Ion Engines

Ad Astra's Variable Specifc Impulse Magnetoplasma Rocket (VASIMR)

 

It seems that in the long run, space exploration or travel will never work with the speeds we have now. Rocket engines using chemical fuels just don't cut it when it comes to traveling far, going to other planets that would take years to get to. Ion engines are not that new of a concept, the idea's been around since the beginning of the 20th century.


While ion engines may not provide nearly as much power as traditional chemical engines, they are extremely efficient, ten times more so than chemical engines. Also, even with the small amounts of power ion thrusters can put out, they can be on continually, unlike a regular propulsion system which shuts off and lets the spacecraft coast. With ion engines, the spacecraft would constantly be accelerating; no matter how slowly, it will always be getting faster and faster. This with the fact that so much less fuel is needed because of the efficiency, ion engines may be the thrusters of the future.

However, as most people point out, the power provided by ion thrusters is just too small for big rockets and big missions to fly on. Traditionally, ion thrusters work by firing electrons at xenon gas, turning them into a positive ion. The ions are attracted to a negatively charged grid, then a second grid positively charged repels the ions out of the rocket, providing thrust. The company Ad Astra, featured on PopSci, made the VASIMR engine, which shoots radio waves at argon, providing the same effect but much higher thrust. If a nuclear reactor were used to power the VASIMR's engines, providing megawatts of power compared to NASA's kilowatts, the engine could be used to theoretically get humans to Mars in 39 days.