VASIMR: Replacing chemicals with plasma: easy, affordable, fast and economically rewarding

The single biggest thing preventing us from exploring further and for longer in space is the ability of our rocket engines to take us where we want to go in an efficient manner,” says Dr. Michael Griffin, former head of NASA.

Dr. Griffin was speaking on an amazing video created by Ad Astra, a company founded by former astronaut Dr. Franklin Chang Diaz.

The principal presenter is Dr. Chang Diaz a soft spoken man, a man who lets the power of the truth carry the weight of convincing the listener.

The video makes the case for Ad Astra’s Variable Specific Impulse Magnetoplasma Rocket (VASIMR) by first citing the benefits of an inexpensive rocket engine.

Recalling the role that railroads played in the development of the United States, Dr. Chang makes the point that a similarly inexpensive transportation system would fuel the economic development of space.

But Dr. Chang Diaz points out that chemical rocket engines cannot fill that role for two reasons. First, they can’t be developed to generate much more heat than they do presently. Heat means thrust, lift capacity, speed.

In any event, even if the chemistry could be made to produce more heat, the metal used in the engine components can’t be developed to tolerate much higher temperatures than they do at present.

Chemical rocket engines generate roughly 2,000 degrees of heat.

In comparison Ad Astra aims to create a rocket creating temperatures of 1 million or even 2 million degrees.

“No chemical reaction can do that,” Dr. Chang Diaz says. “So we don’t do chemistry. We use electricity. We go from gas to plasma.”

Ad Astra’s alternative is VASIMR, a plasma engine.

Quoting from the video:

“We inject a propellant, a neutral gas, into the ionization chamber. We launch radio waves at it. Those radio wave convert that gas into a cold plasma. This plasma then proceeds into the booster section, the ion cyclotron resonance. The next step would be to put electrical energy in to superheat the gas in a plasma state, and then accelerate it to the velocities needed for space travel.”

The limits imposed by the ability of chemicals to produce thrust are addressed by the use of plasma.

The limits of metal to deal with heat are addressed by eliminating the need for metal.

Quoting Dr. Chang Diaz, “Our pipe through which the exhaust goes is really a magnetic pipe, an invisible force.”

With these two changes Dr. Chang Diaz concludes that “We have eliminated the most fundamental limit in rocket propulsion which is how hot you can make the exhaust.”

The hotter exhaust translates into incredible performance. A VASIMR powered ship would be ten times faster than current chemical rocket engines. A VASIMR rocket could make the trip to Mars, for example, in just over a month.

In addition to speed VASIMR’s capabilities are game changing at other fundamental levels.

Shorter travel times mean less exposure for crews to harmful radiation and the effects of weightlessness.

Speed helps in another way as Dr. Griffin points out.” If you’re doing scientific research, to be able to get research results in eight or ten years instead of thirty five or forty years is a huge accomplishment”

VASIMR’s fuel cost would be one tenth of the current chemical rocket engines. Dr. Chang Diaz cites a $220 million chemical fuel cost per launch and states that the VASIMR rocket fuel cost would be $20 million. There’s no way to estimate the value to be derived from such an exponential increase in available money.

Another intriguing role Dr. Chang Diaz and his team see for a VASIMR powered space craft is in reducing the risks associated with space debris.V00008

No cost effective way exists currently to deal with the debris in orbit around the Earth. On the video former astronaut Eileen Collins, the first woman commander of a space shuttle flight, talks about the fact that the number one risk to the shuttle and her crew was getting hit by orbiting debris.

The cost associated with a VASIMR powered craft would allow for debris to be intercepted and directed into a decayed orbit for eventual destruction.

NASA is interested in developing VASIMR and awarded Ad Astra a grant to take the next steps in development.

What can’t be captured in a description of the video is the vision that Dr. Chang Diaz and the others exude. While its obvious to everyone that humans are making strides in space exploration, these people see the next steps. They talk about the commercialization of space as if it was a near term event, waiting for the equivalent of a trans-continental railroad to be built.

They talk about humans living and working not just in near earth orbit but throughout the solar system.

They talk about the future as if it were here and now.

It’s a great video and worth the watch.

Here’s the link.