• Question: How much time would a spacecraft using ion propulsion take to get to Mars? Can the technology be used for a manned mission to Mars?

    Asked by to Aimee, Chris, Dave, Greig, Laurence on 19 Jun 2014. This question was also asked by .
    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 19 Jun 2014:

      How long it takes to get to Mars mainly depends on 2 things.
      First, what is the alignment of the two planets with respect to each other. Mars and the Earth are not always synchronized in their relative orbits, sometimes they are very far form each other, sometimes much closer. About every two years, they are as at their point of closest approach (that’s called ‘opposition’).
      Second, it depends on how much fuel you are willing to burn. The more fuel you burn, the faster you’ll get there. The cool thing with space is that once you’ve reach the escape velocity from Earth, there is no air is space to slow you down, so you don’t need to constantly power the engine like a car or a plane needs to on Earth, you can just ‘drift’ to Mars (well, you DO need to constantly adjust your trajectory, to make sure you won’t miss Mars…!!)

      Given those two things, the total journey time from Earth to Mars takes between 150 to 300 days.

      Ion propulsion have been used for the first time in a deep space mission in 1998, in Deep Space 1, and it showed it was possible to use that for long term missions.

      Since then, the main deep space exploration mission to use it (I think) was Dawn. It took off in Sept 2007, and reached Mars in Feb 2009, so it took a bit less than a year and a half. It didn’t stay around Mars though, because that wasn’t its main mission. It will go and explore Ceres, and it’s planned it’ll get there is 2015.

      I think it’d be possible to use ion thrusters technology to bring humans on Mars, but i’m really not an expert! maybe the other ones know more about this?

    • Photo: Greig Cowan

      Greig Cowan answered on 19 Jun 2014:

      Hi 12allep! It depends on how powerful the ion engine was, but we are probably talking about at least 6 months. One of the issues to deal with is that once you are up to speed, you probably will have to turn the space-ship around to start slowing it down. Otherwise you might be in danger of slamming right into Mars (or shooting right past it)!

    • Photo: Dave Jones

      Dave Jones answered on 20 Jun 2014:

      Ion propulsion has some benefits over the classical chemicals rockets, but in terms of manned space flight they are mostly disadvantages. The good thing about ion thrusters is that they can last for a long time, which would be good for a long space flight like one to Mars. The main bad thing is that they are not particularly powerful, meaning that for take off and landing (where they have to overcome the force of gravity) they just aren’t powerful enough. This is why, in general, any rocket/satellite with ion thrusters also has a classical chemical rocket engine. The ion thrusters are good for keeping the craft stable while in space, maybe even making small adjustments, but for the entire mission, you’d need to also use chemical rockets like the ones NASA has used for all it’s manned space missions.

    • Photo: Aimee Hopper

      Aimee Hopper answered on 21 Jun 2014:

      Ion propulsion isn’t very effective on the earth, as it doesn’t produce enough thrust on the surface of the Earth to overcome the forces of gravity and air resistance (drag). Also, being ions, it would cause a LOT of damage to whatever got hit in the process.

      It’s useful in space because there is nothing to ionise (give or take), gravity is much much weaker and there’s no air resistance to fight against.

      Kerbal Space Program is a great game to play around with this sort of thing :D!

      And we do have the technology to get humans to Mars, we just can’t get them back!

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