New ion engine could reach Mars in 39 days

Last week, as the world celebrated the first lunar landing, Apollo 11 astronauts Buzz Aldrin and Michael Collins both called for NASA to make Mars its next goal. But the chemical propulsion system that took them to the moon would take six months, at least, to get a man to Mars and cost hundreds of billions of dollars. However, a new ion plasma rocket being developed by another former astronaut, Franklin Chang-Diaz, could potentially reach Mars in just 39 days using a fraction of the fuel.

The problem with traditional rockets is that they’re terribly inefficient. About 90% of a mission’s initial weight is fuel, most of which is burned up escaping earth’s gravitational pull. After that, a traditional rocket could only slowly coast to Mars. Very slowly. Scientists describe rocket efficiency in terms of specific impulse, which is a rough measure of how fast fuel is ejected out of the back of the rocket. A chemical rocket has a relatively low specific impulse of 450 seconds - in other words, it gets one pound of thrust from one pound of fuel for 450 seconds.

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