PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Mars Pathfinder Mission Status
July 5, 1997
11:50 p.m. Pacific Daylight Time
Mars Pathfinder's robust, 23-pound rover named Sojourner successfully rolled off its ramp tonight and onto the Martian surface, becoming the first robotic vehicle ever to explore the surface of another planet.

The first image showing Sojourner with its six wheels firmly planted in sandy Martian terrain was received on Earth at about 10:59 p.m. PDT. Images of Rover deployment were returned until Earth set, at which time telecommunications on Mars ceases as the Earth disappears (about midnight PDT) below the horizon. Two-way communications resume at about 11 a.m. PDT on Sunday, July 6.

The operations team examined a set of black-and-white images showing the ramp deployment before activating the command sequence to deploy the rover. More than 90 frames coming down during an 8 - 9:15 p.m. PDT transmission showed that both ramps were situated at angles well within the limits of safe deployment. The rover team sent Sojourner down the rear ramp, or the ramp on the right side of the lander, which was tilted at just 20 degrees from the surface. The rover would not have been able to roll off the ramps had they exceeded a 30-degree tilt.

Sojourner made the trek down its ramp in two stages, first crawling half way down the ramp and stopping to take a photograph of the ramp, then continuing its 4-minute journey off the ramp. Additional images showed rover wheel tracks in soft Martian soil and the rover standing about 10 centimeters (0.3 feet) from the end of the ramp. The lander's camera also took photographs of the rover's exit. Once off the ramp, Sojourner unlatched its primary science instrument, an alpha proton X-ray spectrometer, and positioned it face down in the Martian soil to take 10 hours of measurements overnight.

The first science investigations beginning on Sunday, July 6, the third day of surface operations, are likely to include a soil mechanics experiment to observe how the rover's wheels and mobility system operate on the Martian surface and a rover photography session to create a "monster pan" of the surface in multiple color, high resolution format. The operations team also plans to increase Pathfinder's data rate to 6,300 bits per second to retrieve as much data as possible over the next week, which marks the primary lifetime of the rover.

A press briefing to announce science activities for day three is scheduled for 10 a.m. PDT on Sunday, July 6, in JPL's von Karman Auditorium.

The public is encouraged to follow Mars Pathfinder mission activities via the World Wide Web by visiting the Pathfinder site at: http://mpfwww.jpl.nasa.gov.

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