NASA’s NEXT ion thruster sets new world record


Ion propulsion has come a long way from the 1960s when it was an engineering curiosity with a cool Star Trek name. Instead of burning fuel, an ion thruster gets its electrical power from solar panels or a nuclear power source. It uses this electricity to ionize molecules (in NEXT’s case, xenon) and then a cathode to accelerate them electrostatically. As the molecules shoot out the back of the engine, they create thrust.

That sounds simple, but the amount of thrust is tiny – about the equivalent of the weight of a coin resting on a table. Where the ion thruster has it over chemical rockets is, firstly, in terms of efficiency – ion thrusters are 10 to 12 times as fuel efficient as chemical rockets. Secondly, an ion thruster can run for a much longer period of time. Where chemical rockets burn for minutes, ion thrusters can burn for thousands of hours, which allows that tiny amount of thrust to build up into speeds needed for deep space missions…

Its current record of 43,000 hours is the equivalent of nearly five years of continuous operation while consuming only 770 kg of xenon propellant. The NEXT engine would provide 30 million-newton-seconds of total impulse to a spacecraft. What this means in simple terms is that the NEXT engine can make a spacecraft go (eventually) very far and very fast.

The nicest thing about a constant rate of acceleration is that even a little bit over a very long period of time gets you traveling unbelievably fast.

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  1. keaneo

    Anyone out there for the maths to calculate speed after a year or two or more? I’ll go wander the NASA site and see what they say.

    • keaneo

      Nothing reasonable for my poor non-astro-maths consciousness.

      Heavy discussions on efficiency which seems to approach 54% – which impresses the heck out of me.

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