Our Place in Space: VASIMR

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, V is for…


For space enthusiasts and people directly involved in space exploration, VASIMR can be a highly controversial subject.  In some circles, mentioning VASIMR is almost like bringing up abortion or gun control.  VASIMR supporters will tell you that this technology could radically reduce the fuel costs associated with space travel and also cut down the transit times for interplanetary journeys.  The anti-VASIMR crowd will tell you that this technology has been stuck in the research and development phase for four decades now and that it’s time we cut our losses and spend all that R&D money on something else.

VASIMR stands for VAriable Specific Impulse Magnetoplasma Rocket.  Rather than generating thrust through controlled chemical explosions (as traditional rockets do), a VASIMR engine heats up a neutral gas (typically argon or xenon), ionizes that gas, then accelerates the gas using super powerful magnetic fields.  The magnetically accelerated gas shooting out the back of your spaceship will propel your spaceship forward.

The weight of your argon or xenon fuel would be far less than the weight of the liquid oxygen/liquid hydrogen fuel used in most rockets today.  And in theory, VASIMR powered rockets could travel faster than chemically propelled rockets.  We could get to Mars in a matter of weeks rather than months, or get to Jupiter in a matter of months rather than years!  So why aren’t we already using this technology?

The problem, as I understand it, is that it takes a lot of power to ionize argon or xenon gas.  It takes even more power to generate those super powerful magnetic fields.  All the equipment needed to generate that much power is heavy.  Prohibitively heavy.  Whatever advantage VASIMR might offer in terms fuel weight is thoroughly negated by the weight of all the extra equipment you’d need to make the engine work.

The idea for VASIMR was originally pitched in 1977.  The first laboratory experiment was conducted in 1983.  This technology really has been in development now for four decades, and it’s still not ready to fly.

I’m not going to advocate for cutting funding on this research.  Progress has been made over the last forty years.  It’s slow progress, to be sure, but slow progress is still progress, and if VASIMR ever does work as intended, it would be a huge, huge breakthrough for space exploration.  Many things that are not possible for us right now would suddenly become possible.

If it ever works as intended….

Want to Learn More?

As I said, VASIMR can be pretty controversial.  To give you a better sense of that controversy, I’m going to recommend this article by Robert Zubrin (President of the Mars Society), titled “The VASIMR Hoax.”  I’m also going to recommend this response to Zubrin from Ad Astra Rocket Company (the company currently working on VASIMR), titled “Facts About the VASIMR Engine and Its Development.”

17 thoughts on “Our Place in Space: VASIMR

    1. Is it environmentally friendly? That’s another part of the controversy. VASIMR uses argon or xenon propellant, so we’re not burning hydrocarbons. That’s good. Chemical rockets don’t usually use hydrocarbons either, though, so that doesn’t make much of a difference.

      However, to keep the weight down, VASIMR would almost certainly have to be nuclear powered. And so if there’s an accident at launch, we may have to deal with the nuclear fallout afterward.

      Liked by 1 person

      1. I don’t know, maybe when they finally get the thing working, it’ll turn out it doesn’t need nuclear power, or maybe they’ll figure out a way to make it safe by then. I don’t want to be too much of an alarmist about something that’s still deep in the R&D phase.


  1. From what I’ve read, VASIMIR (and similar ion type drives) are best thought of as supplements. They’re low thrust, but can run continuously for weeks or months, gradually accelerating or decelerating. But the low thrust makes it incapable of lifting out of a gravity well. So you still need conventional rocketry for the initial launch and other planetary logistics.

    Not sure if I’d heard about the weight issues before though. There always seems to be something.

    Liked by 1 person

    1. Interesting. I’m pretty sure a lot of these proposed types of propulsion focus on in-space propulsion rather than launch. It seems like VASIMIR is also an in-space propulsion type. I’d be curious to see if we are anywhere near finding more environmentally-friendly launch methods, since that’s something that is quite pressing.

      Liked by 1 person

      1. Interesting. I really only knew about the environmental impact of liquid oxygen/liquid hydrogen, which basically doesn’t hurt the environment at all. Sounds like there are plenty of other propellants in use that are more problematic.

        P.S.: I’m adding “the Devil’s venom” to my list for future Sciency Words posts.

        Liked by 1 person

      2. That was my initial take too. How bad can oxygen and hydrogen be? But having to mix in high powered kerosene, along with solid fuel boosters, makes things a lot less clean. And I knew about hydrazine, but hadn’t heard that the Russians used it in the atmosphere. “Devil’s venom” is a good name.

        Liked by 1 person

    2. I was not aware of that. That clears up some things I read that were kind of confusing to me. I’ve had a hard time researching VASIMR. There are so many strong opinions about it, one way or the other, and I’m never sure where the opinions end and the fact begin.

      Liked by 1 person

      1. I think there were hopes it might be able to produce a lot more thrust than typical ion drives, and it’s very easy to come across descriptions infused with that sentiment, but most of what I’ve seen from actual tests has been a lot more modest. Still, if they could ever make it practical, it might shorten mission times substantially.

        Liked by 1 person

    1. That is a good way to think about it! Space exploration is a multi-generational adventure. Very few of the projects I’ve been talking about will be finished in our lifetime, but if we can get these things started now, future generations will be able to finish them.

      Liked by 1 person

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