Update on Mars Mission

From: Jan Wee <jwee@mail.arc.nasa.gov>
Subject: Update on Mars Mission
Date: Thu, 02 Jan 1997 17:21:40 -0600

Dear discuss-lfm members,

Just in case you haven't had time to access the NASA JPL
Mars Pathfinder web site and check on how Mars Pathfinder
is doing, here is the latest update.

Hope everyone had a relaxing break if you were on vacation
over the holidays!  We are all looking forward to the start of
our Planet Explorer Toolkit debate which will begin next week
on Monday, Janaury 6th.  Thanks to all who have posted their
Planet Explorer Toolkit proposals and yes, even to those of you
who posted after the December 20th deadline.  We plan to include
all your ideas (even if you got caught in the holiday rush!)

Welcome back to LFM!

Jan Wee



                                      December 18, 1996

                               12:00 p.m. Pacific Standard Time

Sojourner, a 10-kilogram (22-pound) rover tucked away on a petal of the 
Mars Pathfinder spacecraft, got a 'wake up' call on Dec. 17 from flight 
controllers at NASA's Jet Propulsion Laboratory. After waking up, Sojourner 
conducted an internal health check and sent data back to the flight team 
that all was well.

The Pathfinder flight team was ecstatic with the rover data, which
showed that all systems within the rover were operating normally. In 
addition, data from the rover's main science instrument -- the alpha 
proton x-ray spectrometer -- showed that it was operting properly.

"The rover woke up, did its internal health check, sent the lander 
its status data and went back to sleep, all as planned," said
Art Thompson, rover operations team member. "All subsystems were 
verified as being in good health."

Pathfinder continues to perform very well on its 500 million-kilometer 
(310 million-mile) journey to Mars, the team reported.  Currently the 
spacecraft is 4 million kilometers (2.5 million miles) from Earth, traveling 
at a speed of 3.1 kilometers per second (7,000 miles per hour). Its 
destination, Mars, is currently about 190 million kilometers (118 million
away. All temperatures and power utilization of the lander and cruise 
stage remain at their predicted levels for this phase of the mission.

The spacecraft was spun down from 12.3 rpm to 2 rpm on Dec. 11. Flight 
controllers first instructed the spacecraft to turn to a Sun angle of 
50 degrees and an Earth angle of 32 degrees. This allowed them to use 
all four operating Sun sensors. The spacecraft executed the commanded 
spin down to the normal cruise spin rate of 2 rpm in steps of 2 rpm 
at a time.

Once the normal spin rate was established, the team turned on the 
spacecraft's star scanner on Dec. 12. Star scanner data allows the 
spacecraft to establish full, three-axis knowledge of its orientation 
in space. This is the normal cruise attitude control mode and the 
one in which all trajectory correction maneuvers will be performed.

While Sun sensor #5 continues to work well after a software fix, the 
flight team continues to investigate the cause of the loss of Sun sensor 
head #4. The team expects to reach a likely conclusion on the cause of 
the problem within the next month or two.

Dave Gruel, Pathfinder flight director at JPL, conducted the Dec.16 
health check of the lander science instruments, including the atmospheric 
sensor instrument and meteorology (ASI/MET) package and the imager. 
Temperature, pressure and accelerometer readings from the
instrument verified it was in normal working order. Power and dark current 
measurements received from the imager while it was imaging the darkness 
around it, confirmed that the instrument was working properly, Gruel said.

Richard Cook, Pathfinder mission operations manager at JPL, reported 
today that Pathfinder has been fully checked out for this phase of 
the mission and that all subsystems are "go" for a successful seven-month 
cruise to Mars.

The next major in-flight event will be Pathfinder's first trajectory 
correction maneuver, which is scheduled for Jan. 4, 1997.

Provided courtesy of:

                                 PUBLIC INFORMATION OFFICE

                                 JET PROPULSION LABORATORY

                            CALIFORNIA INSTITUTE OF TECHNOLOGY


                       PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011