This Plasma Engine Could Get Humans To Mars On 100 Million Times Less Fuel

[Fweethawt]

This is sweet.

 

http://www.sciencealert.com/this-plasma-engine-could-get-humans-to-mars-on-100-million-times-less-fuel

[Thought2Much]

Hmmm... at first glance, this looks a lot like the VASIMR concept. I wonder what kind of thrust they would be looking at with this compared with VASIMR. Long specific impulse times and high efficiency are great, but if you can't generate enough thrust, then moving people to Mars would take a looooong time, a problem that the developers of VASIMR are (ultimately) looking to solve.

[bornagainathiest]

Right on the money, T2M..!

 

Hall thrusters may use 100 million times less fuel than other engines, but the price you pay for such fantastic fuel economy is a very low thrust-to-weight ratio.  The graphic on this page says it all. 

 

http://en.wikipedia.org/wiki/Thrust-to-weight_ratio

 

Electrostatic/magnetic engines are much more efficient than chemical or nuclear systems, but just look at their stats..!

They both fall below 10^-4 of 1g.  Great for the low-thrust, long-duration journeys of robot probes, but no good at getting humans quickly to other planets to avoid a prolonged exposure to radiation in deep space.

 

Thanks,

 

BAA.

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You there, Pantheory..? 

 

 

[pantheory]

Right on the money, T2M..!

 

Hall thrusters may use 100 million times less fuel than other engines, but the price you pay for such fantastic fuel economy is a very low thrust-to-weight ratio.  The graphic on this page says it all. 

 

http://en.wikipedia.org/wiki/Thrust-to-weight_ratio

 

Electrostatic/magnetic engines are much more efficient than chemical or nuclear systems, but just look at their stats..!

They both fall below 10^-4 of 1g.  Great for the low-thrust, long-duration journeys of robot probes, but no good at getting humans quickly to other planets to avoid a prolonged exposure to radiation in deep space.

 

Thanks,

 

BAA.

 

You there, Pantheory..? 

 

Yeah, I agree. The weight that must be considered is not just the fuel weight, but the engine weight that is needed to implement this technology would outweigh the extra fuel weight. As a shuttle vehicle going back and forth between Earth and Mars it  might be great, although the development and  production costs for a large craft with such an engine, will probably be much greater than conventional rocketry or other alternatives.

 

At present such an engine is no good at all as a lift engine because of the very low power-to-lift factor. So one would need a lift vehicle first to go from Earth to orbit, then the ion engine could be used for planet shuttling, then the same lift vehicle would need to be used to go down and up from Mars, then down to Earth again.

 

Because a much larger engine would be required than what presently exists, I don't see this engine as being competitive to alternatives in the foreseeable future except for robotic missions using existing designs.