On October 13, 2023, NASA launched the Psyche probe, which utilizes a solar-electric propulsion system powered by xenon gas. Instead of depending solely on its thrusters, mission planners are strategically harnessing Mars' gravitational force to navigate the spacecraft toward its ultimate destination: the intriguing metallic asteroid Psyche. This flyby also serves as a crucial opportunity to test and calibrate the spacecraft's scientific instruments prior to its arrival at the asteroid in 2029.
Psyche Spacecraft Captures Mars Images
During its close approach, the mission team intends to leverage Psyche's multispectral imager to gather thousands of observations of Mars. This data will enable scientists to enhance imaging techniques and refine the operations they will later employ while orbiting the asteroid Psyche.
The spacecraft has already begun transmitting images ahead of the flyby. Since May 7, the mission's website has showcased its initial unprocessed images, depicting a starfield with Mars as a distant point of light. Engineers plan to process these images by adjusting brightness and contrast, ultimately creating a time-lapse sequence of the flyby in the coming weeks.
To ensure precise alignment for the maneuver, the operations team executed a trajectory correction maneuver on February 23. During this adjustment, Psyche fired its thrusters for 12 hours, fine-tuning its course and slightly accelerating 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," stated Sarah Bairstow, mission planning lead at NASA's Jet Propulsion Laboratory in Southern California. "This marks our first in-flight opportunity to calibrate Psyche's imager using a larger target, along with observations from the mission's other scientific instruments."
What Mars Will Look Like During the Flyby
Psyche's perspective of Mars will differ significantly from the bright images typically captured by orbiters and telescopes. As the spacecraft approaches from the planet's night side, Mars will initially appear as a slender crescent illuminated by a narrow strip of sunlight.
"We are approaching Mars at a very high phase angle, meaning we are catching up with the planet from its night side, revealing only a sliver of sunlight," explained Jim Bell, the imager instrument lead at Arizona State University in Tempe. "The thin crescent on approach and the nearly 'full Mars' view after we pass create opportunities for both calibration observations and stunning photographs."
Scientists are also eager to investigate the potential existence of a faint dusty ring around Mars, possibly formed by micrometeorites striking its moons, Phobos and Deimos. Depending on the sunlight's alignment during the flyby, this dust could be visible in Psyche's observations.
The spacecraft's imager will also conduct "satellite search" observations around Mars, preparing the mission team for future searches for moonlets orbiting the asteroid Psyche.
Other onboard instruments may gather valuable data during the flyby. Psyche's magnetometer could observe interactions between Mars' magnetic field and charged particles from the Sun, while the gamma-ray and neutron spectrometer will analyze changes in cosmic rays as the spacecraft passes the planet.
"Ultimately, this flyby aims to gain a gravitational boost from Mars to accelerate us and adjust our trajectory toward the asteroid Psyche," said Lindy Elkins-Tanton, principal investigator for Psyche at the University of California, Berkeley. "However, if we can power our instruments for important testing and calibration during this flyby, it will be a significant bonus."
NASA Tracks Psyche During Mars Gravity Assist
Mission controllers will carefully 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 be evident in the Doppler shift of these signals, allowing engineers to promptly assess Psyche's updated speed and trajectory as it continues toward the asteroid belt.
Several operational spacecraft at Mars will also support the event. NASA's Mars Reconnaissance Orbiter, Mars Odyssey orbiter, Curiosity rover, and Perseverance rover will contribute observations and navigation assistance, alongside ESA's Mars Express and ExoMars Trace Gas Orbiter.
By correlating data collected by Psyche with measurements from ongoing Mars missions, scientists can enhance the calibration of the spacecraft's instruments, paving the way for improved navigation efforts in future Mars missions.