NASA's Psyche spacecraft performed its closest approach to Mars today, 15 May 2026, passing just 4,500 kilometres (2,800 miles) from the planet's surface at a speed of 12,333 miles per hour (19,848 kilometres per hour).¹² The flyby is a critical milestone in Psyche's long journey to the metal-rich asteroid of the same name, using Mars's gravitational pull to bend the spacecraft's trajectory and add speed without burning propellant — a technique known as a gravity assist.³⁴

Launched on 13 October 2023 from NASA's Kennedy Space Center, Psyche relies on a solar-electric propulsion system, using the inert gas xenon as propellant and building speed gradually over its multi-year journey rather than in a single powerful burn.⁸ Swinging around Mars allows mission planners to harvest gravitational energy from the planet for free, preserving the spacecraft's xenon supply for the more precise manoeuvres required when it eventually arrives at asteroid Psyche in late 2029.³⁶

What the spacecraft is doing during the flyby

Rather than simply threading past Mars as a navigation waypoint, the Psyche team is treating the flyby as a scientific opportunity. Mission engineers plan to use the spacecraft's multispectral imager to capture thousands of observations of Mars during the approach and departure, providing a real-world test of the instrument's performance against a large, well-characterised target.¹² "This is our first opportunity in flight to calibrate Psyche's imager with something bigger than a few pixels," the mission team noted ahead of the encounter.¹

The spacecraft's other instruments are also actively collecting data. Psyche's magnetometer is expected to detect the Martian magnetic field redirecting charged particles from the Sun — an indirect observation that will help validate the instrument's sensitivity before it must characterise the magnetic environment of the asteroid, which scientists believe may be a remnant of an ancient planetary core.¹⁴ The gamma-ray and neutron spectrometer will monitor how cosmic ray flux — highly energetic subatomic particles from interstellar space — changes as the spacecraft sweeps through the Martian environment.¹

A coordinated observation campaign

The Psyche flyby is not a solo event. Several existing Mars missions have been recruited to observe the encounter from their orbits and the Martian surface, providing complementary data and helping Psyche's navigation team refine the spacecraft's precise position in space.¹⁷ NASA's Mars Reconnaissance Orbiter and Mars Odyssey orbiter are both participating, as are the Curiosity and Perseverance surface rovers. ESA's Mars Express and ExoMars Trace Gas Orbiter are also contributing observations.¹

This degree of coordination across multiple missions is unusual and reflects both the scientific value of the encounter and the operational complexity of a spacecraft moving at more than 12,000 miles per hour through a region already populated with active hardware.⁵⁹ Mission controllers added the flyby event to NASA's Eyes on the Solar System public visualisation tool on 14 May, allowing members of the public to track the spacecraft's trajectory in real time.¹⁰

The destination: asteroid Psyche

Asteroid 16 Psyche, Psyche's destination, is one of the most scientifically intriguing objects in the solar system. Located in the main asteroid belt between Mars and Jupiter, it is thought to be predominantly metallic — possibly an exposed planetary core left over from an early solar system collision that stripped away the surrounding rocky mantle.³⁶ If confirmed, it would be the first time humanity has observed a planetary core directly, offering a window into the kind of material that makes up Earth's own inaccessible interior.⁴

No spacecraft has ever orbited a metallic asteroid, and Psyche's science instruments are designed specifically for an environment unlike anything previously studied up close. After today's Mars encounter adjusts its trajectory, the spacecraft will continue its outward journey for another three-and-a-half years before entering orbit around the asteroid in late 2029 and beginning its formal science mission.⁸⁶

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NASA's Psyche Spacecraft Swings Past Mars Today at 12,333 mph in Rare Gravity-Assist Manoeuvre