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Mars Pathfinder Mission Status
December 4, 1996
Noon Pacific Standard Time
NASA's Mars Pathfinder is reported to be performing well on the first day of a seven-month journey to the red planet following a perfect launch today from Cape Canaveral, FL at 1:58 a.m. Eastern time.

"The spacecraft team was ecstatic at seeing good spacecraft data," said Brian Muirhead, Pathfinder Deputy Project Manager at NASA's Jet Propulsion Laboratory. "The command and data telecommunications subsystems are working perfectly, sending down data at 1,183 bits per second. The temperature control and propulsion subsystems reported all temperatures and pressures are within expected ranges. All systems are healthy," he said. Pathfinder is traveling away from Earth at a speed of 3.9 kilometers (2.4 miles) per second.

The Delta II launch vehicle performed flawlessly, placing the spacecraft on its trajectory to Mars well within acceptable limits. NASA's Deep Space Network acquired the spacecraft telemetry signal on schedule, about five minutes after separation of the Delta's third stage. When Pathfinder came out of Earth's shadow at one hour and 38 minutes after launch, the solar arrays took over powering the spacecraft as planned. "Power from the array looks to be about 10% better than initially predicted," said Muirhead.

Pathfinder engineers continue to analyze data from the spacecraft's sun sensor, an instrument that helps the spacecraft determine its orientation with respect to the Sun. "The sensor's voltage output is below expected levels but it does appear to be giving good data," said Muirhead. Navigation data and the sun sensor data agree and show the spacecraft to be properly oriented, spinning at the expected 12 rpm and pointed 26 degrees off the Sun. Later today, Muirhead said, the spacecraft will be commanded to switch to a redundant sensor head to see if it is also performing at a low voltage. "Should the problem persist, we have a number of workaround options and there is no risk to the continuation of the mission."

Carried inside the cone-shaped spacecraft is Sojourner, the small robotic rover that will roll out to traverse the surface of Mars when the spacecraft makes its Martian landing on July 4, 1997. It will be the first spacecraft to land on Mars since NASA's Viking mission soft-landed two spacecraft there in 1976. Pathfinder is the second mission in NASA's Discovery program, which is designed to send low-cost spacecraft with highly focused mission objectives to explore space.

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