Ion Engine Could One Day Power 39-Day Trips to Mars

There’s a growing chorus of calls to send astronauts to Mars rather than the moon, but critics point out that such trips would be long and gruelling, taking about six months to reach the Red Planet. But now, researchers are testing a powerful new ion engine that could one day shorten the journey to just 39 days. Traditional rockets burn chemical fuel to produce thrust. Most of that fuel is used up in the initial push off the Earth’s surface, so the rockets tend to coast most of the time they’re in space. Ion engines, on the other hand, accelerate electrically charged atoms, or ions, through an electric field, thereby pushing the spacecraft in the opposite direction. They provide much less thrust at a given moment than do chemical rockets, which means they can’t break free of the Earth’s gravity on their own