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
6 p.m. Pacific Time
A communications problem between the Mars Pathfinder rover and lander has been solved, the Mars Pathfinder operations team reported at a 5 p.m. press briefing. Engineers are ready to move ahead with deployment tonight of the rover's ramps and the rover itself.

Although the operations team was not able to pinpoint a specific event that could explain the communications fix, information from a 3:20 p.m. downlink session suggested that it might have been the lander's flight computer which, for unknown reasons, reset itself at the end of the first day's activities.

"The spacecraft is fine," said Richard Cook, Mars Pathfinder mission manager. "It essentially operated all night, just as it was supposed to and we got all the data back showing that all subsystems were fine, but we're a little perplexed as to what happened (with the flight computer). We'll be getting back more diagnostic data later and we should be able to figure it out. "

Telecommunications engineers discovered last night that the Sojourner rover, which is programmed to communicate with the lander as frequently as every minute, was not "completing full sentences" in its transmissions to the lander. The rover team thought the faulty communications might have been the result of a software synchronization problem between the rover's modem and the lander. With new information from today's high-gain downlink session, however, they discovered that the flight computer had reset itself at the end of the first day of activities at about 10:30 p.m. PDT on July 4. The automatic reset may have overwritten previous software timeout commands. As more telemetry becomes available, the team will be able to identify and understand the problem. In the meantime, they were not concerned about a repeat performance since the problem is solvable.

New images also were returned during the mid-afternoon downlink session. Immediately after the press briefing, Mars Pathfinder camera team leader Dr. Peter Smith, of the University of Arizona, and six of his team members rolled out a banner 360- degree mosaic of the Ares Vallis landing site made from all of the image frames received to date.

The rover team sent commands to Pathfinder late today to acquire more imagery of the ramps and Martian terrain around the regions where the ramps would touch the surface. They expected to deploy both ramps by about 7 p.m. PDT, with rover deployment to follow two or three hours later. If the rover rolls onto the surface of Mars by the end of Sol 2 tonight, it would be instructed to place its alpha proton X-ray spectrometer on the ground and take measurements of the soil overnight.

NASA TV will continue to carry coverage of events as they unfold this evening, including ramp and rover deployment. A final wrap-up briefing, scheduled at 9 p.m. PDT, may be canceled if no new developments have occurred by that time. The next scheduled briefing will be held at 10 a.m. PDT on Sunday, July 6, in JPL's von Karman Auditorium.

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