NASA Psyche Spacecraft Switches to Backup Fuel System After Valve Malfunction

NASA’s Psyche spacecraft has successfully switched to its backup fuel line after engineers identified a mechanical valve failure that threatened the mission’s journey to a metal-rich asteroid. The spacecraft, now 628 million miles from Earth, experienced a significant pressure drop in its xenon propulsion system that forced mission controllers to shut down its electric thrusters for nearly two months.

The trouble began on April 1, when sensors detected pressure dropping from 36 pounds per square inch to just 26 psi in the fuel line feeding xenon gas to the spacecraft’s four electric thrusters. This 28% pressure loss triggered automatic safety protocols that powered down the propulsion system, leaving the spacecraft to coast through space on momentum alone.

Xenon Propulsion System Under Scrutiny

The Psyche mission relies on solar electric propulsion, a technology that converts sunlight into electrical energy to power thrusters that expel charged xenon atoms. Unlike traditional chemical rockets that provide massive thrust for short periods, these ion thrusters generate gentle but continuous acceleration over months and years.

Through extensive diagnostic testing, NASA engineers determined that a component inside one of the propellant valves had failed, creating an obstruction that blocked xenon flow. The valve mechanism, designed to open and close to manage fuel flow, appears to have suffered a mechanical breakdown that engineers couldn’t repair remotely.

Backup Systems Save the Mission

Fortunately, mission planners had anticipated such problems. The spacecraft carries two identical propellant lines – a primary system and a complete backup. After weeks of analysis and testing, engineers successfully commanded the spacecraft to switch to its redundant fuel line.

The backup system is now operating as expected, and mission controllers plan to restart the thrusters by mid-June. To prevent similar issues, engineers will keep the backup line’s valve permanently open, eliminating the mechanical cycling that may have contributed to the original failure.

Key Mission Timeline Remains Intact

Despite the two-month delay, Psyche remains on track for its planned arrival at asteroid 16 Psyche in August 2029. The mission timeline included sufficient flexibility to accommodate such technical challenges. Here’s what lies ahead:

• Mid-June 2025: Thrusters resume operation
• May 2026: Mars gravity assist maneuver
• August 2029: Arrival at asteroid Psyche

The Mars flyby represents a critical milestone, as the spacecraft will use the Red Planet’s gravity as a slingshot to accelerate toward the main asteroid belt between Mars and Jupiter. This gravitational assist technique allows missions to reach distant targets without carrying additional fuel.

Metal World Awaits

What makes this mission particularly intriguing is its destination. Asteroid 16 Psyche appears to be composed largely of iron and nickel, possibly the exposed core of a failed planet. Scientists believe studying this metal-rich world could provide insights into how planetary cores form and evolve.

The spacecraft launched from Kennedy Space Center in October 2023, beginning a journey that will span nearly six years. While the recent propulsion issues created uncertainty, the successful switch to backup systems demonstrates the value of redundant engineering in deep space missions.

Could this valve failure pattern affect other spacecraft using similar technology? NASA hasn’t indicated whether the issue might impact other missions, but the agency’s methodical approach to diagnosing and resolving the problem provides valuable data for future electric propulsion systems.

The Psyche mission continues to pioneer advanced technologies, including NASA’s first test of laser communications in deep space. As the spacecraft resumes its powered flight toward the asteroid belt, it carries with it not just scientific instruments, but also lessons learned about the reliability of next-generation propulsion systems.