UPDATE # 58 - October 21, 1997

PART 1: Rock Stars: Immediate Action Required!
PART 2: New Challenge Question
PART 3: Pathfinder Journal 1: Take a Deep Breath
PART 4: Pathfinder Journal 2: Is This the End?
PART 5: Mars Pathfinder Mission Status
PART 6: Subscribing & Unsubscribing: How to do it!

ROCK STARS: IMMEDIATE ACTION REQUIRED!

Everyone has at least a couple -- interesting, bizarre or
beautiful-looking rocks that have caught your eye while hiking, crossing a
stream, or just digging in your garden. Ever wonder what kind of rock it
is, what it's made of or how it was formed? If so, here's an opportunity
for you find out! Send in a PEBBLE-SIZE rock and it may be one of the
randomly selected pieces to be analyzed by a planetary geologist, on
camera, during the November 13 live broadcast "Today on Mars"!

Wrap up your thumbnail-size rock and a classroom photo of you and your
kids in a padded 4X6 envelope and send it to: 
Passport to Knowledge
PO Box 1502
Summit, New Jersey 07902-1502

Be sure to include your name, your school's name, grade level, type of
class and number of kids in class. Sorry, but the rocks and photos will
not be returned. Photos can also be submitted electronically to:
sandy@quest.arc.nasa.gov. For general directions on how to submit images
and in what format go to: http://passporttoknowledge.com/lfm/events

***DEADLINE FOR SUBMISSION: OCTOBER 30***

NEW CHALLENGE QUESTION

Last week's question--
CQ#2: NASA's Mars experts are tracking temperature, wind speed and
direction. To do that accurately, they place the meteorology mast at the
end of one of the solar panels. Why do they do that, rather than closer to
the main body of the spacecraft?

Hint: Why do terrestrial weathercasters put their instruments in the
middle of open fields?

Answer: Researchers want to maximize their chances of recording
measurements unaffected by the warmth of the lander's other instruments
and fluctuations in wind speed caused by the flow of the wind over the
bulk of the lander.

New question for the week--
CQ#3: There may or may not be a face on Mars, but there's certainly a
grin! What is it and where is it? 

Hint #1: On Mars you might need Sojourner's camera to see it because
there's no mirror for this face to look in.
Hint #2: This is far and away our most impish Challenge Question ever!

For the answer, check here next week. Have fun!

PATHFINDER JOURNAL 1: TAKE A DEEP BREATH

[Editor's Note: Bridget Landry is the deputy uplink systems engineer on
Mars Pathfinder. She is responsible for making sure the computers on the
ground talk the same language as the computers on the spacecraft.]

October 3, 1997

While I didn't actually WANT us to lose contact with the spacecraft, we've
kind of been expecting it; the battery has been on its last legs for
awhile. However, I heard an almost audible sigh of relief from most of the
team at having a chance to get caught up. To get papers written. To
actually LOOK at some of the huge quantity of data that have come down
during this mission. To take a day off to get a haircut, or our teeth
cleaned, or the oil changed in the car.

Personally, I was finally able to put up the Web page for the Europa
project that I had promised would be up in May! Not all of the delay was
my fault (couldn't put a page on a computer if I didn't have access), but
I was feeling guilty over not having gotten it done before. Now it's up,
with most of the info on it and I was even able to make it self-contained
so that it can be moved, lock, stock and gif files to another server. (The
one it's currently on can't handle all the traffic we're expecting.)

This has been an incredible project and taking a few minutes to step back
and put it in perspective has helped. We get so caught up in the nuts and
bolts of putting commands together, testing commands, thinking of new
experiments we want to try, that we loose the big picture, the wonder of
what we've accomplished this summer and over the last three years. What an
amazing experience!

PATHFINDER JOURNAL 2: IS THIS THE END?

[Editor's Note: Bridget Landry is the deputy uplink systems engineer on
Mars Pathfinder.]

October 15, 1997

Still no word from the spacecraft. This is getting scary.

The last data we had from the spacecraft came down on September 26. We
expected it to wake up the next day about 2 a.m. (Mars local time) to take
pictures of the morning sky, but we never heard from it that day. We
assumed that the battery had finally died and that the spacecraft had
dropped into a contingency mode. However, we heard nothing from the
spacecraft in the next few days, so we attempted to command it to turn on
the auxiliary transmitter (in case the main one was broken in some way).
This appeared to work as we heard a signal from the spacecraft on October
7, starting and stopping exactly when we expected it to. However, the same
commands, sent at the same times, failed to produce any result on the
succeeding three days and we have had no contact since then.

Theories abound, of course. One is that because the transmitter and the
spacecraft have been off for so long, the spacecraft is cooling down to
temperatures below where it was tested. This may have changed the
wavelengths at which the spacecraft is transmitting and receiving, but
much more than anticipated. Another is that the switch between the
low-gain and high-gain antennas may be stuck in the high-gain. Also, if
the battery has indeed died, the spacecraft may not be able to track time
correctly, (I have this image of the spacecraft clock flashing "12:00"
like my VCR does when there's been a power outage...) and so isn't able to
point the high-gain antenna properly.

But the fact remains that we haven't had any data from the spacecraft
since September, we can't reliably command the spacecraft and we don't
know what's wrong. And so, as I said before, it's getting scary. This may
be the end of the project. Sad and scary both.

MARS PATHFINDER MISSION STATUS

October 17, 1997, 4:00 p.m. PDT

Today we attempted to make contact with Pathfinder using the 70-meter
station in Goldstone, California. We commanded the spacecraft to turn on
the auxiliary transmitter, but unfortunately we did not see any down link
signal.

Due to commitments to the Galileo mission we moved our operations to the
34-meter antenna and commanded the spacecraft to turn on the SSPA
transmitter. The SSPA is a backup transmitter in addition to our primary
and auxiliary transmitters. Unfortunately, we did not receive any signal
during this second attempt.

We will continue with our efforts to reestablish contact with Pathfinder
and will promptly post any favorable developments.

For further information on the Mars Pathfinder Mission, please call our
Mission Status Report line at 1-800-391-6654.

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