Fwd: Mars Pathfinder Mission Status - 12 July 1997, 12:30 am PDT

From: wecooks@ix.netcom.com
Subject: Fwd: Mars Pathfinder Mission Status - 12 July 1997, 12:30 am PDT
Date: Sat, 12 Jul 1997 18:32:53 -0500 (CDT)

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If people aren't aware of this great listserve, it's wonderful!  Everyday, 
you receive this great summary of Pathfinder events! I signed up on the 
pathfinder page listed at the bottom of the message.  That site is an 
amazing one, too.  For the person who asked Marc about including scientific 
data, the Pathfinder Homepage has the link to all the data you could ever 
want!  janet

To: mpf-status-1@mgsw3.jpl.nasa.gov
From: David Dubov <ddubov@mail1.jpl.nasa.gov>
Subject: Mars Pathfinder Mission Status - 12 July 1997, 12:30 am PDT
Sender: owner-mpf-status-1@mgsw3.jpl.nasa.gov

12 July 1997, 12:30 am, PDT

Flight controllers reestablished radio contact with the Mars Pathfinder
lander tonight and repositioned the Sojourner rover after an initial
communications session did not take place because the spacecraft's computer
reset itself.

Beginning at about 3 p.m. Pacific Daylight Time Friday, the flight team
sent commands to the Pathfinder lander instructing the Sojourner rover to
back away from a rock nicknamed Yogi. The rover had been lodged against the
rock since Wednesday evening; it was believed that commands sent Thursday
to move the rover were not received by the lander because of an error in
the timing of a radio uplink session.

The flight team received a signal from the Pathfinder lander's low-gain
antenna at 6:47 p.m. Friday confirming that the lander received Friday's
commands and was beginning to execute them. The team then expected to
receive data over the lander's high-gain antenna beginning at 8:47 p.m.
However, no signal was received at that time.

The team then sent a command to the Pathfinder lander via its low-gain
antenna at about 9:45 p.m. instructing the lander to send a signal back to
Earth. This signal was received. Flight controllers concluded that the
lander's computer must have reset itself sometime between 6:47 and 8:47
p.m. PDT Friday evening. The commands to move the rover would not have been
executed, because they were scheduled to take place later.

Commands were then sent at about 11 p.m. instructing the lander to point
its high-gain antenna at Earth and begin a half-hour downlink session
sending engineering data reporting on the status of the lander and rover.
Commands were also sent to back the rover away from Yogi. Another command
instructed the lander to take and transmit an image of the rover confirming
that the repositioning had been completed.

At 12:15 a.m. PDT, the Deep Space Network station near Canberra, Australia,
acquired a signal from the Pathfinder lander at the beginning of a
half-hour downlink session sent via the lander's high-gain antenna. Data
sent during this session indicated that the rover did in fact receive and
execute commands to back it away from the Yogi rock and reposition itself
on Thursday. It reexecuted these commands when they were resent Friday. In
addition, an image was received at about 12:25 a.m. which showed the rover
backed away from Yogi.

Friday evening marks the second time that the Pathfinder lander's computer
has reset itself since its landing July 4. The flight team is not certain
why the resets are taking place, but engineers noted that both incidents
occurred during periods of heavy communication between the lander and rover.

Telemetry indicated that all spacecraft and rover systems are performing
normally. Today is Sol 8 of the Mars Pathfinder mission.

For further information, please visit our website at 

Status report prepared by:
Office of the Flight Operations Manager
Mars Pathfinder Project
NASA Jet Propulsion Laboratory
California Institute of Technology
Pasadena, CA 91109

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