NASA’s Psyche spacecraft began nearly continuous electric propulsion on September 28, 2026, following its Mars gravity assist. An October 22 mission update says the spacecraft is now thrusting through most of its cruise toward the metal-rich asteroid Psyche, with arrival planned for summer 2029.
The mission expects its propulsion system to operate nearly 90% of the remaining travel time. Psyche has four Hall-effect thrusters but operates one at a time. Solar arrays supply electricity, and xenon provides the material expelled to generate thrust.
Electric propulsion separates the energy source from the propellant. Sunlight becomes electrical power in the arrays. Inside a Hall thruster, xenon is ionized, producing electrically charged atoms, which electromagnetic fields accelerate out of the engine. Their departure produces a force on the spacecraft in the opposite direction.
NASA’s Jet Propulsion Laboratory explains the propulsion system: the resulting thrust is small but can be applied for long periods. A chemical rocket supplies much larger forces for launch and short maneuvers. Psyche’s electric system is suited to accumulating velocity changes during a journey lasting years, after the launch vehicle has already placed it on an interplanetary trajectory.
The current system delivers up to 250 millinewtons of thrust. NASA expects full-power operation for roughly three months after the update, followed by a gradual reduction toward half power as the spacecraft travels farther from the Sun. Less sunlight means less electrical power available for propulsion.
The thrusters also produce a small twisting effect called swirl torque. Reaction wheels absorb the resulting angular momentum. Periodically, controllers stop the main thrust, change orientation, and briefly operate another thruster at low power to unload the wheels.
The destination is a metal-rich asteroid that may preserve material from the interior of an early planetary body. That origin remains a scientific hypothesis to be investigated. New Space Economy’s account of the Psyche mission explains why the object is relevant to planetary interiors: spacecraft cannot directly examine Earth’s metallic core, but an exposed remnant elsewhere could provide evidence of related formation processes.
The spacecraft’s instruments will investigate the asteroid from orbit. For the current cruise, the operational task is sustained, power-managed thrust that brings Psyche to its planned 2029 encounter.
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