NASA’s Psyche spacecraft performed a gravity assist maneuver around Mars on May 15, using the planet’s gravitational pull to adjust its trajectory toward the metal-rich asteroid Psyche, while simultaneously testing its scientific instruments.
The Psyche spacecraft, launched in 2023, executed a close flyby of Mars on May 15, passing within 2,864 miles (4,609 kilometers) of the planet’s surface. This maneuver, designed to slingshot the probe toward its target asteroid, also served as a test of the spacecraft’s scientific instruments. The mission’s goal is to study the metal-rich asteroid Psyche, believed to be the exposed core of a former planet, but the Mars encounter provided an opportunity to validate the spacecraft’s capabilities before its 2029 arrival.
A Gravity Assist with Scientific Payoff
The flyby was a calculated step in Psyche’s journey. By leveraging Mars’ gravity, the spacecraft gained velocity without burning a drop of fuel, a technique common in deep-space missions. This gravity assist was years in the making, and the navigation team nailed it — Psyche flew by Mars on exactly the trajectory we needed to set us on a path to rendezvous with the asteroid in the summer of 2029,
said Bob Mase, Psyche’s project manager at NASA’s Jet Propulsion Laboratory (JPL).
The mission team used the month-long approach to test all three of Psyche’s scientific instruments: the gamma-ray and neutron spectrometer, the magnetometer, and the multispectral imager. We didn’t anticipate big discoveries, given how extensively the planet has been studied, but we did complement Mars science with the data we collected through Psyche’s unique perspective,
said Lindy Elkins-Tanton, who leads the mission and directs the Space Sciences Laboratory at the University of California, Berkeley.
Neutrons, Magnetic Fields, and a Crimson Crescent
While gamma rays from Mars were too faint to detect, the instrument’s performance confirmed its readiness for the asteroid.
The multispectral imager captured a stunning time-lapse of Mars, starting as a thin crescent with just 4 percent of its disk illuminated. As the spacecraft closed in, the camera documented windblown craters, the south polar ice cap, and the double-ringed Huygens crater. The imager performed brilliantly, delivering some rarely seen views of the Red Planet,
said Jim Bell, the imager lead at Arizona State University.
A Unique Perspective on Mars
The Psyche team also used the flyby to test its ability to detect small celestial bodies, a skill critical for searching for moonlets around the asteroid Psyche. During the encounter, the spacecraft spotted Mars’ moons, Phobos and Deimos, from a distance. We were also able to fully test its calibration and sensitivity to scattered light, including picking out the Martian moons Phobos and Deimos from very far away as a part of a practice for the satellite search that we’ll use at the asteroid Psyche to look for any moonlets there,
said Jim Bell.
ESA’s Mars Express mission coordinated with Psyche to capture the same region of Mars from different angles. The two spacecraft imaged Noachis Terra, an ancient Martian surface, with Psyche’s camera taking a shot 1 hour and 50 minutes after Mars Express. While the images differ in resolution and perspective, the comparison could help calibrate Psyche’s instruments for future asteroid studies.
The Road to Psyche
With the Mars flyby complete, Psyche remains on course for its 2029 rendezvous with the asteroid. The mission’s success hinges on the instruments’ performance, which has now been validated in a real-world scenario.
The encounter also underscored the value of planetary flybys as opportunities for instrument testing. For the Psyche team, the Mars flyby was more than a trajectory adjustment — it was a glimpse of the scientific potential that awaits at the asteroid.
As the spacecraft continues its journey, the data collected during the Mars encounter will inform future studies of the asteroid’s composition and magnetic field. For now, the Red Planet’s fleeting appearance in Psyche’s cameras serves as a reminder of the intricate planning and engineering required to explore the far reaches of the solar system.
Worth a look
