MARS PATHFINDER MISSION STATUS
December 6, 1996
12:00 p.m. Pacific Standard Time
The Mars Pathfinder spacecraft continues to perform well in the early
part of its cruise to Mars, which is about 209 million kilometers (130 million
miles) away today.
Currently the spacecraft is 750,000 kilometers (0.5 million miles) from
Earth, or about two times the distance that the Moon is from Earth, traveling
at a speed of 3.3 kilometers per second (7,400 miles per hour).
The spacecraft is performing just as expected, with the exception of
the sun sensor. The temperatures of the lander and its electronics are at
their predicted levels for this phase of the mission. The cruise stage solar
array, propulsion module and electronics are also at their predicted temperatures.
Two of the four segments of the solar array are currently in use, producing
approximately 250 watts of power, about 10 percent more power than the original
predicts. The battery is charged at 75 percent of its full capacity, and
is showing a temperature of 9 Celsius (48 degrees Fahrenheit), which is
approaching the desired steady state of 8 Celsius (46 degrees Fahrenheit).
The telecommunications system is performing well within its predicted range,
indicating that it will be able to maintain higher data rates throughout
The JPL flight team is continuing its investigation of a lower than expected
voltage reading on the sun sensor. However, since the sensor data are good,
flight controllers have decided to implement a software update to compensate
for this low voltage condition. The software modification has already been
coded and validated in the project's testbed and will be sent to the spacecraft
this weekend. The software modification will allow Pathfinder's on-board
attitude control system to use the sun sensor data in its normal calculations
of the spacecraft's orientation. Once the attitude control calculations
are verified, the planned spin-down maneuver to 2 rpm will be performed,
probably early next week.
The spacecraft is pointed approximately 55 degrees from Earth and 25
degrees off the Sun. Doppler and ranging data continue to look very good.
Because the spacecraft is not pointed directly at Earth, flight controllers
are able to observe the motion of the antenna as Pathfinder spins about
its axis and have confirmed a spin rate of 12.3 rpm.
The latest orbital data from tracking operations at all three Deep Space
Network stations around the world indicate that the magnitude of the first
trajectory correction maneuver, if performed as scheduled on Jan 4, 1997,
would be 29.5 meters per second (96 feet per second).
Mars Pathfinder, the second in NASA's Discovery program of low-cost,
highly focused spaceflight missions, is scheduled to land on the surface
of Mars on July 4, 1997, and deploy a small rover, called Sojourner, to
explore the Martian landscape.
Provided courtesy of:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
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