NASA’s Psyche spacecraft is preparing for a close encounter with Mars that will help send it deeper into the solar system on its way to the metal-rich asteroid Psyche. On Friday, May 15, the spacecraft will pass just 2,800 miles (4,500 kilometers) above the Martian surface while traveling about 12,333 mph (19,848 kph). During the flyby, Mars’ gravity will alter Psyche’s path and increase its speed, reducing the amount of propellant needed for the long mission ahead.
Launched on Oct. 13, 2023, Psyche uses a solar-electric propulsion system powered by xenon gas. Instead of relying entirely on its thrusters, mission planners are taking advantage of Mars’ gravitational pull to help guide the spacecraft toward its final destination, the unusual metallic asteroid Psyche. The flyby also provides an important chance to test and calibrate the spacecraft’s science instruments before it reaches the asteroid in 2029.
Psyche Spacecraft Captures Mars Images
During the encounter, the mission team plans to use Psyche’s multispectral imager to collect thousands of observations of Mars. The data will help scientists refine imaging techniques and practice operations they will later use while orbiting the asteroid Psyche.
The spacecraft has already begun returning images ahead of the flyby. Starting on May 7, the mission website began displaying the first unprocessed, or “raw,” images showing a starfield with Mars appearing as a tiny point of light. Engineers will later process the flyby images by adjusting brightness and contrast, and they expect to create a time-lapse sequence of the event in the weeks ahead.
To make sure the spacecraft was precisely lined up for the maneuver, the operations team carried out a trajectory correction maneuver on Feb. 23. During that adjustment, Psyche fired its thrusters for 12 hours to fine-tune its course and slightly increase its speed before reaching Mars.
“We are now exactly on target for the flyby, and we’ve programmed the flight computer with everything that the spacecraft will do throughout May,” said Sarah Bairstow, Psyche’s mission planning lead at NASA’s Jet Propulsion Laboratory in Southern California, which manages the mission. “This is our first opportunity in flight to calibrate Psyche’s imager with something bigger than a few pixels, and we’ll also make observations with the mission’s other science instruments.”
What Mars Will Look Like During the Flyby
Psyche’s view of Mars will look very different from the familiar bright images often seen from orbiters and telescopes. Because the spacecraft is approaching from the night side of the planet, Mars will first appear as a thin crescent illuminated by only a narrow strip of sunlight.
“We are approaching Mars at a very high phase angle, which means we are catching up with the planet from its night side with only a sliver of sunlight creating a thin crescent,” said Jim Bell, the Psyche imager instrument lead at Arizona State University in Tempe. “The thin crescent on approach and the nearly ‘full Mars’ view after we fly past create opportunities for the imaging team for both great calibration observations as well as just plain beautiful photos.”
Scientists are also interested in the possibility that Mars may have a faint dusty ring, sometimes called a torus, surrounding the planet. Researchers believe micrometeorites striking Mars’ moons, Phobos and Deimos, may throw dust particles into space. Depending on how sunlight lines up during the flyby, some of that dust could become visible in Psyche’s observations.
The spacecraft’s imager will also perform “satellite search” observations around Mars. These tests are intended to prepare the mission team for searching for possible moonlets orbiting the asteroid Psyche later in the mission.
Other instruments aboard the spacecraft could gather valuable information during the flyby as well. Psyche’s magnetometer may observe Mars’ magnetic field interacting with charged particles from the Sun. Meanwhile, the gamma-ray and neutron spectrometer will study changes in cosmic rays (highly energetic subatomic particles from interstellar space) as the spacecraft passes the planet.
“Ultimately, though, the only reason for this flyby is to get a little help from Mars to speed us up and tilt our trajectory in the direction of the asteroid Psyche,” said Lindy Elkins-Tanton, principal investigator for Psyche at the University of California, Berkeley. “But if all our instruments are powered up, and we can do important testing and calibration of the science instruments, that would be the icing on the cake.”
NASA Tracks Psyche During Mars Gravity Assist
Mission controllers will closely monitor radio signals exchanged between Psyche and NASA’s Deep Space Network (DSN) to confirm the flyby’s success. Changes in the spacecraft’s velocity will appear in the Doppler shift of those radio signals, allowing engineers to quickly determine Psyche’s updated speed and trajectory after it departs Mars and continues toward the asteroid belt.
Several spacecraft already operating at Mars will also assist during the event. NASA’s Mars Reconnaissance Orbiter, Mars Odyssey orbiter, Curiosity rover, and Perseverance rover will contribute observations and navigation support. ESA’s (European Space Agency) Mars Express and ExoMars Trace Gas Orbiter will also take part.
By comparing data gathered by Psyche with measurements from the Mars missions, scientists will be able to improve calibration of the spacecraft’s instruments. Coordinated radio tracking through the DSN may also help future spacecraft navigation efforts during later missions to Mars.
