)

Re:plasma exit velocity?

[mi]

However, the VASIMR rockets have a range of specific impulses from 3,000 to 30,000 seconds.

This is the part I don't get, but you probably do. Why would I lower the exhaust speed, instead of lowering the mass?

The distances a spacecraft can travel in a given time are limited by the mass of "stuff" it can throw back multiplied by the speed, with which it is thrown. So, one would think, the most efficient engine would be throw "stuff" out as fast as it can, and if lower thrust is desired at times, it would throw less of it instead of throwing the same amounts at lower speed...

Or is varying the amount at will simply too difficult today and requires another 10 years of research?

Re:plasma exit velocity?

[marco.antonio.costa]

In most ion drives there is interactions between the electrodes and the propellant, reducing reliability and maximum input too, I believe.

In the VASIMR the electrodes and propellant are completely separate by the containing magnetic field, which also means that the temperature of the plasma, thus propellant speed, is only limited by the power used to heat it, up to fusion temperatures, which is hellishly cool.

This gets my geek insticts completely haywire, sorry for the fanboyish post. :P

Nice to see fact moving faster than fiction

[CRCulver]

Who knows if this thing will work out, but it would be amusing if it did. In histrilogy beginning with Red Mars , Kim Stanley Robinson had interplanetary journeys being trimmed down to such short lengths only a couple of hundred years from now, and KSR's work tried hard to be scientifically plausible.

Re:Nice to see fact moving faster than fiction

[spun]

Fact is often capable of moving faster than fiction, it just takes a collective decision to make it so. We could have been to Mars already, just like we could be feeding everyone in the world. We just don't care enough.

Re:Nice to see fact moving faster than fiction

[rubenerd]

You're absolutely right. Collective will of corporations, governments and people (land, labour, capital and enterprise for those economically inclined) towards a single goal in the past has resulted in amazing things being achieved. Alas it's just too uncommon for all three groups to be interested in the same things at the same time, because they have different priorities and perceived needs.

What I'm hoping for now is that with the shrinking of the world there is a huge opportunity for corporations, governments and people to work together regardless of their geographic location quite unlike any other period in our collective history.

Optimistically, together we can achieve so much. Realistically, I think we're still more interested in spending our land, labour, capital and enterprise resources on killing each other over differences such as religion, resource allocation and political ideology.

As a terribly politically incorrect end note though, the jet turbine engine was created as a direct result of war. Who knows, a new cold war may have people racing to other planets, comets or solar systems instead of our moon. It's interesting to think about: how much of our progress is just making sure someone else doesn't do it first?

Engine?

[jdb2]

Engine? The scaled down test version might use something "conventional" as its power source, such as an RTG. But, in order for the VASIMIR to work at full-scale, say in a human Mars mission, the power source is going need a VERY large energy density -- something not achievable with any known and tested chemical reaction. I have no idea why they call the power source the "engine" but perhaps it's to placate the environmentalist wackos who will go nuts after hearing the obvious : the "engine" or power source is a nuclear reactor. It will be interesting ( and probably funny ) to see how this plays out in the long run if NASA sticks with this technology.

jdb2

Re:Engine?

[jdb2]

Good luck with that. Not only a nuclear reactor, but a heat exchanger, a turbine, and a generator.

Uhhhhh? Have you ever heard of nuclear thermal rockets? NASA's NERVA program? You know a nuclear reactor can heat substances other than just water. I don't know if you were trying to be funny because "a turbine, and a generator" is just stupid.

That's a lot of complexity for a space mission.

And what space mission is not complicated? There's this thing called "technology" that improves exponentially with time and better technology allows greater complexity.

There are more direct ways to generate electricity with nuclear reactions, but none are really practical for this sort of power output, that I'm aware of. I'm thinking a more straightforward application of nuclear power would work better. Something like this.

I had thought of Antimatter, but we're talking about a near term mission that uses proven and tested technology. ( for its energy source ) Maybe in 50 years we'll be using antimatter for all our energy storage needs, but that implies we'll have large supplies of Anti-Hydrogen ice. Can you tell me where I can buy some today? ( By the way, I'm not a skeptic when it comes to Antimatter based energy storage and propulsion. The problem now is that current particle accelerators are designed to study particle physics, not to produce antimatter. In fact, Robert Forward showed that if we were to build accelerators specifically designed to produce antimatter,( perhaps a special linear wake-field accelerator ) we could potentially produce at least 1 milligram per year at a cost of only around a 10 million dollars. If one where to use many accelerators in parallel that where able to produce higher energies, that amount might be up in the gram-kilogram range.)

jdb2

Re:Engine?

[avandesande]

I know this technology is in its infancy but beaming microwave energy to an antenna might work.

Re:Engine?

[CrimsonAvenger]

It will be interesting. However, we've known for a long time that a nuclear reactor would be the best fuel source for a space vessel. Truth be told, it's probably safer to put a nuclear reactor in a spacecraft then in a submarine or aircraft carrier, and the Navy does that all of the time (and it would be more environmental... out in space, you wouldn't have the radioactivity in the oceans). Considering most sub reactors get >100 MW, 200 kW isn't a big deal, and you can power the ship off of it too.

Submarine reactors don't dump radioactivity into the oceans, either. The primary loop (the water moving from the reactor to the steam generators) is a closed loop. The secondary loop (the steam from the steam generators to the turbines to the condensers) is also a closed loop. The only seawater is the coolant for the condensers, which never comes in contact with the (non-radioactive) water of the secondary loop, which (non-radioactive) water never comes into contact with the (not terribly radioactive) water of the primary loop.

I agree that 200KW isn't that big a deal. What you're looking for is the highest power to mass ratio reactor you can manage. Which isn't necessarily the same as the size range for a submarine reactor, since there isn't an ocean out in space to dispose of the waste heat from the secondary loop. Getting rid of that waste heat would likely be the largest part of the mass of the reactor used to power a VASIMR.

FYI

[Anonymous Coward]

Just to make sure people know, VASMIR is basically an Ion engine that you can throttle the Specific Impulse. Hence if you need a sudden acceleration you can make that happen, but at the cost of fuel efficiency, or on the flip side if you need something efficient and don't care how long it takes either way VASMIR is the engine for it...I really look forward to when they start using it regularly

Ad Astra

[Anonymous Coward]

I was surprised to see that NASA allowed this development to go on in Costa Rica. Chang-Díaz may have the company in Texas, but the bulk of the operation is out of Costa Rica. Little Security on this project. In fact, if you hire on in America, you need a security clearence, but in Costa Rica, none. More importantly, the bulk of the design work is being done in Costa rica.

Re:Yes, attach it to the ISS

[Amouth]

actualy because this design heats the gas to a plasma state then uses EM waves to move it to create thrust - the idea could be used on just about any gas - your effeciency would be how much energy goes into heating it to a plasma state and keeping it there.

this is a great idea because they could design one engine and while the gas is consumed it could be replaced by any gas - and electricity is the true source of the power to run the engine..

we already know what gasses are readly avaliable on mars - design one to run on say H to get there (assume Hyrdogen is the easiset to heat to plasma sate) but have the engine also able to run on the gasses from Mars.. then when it gets there refill the tanks.. carge up the batteries (or use a nuke power source on the thing) and come on back - or keep going.

think of a ship with this type of drive.. then think about adding say a Bussard collector http://memory-alpha.org/en/wiki/Bussard_collector (i know we would have to invent a bussard collector but the idea is not that hard)

if this works they way the say it does - it is going to be one of the best propultion advances for traversing our solar system.

and with us having probes leaving our system - the data from there might show that there is a good ammount of particals in the space between systems.. if that is true then you could use this to send probes to other systems. sure it would take awhile but i bet they can alwasy make improvements.

VASIMR Info available on Atomic Rocket Page

[dlapine]

Try this Atomic Rocket website for some more information on this type of engine outside of Wikipedia. What's interesting about this type of engine is that it's capable of trading thrust (what you want to liftoff) for Specific Impulse (what you want in orbit to get best reaction mass efficiency).

This is a pretty good site for information on all types of potential/possible/theoretical propulsion systems, and what it would take to do "real" solar system space travel. That being said, space travel (even within the bounds of just our solar system) via our current level of technology bites.

As someone else noted, this type of propulsion requires about 10MW of electrical energy to function. That energy is not provided by the propulsion system. Something else has to provide it in a compact, dense and energetic form- namely a nuclear reactor onboard the craft. That's why this type of engine shows up at the "Atomic Rocket" website, even though the engine itself doesn't use any nuclear reactions. Some people might not appreciate that the exhaust is not radioactive, as the power plant is just used for electricity.

Unlike a chemical rocket, a spacecraft using this engine would be able to get to orbit with some payload, and would not resemble "a disintegrating totem pole" getting there. Unfortunately, it also requires a nuclear reactor, a VASMIR engine, a large amount (50-75% of the whole thing) of reaction mass, and probably, wings.

Re:New, it is not

[Nef]

Seriously, it's only 200 kW? That being the case, a few square meters of solar panel should do just fine, even at Mars like distances, you'd still be getting enough energy that it would be trivial ( something like 5 square meters would be sufficient at even Mars furthest distance of 2.5EE6 KM from the sun)

Yes, I know my figures aren't exact, but this is /., so I'm sure someone will come along and actually do the calculations.

Re:Yes, attach it to the ISS

[Omega996]

yeah, designing and building a bussard collector isn't that hard, it just needs something that can generate a magnetic field that doesn't diminish as the inverse square of the distance, since your magnetic or electrostatic funnel would have to be huge to pull in enough material to be worthwhile (even inside the heliopause). unless you're planning on not using a vehicle with any live crew or any sort of electronic equipment. I'm sure the difficulty of initiating and sustaining a proton-proton fusion to generate plasma is just a quick fix (no doubt you've already figured out the materials and fuel source for your carbon-nitrogen-oxygen fusion catalyser), as are the problems associated with getting the ramjet to speeds above the solar wind (unless the vehicle is making a quick one-way trip into the sun).

not much to do there, at all. You should get right on it, and we'll be heading toward Mt. Lookitthat within a few months. *rolleyes*

Re:All they have to do now...

[fm6]

And this is superior to simple (relatively non-lethal) copper wires because...?

Re:Yes, attach it to the ISS

[nacnud75]

The Environmental Control and Life Support System (ECLSS) planned for the ISS will use recycled water and split it into Oxygen and Hydrogen. The Oxygen is used to support the crew while the hydrogen is dumped. A VASIMR might be able to use this hydrogen to reboost the station, reducing the need for ISS resupply with toxic propellants.

BCReason

[bcreason]

I'm waiting for the Dirt Drive . Same concept as the Vasimir but instead of throwing Hydrogen away as propellant you use Silicon, the main component of dirt.

Why use precious hydrogen that can be used to make water when you could use dirt. The Moon has dirt, Mars has dirt, most asteroids have dirt.
(Technically it's regolith, but regolith doesn't sound as cool)

I know it will take some serious engineering to make a drive that uses a solid fuel. I'm thinking vaporize it with lasers, then everything else is pretty much the same as with the Vasimir.

Advantages over Hydrogen:

• Easier to obtain
• Easier to store, no pressure vessels required.
• More compact to carry.
• Has more mass, therefore more thrust.
• Safer, non flammable and not stored under pressure. No chance for an explosion.
• Safer, wont leak away if a storage container is holed.

Gaseous Core Nuclear Reactor

[serutan]

A gaseous core reactor would radiate ultraviolet energy directly to the hydrogen, eliminating the need to generate electricity. Take a look at this article about a hypothetical design for a non-polluting, 100% reusable nuclear rocket using the Saturn V form factor that could lift 1000 tons of payload into Earth orbit and return an equal payload to a powered landing.