Jim Lloyd with the Mars Exploration Rover program holds a computer chip with about 35,000 signatures of visitors to the Jet Propulsion Laboratory.

Jim Lloyd, with the Mars Exploration Rover program, holds a computer chip with about 35,000 laser-engraved signatures of visitors to the Jet Propulsion Laboratory. The chip will be placed on the second rover to be launched to Mars (MER-1/MER-B); the first rover already has one. The signatures include those of senators, artists, and John Glenn. The identical Mars rovers are scheduled to launch June 5 and June 25 from Cape Canaveral Air Force Station.