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One big note up front! Electric propulsion engines are usually not specific impulse limited! Your power source mass dwarfs the reaction mass ("fuel") really qu
by Gravityloss 11y ago
One big note up front! Electric propulsion engines are usually not specific impulse limited!
Your power source mass dwarfs the reaction mass ("fuel") really quickly.
Basically, for equivalent thrust, with twice the specific impulse you require half the fuel but double the power.
So often with electric propulsion you get a better, lower spacecraft mass by using lower specific impulse! This means more reaction mass but smaller solar panels / power electronics.
That's why things like hall thrusters are used, with ISP around 1000s compared to 3000 s gridded ion engines.
Maybe for a Venus or Mercury mission where you have plenty of power and need large delta vees...
- Symmetry 11y agoThat just what I was going to say, but probably put better. Another important metric for electric propulsion is how reliable they are - that is how long you can run them before they burn out. The fact that they're eroding the cathode intentionally might mean this form of propulsion could do well on that metric but only testing will tell.
- Symmetry 11y agoI guess that means that it would be good for satellite station keeping?
- deleted 11y ago[deleted]
- phkahler 11y agoYep. I was just going to correct them on this: >> In our system the cathode is a cylindrical rod of conducting material that we choose to use as fuel (eg magnesium, vanadium etc). This is wrong. They are using it as propellant, not fuel.
- Gravityloss 11y agoWhat is great is they can use other reaction mass than Xenon, which is very rare. And if it's a solid right in the electrode, it's potentially very easy to store. Probably limits total mass though so maybe use it for very low acceleration missions where you can use the high isp. Like stationkeeping indeed.