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Concept art, shows the VASIMR engine powering a moon mission.  (Source: Ad Astra)

The VASIMR engine is of an electric rocket design. This type of rocket is trickier to perfect, but performs better than a chemical rocket, with increased speed, lower costs, and better safety.  (Source: Ad Astra)

A VASIMR engine is shown here in action, generating plasma thrust.  (Source: Ad Astra)

Ad Astra envisions a rich market of spaceflight applications.  (Source: Ad Astra)
Former NASA astronaut turns heads with his innovative engine

Commercial space flight is very expensive.  As a result of its reliance on chemical boosters, the cost of flying a single pound into space aboard the space Shuttle to approximately $5,000 to $6,000.  The cost of launching space missions to far-away bodies such as the Moon or Mars grows exponentially higher -- it is estimated that the cost of sending one pound sent to the Moon is around $200,000.  These extreme costs have put longer manned commercials spaceflight out of reach, with the commercial space industry instead turning to a few luxury tourism startups.

While much of this fuel is expended on launch, some is also expended in the vacuum.  And as longer missions are attempted, the need for more efficient rockets operating in the vacuum increases.

A new engine, named VASIMR, could provide exactly the solution needed.  Developed by former astronaut Franklin Chang Diaz, the engine could change a lot about how we interact with space.  The new rocket, driven by plasma, is able to use cheaper fuels like neon, argon, or hydrogen, while providing finer control over thrust and specific impulse -- two key parameters that determine a rocket's movement and speed.  The new rocket is also much safer and more reliable than traditional chemical rockets, reducing the risks associated with space flight.

The engine exhausts plasma, a fourth state of matter along with solids, liquids, and gases.  Plasma is essentially ionized gas.  It is typically created via either low pressure or extremely high heat (10,000° C or more).  Plasma consists of a mix of electrons and positively charged gas ions.

No known material can contain plasma, so VASIMR instead uses magnetic fields for containment.  It uses radio frequency waves to ignite and throttle the rocket precisely.  The rocket is capable of long burns, with its long term goal being to produce enough sustained thrust and impulse to reach Mars in under three months.

The new engine is the flagship technology of Mr. Diaz's startup, Ad Astra Rocket Company.  After three decades of development at NASA, MIT, and elsewhere, the rocket engine is finally approaching commercial readiness.  The rocket recently passed a momentous milestone -- 200 kilowatts of power, the amount necessary for the company to start developing its flight version.

According to Mr. Diaz, "[Ad Astra is] getting ready to fly the VASIMR engine on the International Space Station (ISS). It is a 200-kilowatt plasma rocket, the most powerful rocket ever built to fly in space, and the prototype is being tested on the ground in our facilities in Houston. We have been gradually ramping up the power over many months, and our goal is to reach 200 kilowatts, which is the power level the rocket will run at on the ISS, and we achieved that today. We actually reached 201 kilowatts. It was a very exciting moment because it happened right when we were in the meeting, and I kept getting text messages."

The rocket will be first tested in space in October 2013, aboard the International Space Station.  Describes Mr. Diaz, "We will install it on the ISS and test it there. After the test is finished, we will use it commercially to reboost the space station [to a higher altitude] to provide the drag compensation. [Currently the ISS requires periodic boosts to get it to the right orbit for space shuttle or Progress dockings.]"

Ad Astra is trying to convince NASA to enter a greater contractual relationship with it to lower costs manned and unmanned space missions, via use of the VASIMR engine.  Given the shaky state of NASA's Shuttle-successor, Orion, that certainly seems possible.  Founder Diaz believes that using commercial bidding and innovation are key to NASA and other international space organizations lowering their costs, as well as the key to getting other commercial entities involved in the space industry.

Mr. Diaz explains, "The agency really transformed the world in space with the achievements of the moon landings, but the whole world changed, and NASA didn't change. NASA remained in the glory days of the past, and 40 years have gone by, and NASA is still the same NASA as the 1960s. And I don't mean it in a bad way. It was so wonderful what was done, and people were completely fascinated by it. But a new opportunity has been created because NASA's fascination with its own past in the present has created a gap, a hole, which is perfect for the private sector to move into.

"The private sector is going to fill the void in rapid access to low earth orbit, allowing NASA to be NASA, to do what NASA was really meant to do, which is look forward to the frontier. Let the private enterprise build the base camp now that we know how to do it, and NASA can go conquer the summit."

The startup is in talks with two space tourism companies -- SpaceX and Orbital Sciences -- to create the body to house the VASIMR engine and finish a contract-ready rocket, which would incorporate efficient chemical boosters to reach orbit and then fire the VASIMR to continue its spaceflight.  Both of these organizations have the advantage of access contracts to the ISS -- Ad Astra is currently trying to figure out which best meets its needs.



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Power =/= Thrust
By Amiga500 on 10/7/2009 9:29:19 AM , Rating: 2
What is the thrust rating?!?! How efficiently is the input power converted to useable thrust?




RE: Power =/= Thrust
By Amiga500 on 10/7/2009 9:30:55 AM , Rating: 1
Ach... after a moments digging...

... 5 Newtons.

Not a real landmark day for space exploration just yet!


RE: Power =/= Thrust
By MozeeToby on 10/7/2009 11:12:48 AM , Rating: 5
5 Newtons that can be run continiously for weeks, months, or years is absolutely news. Look at it this way, if you have a 500 kg probe and a motor that can produce 5 N for 6 months, the final velocity of that probe is 150000 m/s.

That's quick enough to get a probe past Pluto in less than a year, without gravity assists (presumably it would be much faster with them). It's more than enough to revolutionize our unmanned missions.


RE: Power =/= Thrust
By Chernobyl68 on 10/7/2009 12:33:00 PM , Rating: 2
I don't know what its fuel consumption is, but since it uses much simpler gases as fuel (as opposed to more dangerous chemicals in chemical rockets) means it could be easily refueled on the space station if the need arose.


RE: Power =/= Thrust
By stromgald30 on 10/7/2009 1:26:26 PM , Rating: 2
While what you're saying is true, VASMR engines do bring about many of the other issues that already exists with current ion thrusters, specifically the warm-up time (no last minute escapes with this engine), the high EM field (can't put this thing anywhere near computer boxes), and the high likelihood of building up a significant electrical charge on the vehicle (which can also disturb on-board electronics).

So, yes it's safer from a toxicity or blow you out of the sky standpoint, but it's not necessarily safer from an overall mission standpoint.


RE: Power =/= Thrust
By jimwhd on 10/7/2009 2:42:34 PM , Rating: 2
quote:
While what you're saying is true, VASMR engines do bring about many of the other issues that already exists with current ion thrusters, specifically the warm-up time (no last minute escapes with this engine), the high EM field (can't put this thing anywhere near computer boxes), and the high likelihood of building up a significant electrical charge on the vehicle (which can also disturb on-board electronics). So, yes it's safer from a toxicity or blow you out of the sky standpoint, but it's not necessarily safer from an overall mission standpoint.


Couldn't the electrical charge on the vehicle be discharged in the same manner that is used in commercial aircraft via a "static wick"?


RE: Power =/= Thrust
By Ringold on 10/7/2009 3:16:42 PM , Rating: 2
My understanding, at least as told to me by a flight instructor back in the day, is that those "static wicks" disperse the charge in to the air behind the aircraft. No air in space?


RE: Power =/= Thrust
By Hogger1 on 10/8/2009 8:18:02 AM , Rating: 5
"But there is an Air n Space Museum." Homer S.


RE: Power =/= Thrust
By bug77 on 10/7/2009 5:17:57 PM , Rating: 2
Not to mention that "no known material can contain plasma". Still, a whole new way to look at space flight cannot be a bad thing.


RE: Power =/= Thrust
By stromgald30 on 10/8/2009 5:25:22 PM , Rating: 2
You don't have to contain plasma and deliver it on-board. Plasma is created from electricity and inert gas (Argon, Xenon, etc). The inert gas can be delivered on-board much more easily than chemical propellants.


RE: Power =/= Thrust
By MrPoletski on 10/12/2009 6:29:18 AM , Rating: 2
How will you end up with a significant electrical charge building up?

what is doing the charging, bearing in mind that this fuel plasma will not come in contact with any part of the ship because it is electromagnetically contained - and hence no charge from it will conduct to the ship either.

Ion drives will charge your ship because you are deliberately ionising matter that you make no real effort to prevent from contacting the ship.

Also, when you are not thrusting, what is to stop you holding some superhot plasma ready to go? It will cost energy, sure, but it'd certainly be worth doing in the case of anticipating possibly needing an emergency burn.


RE: Power =/= Thrust
By stromgald30 on 10/12/2009 1:15:08 PM , Rating: 2
Plasma contains a mix of ions. When you heat almost any gas to the temperatures of plasma, it ionizes. However, unlike ion drives, both positive and negative ions are exhausted together, so there's no need for neutralizing the charge at the exhaust with a cathode.

One of the biggest issues with the VASIMR is the fact that there is a tendency for the plasma ions to follow the magnetic field lines around to the front of the engine (you can't have a magnetic monopole). This would charge up the ship if the ions are cool enough or damage it, if they're still in plasma form. It never comes up in laboratory tests because the way the test cells are set up prevents this problem. It's not an insurmountable engineering problem, just one that requires space trials and careful usage of the engine.

Holding plasma in the chamber is possible, but I'd be more concerned with damage to the engine rather than power (since this thing is supposed to used 24/7). Think of shooting water through a pipe. If the water's fast enough, it won't go into any 90 degree branches off the straight pipe. However, if you try to just hold the water in the pipe or slow the flow, it will expand/fill areas you don't want it to get to. The magnetic field to contain and accelerate the plasma isn't perfect. There will be weak spots. Holding plasma for long periods would be asking for trouble in stray plasma molecules contacting the inside of the chamber.

I don't mean to come off as bashing the new technology, I just know of some limitations and think that it will not completely replace the current chemical engines.


RE: Power =/= Thrust
By MrPoletski on 10/13/2009 5:26:34 AM , Rating: 2
Would be nice if it could use helium, the by product of nuclear fusion.

Then this engine could be combined with a fusion reactor (when we get them working proper) for super space age fun!


RE: Power =/= Thrust
By Amiga500 on 10/7/2009 12:41:49 PM , Rating: 2
(In my opinion) the real problem is not travel in space - simple inertia takes care of that. You get there eventually.

The real problem is getting out of the earth's gravity well.

An ion engine that can feasibly replace the chemical rocket on a 3rd stage of a launch vehicle would be groundbreaking. Unfortunately, this isn't there yet.


RE: Power =/= Thrust
By JasonMick (blog) on 10/7/2009 1:15:59 PM , Rating: 2
Combine this thing with a space elevator and you're good to go.

...of course a space elevator is going to take a bit longer, but there has been a lot of good progress in that front as of late, too.


RE: Power =/= Thrust
By kattanna on 10/7/2009 1:24:06 PM , Rating: 5
quote:
...of course a space elevator is going to take a bit longer, but there has been a lot of good progress in that front as of late, too.


since im still laughing, we have at least another 50 years

;>)


RE: Power =/= Thrust
By EricR on 10/7/2009 3:33:09 PM , Rating: 2
quote:
5 Newtons that can be run continiously for weeks, months, or years is absolutely news. Look at it this way, if you have a 500 kg probe and a motor that can produce 5 N for 6 months, the final velocity of that probe is 150000 m/s. That's quick enough to get a probe past Pluto in less than a year, without gravity assists


Hmm,

150000 m/s (or 335540 mph) = Don't blink or you'll miss it!


RE: Power =/= Thrust
By Etsp on 10/7/2009 4:40:51 PM , Rating: 5
That's 93 miles per second. It's likely you'll miss it even if you don't blink!


RE: Power =/= Thrust
By MrPoletski on 10/12/2009 6:08:19 AM , Rating: 2
93 miles per second...

Well, only 186,123 miles/s to go then...;)


RE: Power =/= Thrust
By Morro on 10/7/2009 8:55:37 PM , Rating: 2
Ok, for 500kg probe traveling at 150000 m/s and having thrust of about 5N and acceleration of 0.01 m/s^2 (F/m) will result in kinetic energy increase of about 750kW per second. Not bad for 200kW engine ;)


RE: Power =/= Thrust
By Morro on 10/7/2009 8:57:13 PM , Rating: 2
I meant KJ per second, as you can guess..


RE: Power =/= Thrust
By Hyperion1400 on 10/8/2009 10:19:51 AM , Rating: 2
Deep space kinetic energy weapons anyone? >:)

"Opps, sorry China, we were trying to puss that 2 kilometer wide asteroid into to orbit to try and harvest it. It slipped, honest!"


RE: Power =/= Thrust
By 91TTZ on 10/7/2009 4:05:28 PM , Rating: 2
quote:
5 Newtons that can be run continiously for weeks, months, or years is absolutely news. Look at it this way, if you have a 500 kg probe and a motor that can produce 5 N for 6 months, the final velocity of that probe is 150000 m/s.


But how would you power it? This engine made 5 newtons at 200KW. RTG's are usually the powerplant of choice, but their power output is low, usually only a few hundred watts for a device weighing a hundred pounds or so. This engine would require almost a thousand times more power.


RE: Power =/= Thrust
By manofhorn on 10/7/2009 10:41:10 AM , Rating: 2
and am i really missing something here, or is 200kw just over 250 horsepower? THAT'S the most powerful rocket ever built to fly in space?


RE: Power =/= Thrust
By Amiga500 on 10/7/2009 10:47:04 AM , Rating: 2
No, well.

Thats kinda what I was asking.

200kW/250hp is the power rating at the engine crankshaft so to speak.

I was wondering what the 'power rating' at the wheel hubs were.


RE: Power =/= Thrust
By MozeeToby on 10/7/2009 11:20:52 AM , Rating: 3
It has the highest Delta V of any rocket in space, not highest power. A chemical rocket will produce much, much more thrust but can only run for a very short time and requires a lot of fuel to power it. This thing produces very little thrust (5 N) but can run for months and uses very little fuel. Having to take less fuel further increases the efficiency since you don't need to haul as much fuel with you.

The practical upshot of all that is very slow accelleration but a very high top speed, much higher than is possible with chemical rockets. Or, alternatively, the ability to stabalize a satellite/space station orbit without having to constantly send up more rocket fuel to do so.


Use...
By bradmshannon on 10/7/2009 9:32:24 AM , Rating: 2
I haven't seen this clarified anywhere, but I'm assuming that this engine is only useful in space, right?




RE: Use...
By webstorm1 on 10/7/2009 9:40:38 AM , Rating: 5
as stated below, it only works in a vaccuum.


RE: Use...
By Entropy42 on 10/7/2009 10:35:46 AM , Rating: 6
It only works in a vacuum.


RE: Use...
By Yawgm0th on 10/7/2009 10:49:03 AM , Rating: 2
I lolled at this. +1


RE: Use...
By rlandess on 10/7/2009 11:00:44 AM , Rating: 2
I don't think a vacuum has anything to do with it. I was under the impression it was useful only once it has been placed in orbit. Chemical rockets can achieve a greater amount of thrust to reach orbit, but the ion rocket is more efficient for propulsion once in orbit.


RE: Use...
By stromgald30 on 10/7/2009 1:18:44 PM , Rating: 2
Actually, it does have to do with whether it is in a vacuum. The magnets that are used to accelerate the heated plasma aren't strong enough to move against atmospheric pressures.

Basically, it's a function of thrust vs. area. 5N of thrust over the size of the relatively large thruster exit means very low exhaust pressure (not enough to overcome the 14.7 psia of atmospheric pressure).


RE: Use...
By Shadowself on 10/8/2009 7:55:40 PM , Rating: 2
Go back and study high school physics. It has nothing to do with exhaust pressure versus air pressure. All rockets are action-reaction machines. With the velocity the individual ions are being moved out of the thruster there is no issue with vacuum or not.


RE: Use...
By stromgald30 on 10/9/2009 1:12:04 PM , Rating: 2
Lol, don't try to argue with me. I'm an engineer that works on rockets for a living.

Exhaust pressure is what counts for thrust. It is directly correlated with the chamber pressure and the nozzle geometry. For VASMR and other electric propulsion, the nozzle and pressure are EM field generated.

Exhaust velocity is used to calculate Isp or efficiency. The fact is that between the strength (or lack thereof) of the EM field and the mass of the particles, you can't apply enough force (Pressure = Force/Area) to push the particles out at a decent speed against atmospheric pressure.

So in short, why it doesn't work in atmosphere has everything to do with pressure. Why VASMR is better than chemical rockets (which I'm not denying) has to do with the higher exhaust velocity.


RE: Use...
By Omega215D on 10/7/2009 1:13:39 PM , Rating: 5
someone named Entropy has created a temporal paradox!


RE: Use...
By Spookster on 10/7/2009 4:50:01 PM , Rating: 2
quote:
By Entropy42 on 10/7/2009 10:35:46 AM , Rating: 6

It only works in a vacuum.


A Dyson I bet. It never loses suction...ever. It always sucks.


RE: Use...
By Shadowself on 10/8/2009 8:12:32 PM , Rating: 2
WRONG! WRONG! WRONG!

It does not require a vacuum to "work". The current designs work, by far, best in a vacuum. However, a VASIMR engine design does not REQUIRE a vacuum to work. One can be designed to work in atmosphere too.


RE: Use...
By stromgald30 on 10/9/2009 7:39:52 PM , Rating: 3
So bold letters and repeating it three times makes what you say true?

Here's evidence from the website of the company itself:
http://www.adastrarocket.com/missions.html

Yes, theoretically it could "work" (i.e. produce measurable thrust) in atmosphere with enough power, but like every other form of electric propulsion developed so far, it's essentially useless without a vacuum or insane power levels.


RE: Use...
By Gideonic on 10/8/2009 8:40:22 AM , Rating: 2
Yes, 5 Newtons is by far too little energy to lift anything useful. It's to accelerate a 5kg object at speed 1 m/s^2. As gravity on the ground is about 9,8 m*s^2, the engine could barely lift objects with the weight of about 500g, which is about 1.1 lbs. The engine itself weights considerably more.

In space though, where distances are enormous, small continuous thrust is much better than brief powerful acceleration, that chemical rockets provide.


come on 1MW
By kattanna on 10/7/2009 11:31:19 AM , Rating: 2
i'd like to see this engine stepped up to 1MW via nuclear and see just how well it performs in space.

build a craft using a cluster and send it out to tour the solar system and then move on out. shouldnt take long to pass up the voyagers.




RE: come on 1MW
By FITCamaro on 10/7/2009 12:26:03 PM , Rating: 2
Yeah it'd be nice if we'd finally get over our fear of anything nuclear in space.


RE: come on 1MW
By kattanna on 10/7/2009 1:23:16 PM , Rating: 2
too true.

its amusing that we really do have a LOT of nuclear stuff in space, most from military satellites that dont have to disclose what it is.

yet.. the world still turns.


RE: come on 1MW
By Scabies on 10/7/2009 1:47:28 PM , Rating: 2
http://en.wikipedia.org/wiki/Project_Orion_%28nucl...

That would have been fun... I dont think as many people would show up for the launch of one of these

more on topic, thanks to three mile island and Jane Fonda, combined with the loss of two space shuttles thus far (Challenger, Columbia), preeeettty sure that all kinds of people would flip to hear a nuclear power source was placed on any extra-terrestrial vehicle. if they even got as far as building one.


RE: come on 1MW
By kattanna on 10/7/2009 3:30:55 PM , Rating: 3
it REALLY didnt help that 13 days before 3 mile island the movie, the china syndrome, about a nuclear reactor accident cover-ups was released

http://www.imdb.com/title/tt0078966/

so lots of people where left "remembering" the movie and not the real event.

if the movie had come out AFTER, we would be like france in regards to having most of our power supplied by clean nuclear energy today.


RE: come on 1MW
By delphinus100 on 10/8/2009 4:19:47 AM , Rating: 2
Sometimes that just happens.

'Marooned' (1970) was in theaters when the real Apollo 13 happened.

'Spacecamp' (which even made explicit reference to a Shuttle SRB failure) happened to be about the same time as Challenger...


RE: come on 1MW
By Alexvrb on 10/30/2009 1:40:03 AM , Rating: 2
I blame the Fae.


RE: come on 1MW
By Shadowself on 10/8/2009 7:57:45 PM , Rating: 2
We have. Only the public does not know it.

There actually exists a process through the U.S. government whereby a commercial company can launch and operate a nuclear reactor in space. True, there are many hoops to jump through (99% of them justified), but it can be done.


RE: come on 1MW
By SpaceJumper on 10/7/2009 3:11:08 PM , Rating: 3
A human trip to Mars in 39 days requires ten of the 200kW VASIMR engines. This engine is so fast that it will be able explore the edge of our solar system and beyond.
VASIMR is pretty cool and hot at the same time.


RE: come on 1MW
By mmcdonalataocdotgov on 10/9/2009 7:27:21 AM , Rating: 2
Report from Mars Capsule: Mission Control, we passed Mars at 150000 m/s. Ooops, I guess we forgot to decelerate.


RE: come on 1MW
By MrPoletski on 10/12/2009 6:22:34 AM , Rating: 2
how you gonna boost it up with nuclear?

Just a crazy sci-fi Idea that we couldn't possibly do right now, but maybe int he future...

Fusion reactor providing power for the craft, tap off the resultant helium gas left over and use that as thrust via this engine. It'll already be superheated and depending on your fusion rate, could produce a LOT of fuel.

Great thing is though, the higher your fusion rate, the more fuel you have and the more power you have to subsequently heat the expelled helium further.


Star Trek...
By ChristopherO on 10/7/2009 2:20:06 PM , Rating: 3
I read stories like this, and I laugh that all the contributing physicists to Star Trek are asked, "How would we solve this problem?" They usually get it right, and some number of years later we figure out how to solve the engineering challenges for the solutions they daydreamed about decades ago. In most sci-fi the sub-light drive systems are basically the same thing as the VASIMR using plasma for propulsion. (Assuming a few hundred years of progress, and a lot of dramatic license)

Still, what I find more humbling is how much we don't know that we constantly discover. There's always a better way of doing something. A lot of progress has been made *in space*, but I'm wondering what sort of limits we have for improving traditional chemical boosters. Besides the concept of a space elevator, getting away from Earth is just as costly as it has ever been. We can do more interesting things once we get away from here, but getting away is always the biggest problem. Certainly there are some cheaper boosters for small payloads (space ship one, etc), but we seem stuck in the same rut of paying a lot of money for anything large.




RE: Star Trek...
By kattanna on 10/7/2009 3:39:44 PM , Rating: 2
quote:
In most sci-fi the sub-light drive systems are basically the same thing as the VASIMR using plasma for propulsion


in star trek, our VASIMR engines were being powered by multi GW Fusion reactors, instead of lowly 200Kw levels.

thats some serious orders of magnitude difference. who knows.. if we can get such engines up to such power levels, they might just be strong enough to take something into orbit as well.


RE: Star Trek...
By jeff834 on 10/7/2009 9:49:00 PM , Rating: 2
Antimatter not fusion.


RE: Star Trek...
By acer905 on 10/8/2009 12:18:00 AM , Rating: 3
Actually, only the warp core uses an antimatter reaction, the impulse engines use their own fusion reactors to generate the electrical needs for the fusion rockets to function

http://memory-alpha.org/en/wiki/Impulse_engine
&
http://memory-alpha.org/en/wiki/Impulse_reactor

Additionally, it has been assumed that the first vessels to travel at warp speed (i.e. The Phoenix) used fusion reactors to produce the energy needed, but it was abandoned when M/Am was finally perfected and was found to be more efficient


RE: Star Trek...
By lightfoot on 10/8/2009 5:46:26 PM , Rating: 2
Spoken as though it were fact.

The sign of a true Trek geek. :)


By EricR on 10/7/2009 4:30:36 PM , Rating: 4
The article states:
quote:
The rocket is capable of long burns, with its long term goal being to produce enough sustained thrust and impulse to reach Mars in under three months.

Does this mean a high speed fly-by, or does the three months include time to slow down too?

MozeeToby clarifies with:
quote:
...The practical upshot of all that is very slow acceleration but a very high top speed...

Does anyone know how slow – when compared to a current chemical rocket engine – is the "very slow acceleration" of this engine?

I ask because, the slower the rate of change in velocity, the less time you'll benefit from this engine's high top speed.

You're not going to catch a Mars orbit at 150,000 m/s.

Could this be a case of a month or more increasing velocity, only to have to turn the ship around and start decreasing velocity shortly thereafter?

Maybe a combination – VASIMR to get you there along with the high thrust of a chemical engine to slow you down upon arrival?




By jdietz on 10/7/2009 6:49:18 PM , Rating: 3
If you think about how a robot end effector works, it speeds up until it's halfway to the destination, then begins to slow down. This could work similarly if they have a thrust reverser. Slowing down will happen when they are a little over halfway there.


By PrinceGaz on 10/7/2009 7:26:14 PM , Rating: 2
quote:
Maybe a combination – VASIMR to get you there along with the high thrust of a chemical engine to slow you down upon arrival?


Ignoring the weight of the fuels used, it doesn't matter whether you use the chemical engine to quickly slow you down upon arrival, or to instead quickly speed you up when departing, then using the plasma drive for the rest of the journey; the end result is the same.

Given that the chemical rocket uses heavier fuel, you'd be better off getting rid of that at the start, then using the plasma drive for the rest of the journey (you don't want to have the plasma drive accelerating all the chemical fuel for the duration of the journey). In fact you'd be better off getting rid of the chemical engine altogether except for landing, and using the plasma drive to accelerate for the first half of the journey and decelerate for the second half (give or take any difference in the velocity required at the start and end of the journey under plasma power).


By Shadowself on 10/8/2009 8:10:01 PM , Rating: 2
What people are forgetting is the purpose of the VASIMR.

If a VASIMR engine is designed properly...
When in high specific impulse (Isp) mode the thrust is very low, but you get a lot of delta V out of the engine because of very low thrust, very high velocity effluents and thus great propellant efficiency. Conversely, a VASIMR engine can cut back on the specific impulse and radically increase the thrust -- though with a required huge drop in propellant efficiency.

Thus in situations where you need high thrust (deep in the gravity well for example) you can have it even though it is not very propellant efficient because of the low Isp. As you get out of the gravity well and get on toward interplanetary space (or farther) you can rev it up to a very high specific impulse and become very, very propellant efficient -- and still accelerate, though slowly.

It's kind of like having a car that is a gas guzzling race car off the line but can switch to an extremely fuel efficient engine once you get far down the track -- and keep accelerating (though much less slowly).


Space only
By nafhan on 10/7/2009 9:37:29 AM , Rating: 3
quote:
As a result of its reliance on chemical boosters, the cost of flying a single pound into space aboard the space Shuttle to approximately $5,000 to $6,000
VASIMR (like other ion engines) will only operate once the vehicle is in space. The cost to get something into space won't be affected.




RE: Space only
By Seemonkeyscanfly on 10/7/2009 10:02:42 AM , Rating: 2
I figured out that it would be around $1,375,000 to send me to space. As fun as that would be, I'm not sure I'd spend that much on myself for one trip. I'd have to think about it for a while. However, if any one has an extra $1.4 million...


RE: Space only
By nafhan on 10/7/2009 10:10:17 AM , Rating: 5
If you lose 50 pounds, you'll save 250k to 300k dollars on your proposed trip to space. That's some good incentive to lose weight! I'm going on a diet, uhm, after lunch.


Corrections and info
By randomly on 10/7/2009 1:28:44 PM , Rating: 2
It's currently about 65% efficient.

Plasmas are created by high temperatures, not by low pressure (shame on you Jason Mick)

It will be the highest powered ELECTRIC rocket engine in space, it is a tiny fraction of the power of most upper stage chemical engines.

The ISS is reboosted to make up for atmospheric drag losses that constantly lower the stations altitude as Mr. Diaz is quoted in the previous sentence. Your following statement that the ISS requires reboost to dock with the space shuttle or progress is FALSE. Shame on you again Jason. Don't you even pay attention to what the people you are quoting are saying?

The major advantages of VASIMR over other electric rocket engines such as Hall thrusters or Electrostatic grid thrusters are that it can scale to very high power levels (given a high power energy source such as a nuclear reactor), and that the plasma is contained and directed purely by magnetic fields so there are no material erosion problems that plague other electric rocket engines. It can also use a wide variety of reaction mass materials (fuels) and the specific impulse (exhaust velocity) can be varied from about 3000 to 30,000 sec.




RE: Corrections and info
By JediJeb on 10/7/2009 4:03:42 PM , Rating: 2
I noticed that Nitrogen was left off the list of gasses used to form plasma. In the late 80s when I was in college the only gasses listed as being used for Plasma Spectrometers was Argon and Nitrogen. Argon is currently the one used because it requires less power to form the Plasma. Also plasmas do not have to be at 10,000 degrees, there are currently many experiments done with room temperature plasmas, but those would not produce much thrust so not applicable for engines, but they are looking at them for shielding purposes, since cool plasma ( the solar wind) is what shields us from much of the cosmic rays entering the solar system.


RE: Corrections and info
By geddarkstorm on 10/8/2009 12:38:39 PM , Rating: 2
quote:
Plasmas are created by high temperatures, not by low pressure (shame on you Jason Mick)


Really? I don't remember fluorescent light bulbs getting that hot ;). Lowering the pressure decreases the amount of heat/energy needed to turn a gas into plasma. Jason is quite right.


Proofread
By Mclendo06 on 10/8/2009 2:29:30 PM , Rating: 2
Don't get me wrong - I love reading DailyTech, and I can generally overlook the occasional typo, but when I hit three in the first paragraph it just grates on me. Honestly, the first two paragraphs read as through they were copied from a Google translation.

I will say the article improved considerably after the first two paragraphs, though.




RE: Proofread
By gfxBill on 10/8/2009 9:13:18 PM , Rating: 2
++ Had the same thought. Much of the article feels like it reads at a 10 year old level too.


RE: Proofread
By mrteddyears on 10/9/2009 6:05:14 AM , Rating: 2
Why dont you guys get of your backsides and setup your own site if you feel its that bad.


Hypothetical question
By NullSubroutine on 10/9/2009 5:58:34 PM , Rating: 2
So this thing only works with solar energy, but continually gets faster right?

How fast could the vehicle get with a lot of "fuel" and simply flew around the sun for several years then did a gravity sling shot out of the solar system?

I guess what I am getting at is if we can put something like this in orbit around the sun continually gaining speed, then if it left solar orbit it could get to a nearby start system faster than if you just sent it straight there, correct?




RE: Hypothetical question
By blowfish on 10/12/2009 10:26:32 PM , Rating: 2
I guess what I am getting at is if we can put something like this in orbit around the sun continually gaining speed, then if it left solar orbit it could get to a nearby start system faster than if you just sent it straight there, correct?

Absolutely correct! Here on Earth, it's the same. I can get my daughter to school faster by driving round the block a few times, building up speed with each orbit, then hurtling down the main road, decelerating of course with a few laps of the school parking lot upon arrival. The school doesn't like it, but they can't argue with the laws of physics.


WITH SUCH GReAT POWAH
By scrapsma54 on 10/7/2009 11:14:14 AM , Rating: 3
Helghan will prevail with its Electrifying technology!




Official News Release
FYI
By drewsup on 10/8/2009 2:35:07 PM , Rating: 2
5 Newtons = 1.12 pound of thrust.

Sounds hardly eye popping, but seeings how the current ion drives produce the equivalent force a sheet of paper resting on your hand , it's a freaking HUGE advancement.




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