David Gruel, a NASA engineer who spent four years working on the Pathfinder mission that beamed stunning images of Mars back to Earth, will speak at the University of Rochester next week.

Gruel's multimedia presentation, "Mars Pathfinder: Technical Magic on Mars," will be at 7 p.m. Monday, Oct. 20 in Hubbell Auditorium on the University's River Campus. The presentation is free and open to the public, but tickets are required.

Gruel worked with colleagues at NASA's Jet Propulsion Laboratory in Pasadena, Calif. to assemble, test, and launch Pathfinder, which began probing Mars on July 4. As lead engineer of the project's Flight System Testbed, Gruel created a simulated Martian terrain for tests of Pathfinder's ability to bounce safely to the rocky surface in its protective layer of airbags.

Gruel's visit is co-sponsored by the Rochester chapter of the American Society of Mechanical Engineers and the engineering colleges of the University of Rochester and Rochester Institute of Technology. To request tickets, please call the Rochester Engineering Society at 254-2350.