NASA has switched on electric Hall motors – aka ion engines – on the Psyche spacecraft. The spacecraft is currently heading toward a metal-rich asteroid in the asteroid belt beyond Mars. The agency reports that Psyche is in “full cruise” mode. This was reported by The Verge.

It is expected to reach its target by 2029 and will orbit the asteroid for another two years, making observations and sending data back to NASA.

The ion engine is the “well-forgotten old one”. The agency has been working on this technology since before American astronauts first flew to the moon, testing its first ion engine in 1964.

NASA first used an ion engine as the main propulsion system for the Deep Space 1 mission in 1998. In 2007, Dawn became the “first exclusively scientific” mission to use ion engines, and the spacecraft flew until it ran out of hydrazine, the fuel used for the orientation thrusters. Without it, it could not return and maintain communication with NASA.


Hall thrusters have no moving parts, but instead generate thrust by exciting xenon particles and pushing them out of the thruster. More information about ion propulsion can be found here.

Also, Dan Goebel, chief engineer of the Psyche project, told in his blog the difference between electric space engines.

Ion engines are not powerful enough to launch a rocket from Earth, but they can still reach very high speeds over time. Right now, according to NASA, Psyche is traveling at 37.1 km/s (23 miles), or about 135,184 km/h (84,000 miles). Eventually, the vehicle will reach a speed of 199,640 km/h (124,000 miles).

Engines like Psyche’s are generally useful because the lack of moving parts makes them durable and they use less fuel. At the same time, they are lighter and can be used on smaller spacecraft.