NASA's Psyche Mission Gains Speed After Mars Flyby

The NASA Psyche spacecraft successfully completed a critical close approach to Mars on May 15, using the planet's gravitational pull for a significant speed increase and orbital adjustment. This maneuver, a gravity assist, allows the mission to conserve precious onboard propellant and maintain its trajectory toward the asteroid Psyche. The spacecraft is now en route to the main asteroid belt, situated between Mars and Jupiter, where its metallic target awaits. Following the Martian encounter, mission control confirmed Psyche's correct path by analyzing radio signals transmitted to NASA's global Deep Space Network.

"Although we were confident in our calculations and flight plan, monitoring the DSN’s Doppler signal in real time during the flyby was still exciting," stated Don Han, Psyche's navigation lead at NASA’s Jet Propulsion Laboratory in Southern California. "We’ve confirmed that Mars gave the spacecraft a 1,000 mile‑per‑hour boost and shifted its orbital plane by about 1 degree relative to the Sun. We are now on course for arrival at the asteroid Psyche in summer 2029." This successful gravity assist propels the mission forward, reducing the need for extensive fuel consumption on its long journey.

Instruments Calibrated During Martian Encounter

In the days leading up to and during its closest pass by the Red Planet, all of Psyche’s scientific instruments were activated for calibration. This included its advanced imagers, sensitive magnetometers, and its gamma-ray and neutron spectrometer. The encounter provided the mission with an invaluable opportunity to practice operational procedures that will be employed once it reaches the asteroid. As an added benefit, the flyby yielded unique images of Mars from an unusual vantage point. Approaching Mars at a high phase angle, the spacecraft captured images of the planet appearing as a thin crescent, illuminated by sunlight reflecting off its surface.

Observations from the spacecraft’s multispectral imager revealed that the crescent appeared unexpectedly brighter and extended further around the planet’s disk. This phenomenon is attributed to the strong scattering of sunlight through Mars' dusty atmosphere. As Psyche transitioned from observing Mars' nighttime side to its daytime hemisphere, it rapidly captured a series of detailed surface images during its closest approach. "We’ve captured thousands of images of the approach to Mars and of the planet’s surface and atmosphere at close approach," said Jim Bell, the Psyche imager instrument lead at Arizona State University (ASU). "This dataset provides unique and important opportunities for us to calibrate and characterize the performance of the cameras, as well as test the early versions of our image processing tools being developed for use at the asteroid Psyche." Bell, who also leads the Mastcam-Z imaging investigation for NASA's Perseverance Mars rover, explained that calibration imaging of Mars will continue throughout May as the spacecraft moves away.

Complementary data for calibration efforts were also provided by other NASA missions, including the Mars Reconnaissance Orbiter, the 2001 Mars Odyssey orbiter, and the Curiosity rover, alongside the European Space Agency's Mars Express and ExoMars Trace Gas Orbiter. Preliminary calibration measurements from Psyche’s magnetometers may have also detected Mars' bow shock during the flyby. The gamma-ray and neutron spectrometer team is actively gathering data to calibrate its instrument by cross-referencing measurements with the substantial existing body of Martian data.

With Mars now behind it, the Psyche spacecraft will soon recommence operations with its solar-electric propulsion system, charting a direct course to the main asteroid belt. Upon its projected arrival in August 2029, Psyche will enter orbit around the asteroid itself. This celestial body is believed to be a remnant core of a planetesimal, a primordial building block of an early planet. By executing a series of descending and ascending circular orbits around the asteroid, which measures approximately 173 miles (280 kilometers) in diameter at its widest point, the spacecraft will meticulously map its surface and collect vital scientific data. If the asteroid indeed proves to be the metallic heart of an ancient planetesimal, it offers an unprecedented opportunity to study the interior composition of rocky planets, including our own Earth.

"We’ve been anticipating the Mars flyby for years, but now it’s complete. We can thank the Red Planet for giving our spacecraft a critical gravitational slingshot farther into the solar system," commented Lindy Elkins-Tanton, principal investigator for Psyche at the University of California, Berkeley. "Onward to the asteroid Psyche!" The mission, led by ASU, involves JPL for overall management and operations, and Intuitive Machines for the spacecraft chassis. The space-exploration initiative is part of NASA’s Discovery Program.