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.…