The VASMIR VX-200 is touted as the most powerful spacecraft engine ever. It's capable of 0.5 N thrust and recently broke "the 200kW maximum power milestone." Videos after the break.
The VASIMR VX-200 has two electromagnetic stages: The first one runs at 32kW and generates plasma from Argon gas, while the second one uses the plasma to output an additional 168kW.[via Gizmodo]
