NASA engineers have tested a next-generation lithium-plasma electric propulsion system that reached 120 kilowatts, a new U.S. record and about 25 times the power of the electric thrusters on NASA's Psyche spacecraft. "Designing and building these thrusters over the last couple of years has been a long lead-up to this first test," said James Polk, who is a senior research scientist at NASA Jet Propulsion Laboratory. "It's a huge moment for us because we not only showed the thruster works, but we also hit the power levels we were targeting. And we know we have a good testbed to begin addressing the challenges to scaling up." Universe Today reports: While 120 kilowatts is a new record, NASA estimates it a future human mission to Mars will require 2 to 4 megawatts of power consisting of several thrusters and requiring more than 23,000 hours (958 days/2.6 years) of operation.…