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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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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).


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