Photo received from recovering Spirit rover

Photo received from recovering Spirit rover

BY JUSTIN RAY SPACEFLIGHT NOW January 28, 2004

See:
http://spaceflightnow.com/mars/mera/040128spirit.html
for the photo

Working as space-age surgeons 100 million miles away, ground controllers
are trying to precisely pinpoint the software glitch that halted the Mars
rover Spirit's mission to explore Gusev Crater last Wednesday. If
successful, officials say the robot geologist could be out of recovery
and back at work early next week.

In a promising development late today, Mission Control released the first
photograph taken by Spirit since the rover's computer problems began. It
shows the rover's science arm reaching out to examine a pyramid-shaped
rock nicknamed Adirondack.


Spirit took this image on January 28 and relayed it to Earth, the first
picture from the rover since problems began a week earlier. Credit:
NASA/JPL

As seen by the rover's front-facing hazard-avoidance camera, the arm
remains where it was on the morning of Sol 18 when things began to go
awry. The German Mossbauer Spectrometer instrument is seated over the
rock in a search for iron-bearing minerals.

After finishing the Mossbauer investigations, the arm was supposed to use
the Rock Abrasion Tool to scratch away part of Adirondack's exterior to
create a window inside. But that never occurred.

Spirit's computer system, its flash memory bogged down by too many data
files, began a continuous series of resets. Contact with Earth was lost
for a time.

Now, controllers have managed to get a better handle on their $400
million spacecraft to find the exact source of the problem and delete old
files that aren't needed.

"We are attempting to get a trace from the flight software of the problem
and compare that to what we believe it to be, what we have seen in the
testbed, make sure we are correct and then move forward in deleting some
of the files from our flash file system as a result of understanding the
problem," mission manager Jennifer Trosper said Wednesday.

"We are extremely careful because we want to make sure that we don't make
an error in deleting files. The we have done file deletes on the
spacecraft before, so we've shown that does work. The file directories
have all different names and you can convince yourself that you are
actually deleting the right thing."

Controllers are trying to run a computer script in the rover to track
down the bug. But as of mid-day Wednesday, Trosper said things had not
gone according to plan.

"Over the past two days we have had some difficulty getting the script to
run on the vehicle. So we are continuing to work that problem.

"The method we are using right now in running this script -- it's kind of
a back door into the flight software -- is a fairly surgical technique to
identify the exact problem and deal with that little problem.

"If we are not able to successfully complete our surgical technique, we
have larger hammers, we like to say, that we can use in order to solve
this problem."

By strategically going after the bug, officials hope to preserve useful
data still stored in the flash memory for later playback to Earth.

"The intent of the last few days has been to maintain the state of the
flash memory. We actually think that the flash is not corrupt. We would
like keep the data that's in the flash memory. If we can't do that based
on the technique we're trying to use then the next step we have is to
actually delete the data that is in the flash memory. We've talked to the
science team. Almost all of the data is replaceable."

Science information waiting in the flash memory includes the Alpha
Particle X-Ray Spectrometer and Mossbauer Spectrometer data collected
during studies of the Adirondack and earlier collaborative observations
between Spirit and the European Mars Express orbiter.

The preview-like thumbnail images of the joint rover/orbiter research
have already been received from Spirit, giving scientists some data to
use if the rest can't be recovered.

"Most of the science that was desired to be done can be done from the
thumbnail images. The science team has agreed that is adequate for the
focus of the experiment we had with Mars Express. Clearly, they would
like to get the rest of it down. But in order to get all the data down it
would take many sols and we have make a risk trade here and a time
trade," Trospher said.

"We will attempt the surgical technique about one more day. If that
doesn't work, we will move forward to the less-surgical techniques. And
hopefully if we are on the right track we would hope at the earliest be
back doing science early next week. If we're not on the right track, it
could take longer than that."

A specialized group of engineers were brought together to revive Spirit
last week and coax the rover back into action. The control team will be
returning to its full size in the coming days, if all goes well.

"The anomaly team right now is probably 15 to 20 people because it is a
focused effort on solving this flight software problem. Last night, we
went to adding probably another 10 people to move towards doing our
nominal timeline. And in a few nights, we will go to the full overnight
timeline of staffing with the science and engineering teams in
preparation for getting Spirit back on its feet for the science mission."

--
Regards, Terry King ...In The Woods In Vermont

The one who Dies With The Most Parts LOSES!! What do you need?