Lochsteppe: debug: It doesn't really seem like that kind of life span would actually be necessary. Once you're in zero G wouldn't inertia pretty much keep you going? You would just need thrusters for course changes, right?TFA talks about its use for scooting around the solar system, mining asteroids for crystals to make Sinibombs & such. Doesn't sound like they plan to use it for a straight shot to the next star system right away.
DubtodaIll: Build a track long enough and theoretically there's almost no limit to the speed you can reach, escape velocity would be easily attainable.
DubtodaIll: The article didn't mention what kind if fuel the ion engine use but I'm just guessing its considerably lighter than rocket fuel which is why it would be optimal for the mag lev track.
Ishkur: JesseL: With a 1000Kg starting mass and 230Kg final mass, plugging the numbers into the Rocket Equation yields something more like 333,500 km/s for the final velocity.That's faster than the speed of light.You may have misplaced a decimal or something.
Flatus: It doesn't matter if they test it for five thousand years, this Administration doesn't give a crap about space exploration and we're not going anywhere meaningful for a long, long time.
debug: It doesn't really seem like that kind of life span would actually be necessary. Once you're in zero G wouldn't inertia pretty much keep you going? You would just need thrusters for course changes, right?
UberDave: Someone do the math. I'm hastily (and probably incorrectly) getting 30,000 k/s for that thrust and run time given 1000kg in mass (770 for fuel plus me rounding it up). I thought it would be way faster.
With such puny thrust, a NEXT-based ion drive would need to run for 10,000 hours - just over a year - to reach a suitable speed for space travel. Dawn, a NASA probe that's powered by previous-generation NSTAR ion thrusters, accelerated from 0 to 60 mph in four days. As a corollary, ion thrusters only work at all because of the near-vacuum of space; if there was any friction at all, like here on Earth, an ion drive would be useless. The good news, though, is that the (eventual) max speed of a spacecraft propelled by an ion drive is in the region of 200,000 miles per hour (321,000 kph).
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